Studies on Physiological Response to Sportswear Made from Cellulosic Fibres

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1 Studies on Physiological Response to Sportswear Made from Cellulosic Fibres Malgorzata Zimniewska 1,*, Maria Laurentowska 2, Edyta Bogacz 1, Oliwia Zimniewska 2 1 Institute of Natural Fibres and Medicinal Plants, Wojska Polskiego 71b; Poznan. Poland 2 The University School of Physical Education, Krolowej Jadwigi 27/39; Poznan, Poland *Corresponding author: gosiaz@inf.poznan.pl Abstract: At the times of over saturating the global markets with textiles, consumers have growing expectations towards these goods. The producers, who develop new technologies for giving the textiles additional functions can gain a considerable advantage on the clothes market. This trend forces scientists to investigate new methods of clothing evaluation, because common physicalmechanical tests do not guarantee creation of multi-faceted opinion about properties of the textile. One of the new methods applied for clothes investigation was developed in INF. This method involves the use of medical EMG records for determination of clothing influence on muscles activity. The study on clothing effect on activity of motor units of people wearing garment made from natural and synthetic fibers was conducted in steady conditions without physical effort. The results of the study have shown, that everyday clothing can be a reason of increasing of tendency to tiredness. The aim of the current studies was the investigation of the influence of different types of sportswear on physiological parameters and energetic cost of volunteers in sport conditions. Tested garments were prepared with the application of cellulosic and synthetic fibers. This paper presents the results of the experiment conducted within the studies. The volunteers taking part in the experiment were asked to wear test clothes made from 100% TENCEL fibers, 100% polyester fibers, or a TENCEL / polyester blend and do 10-minute physical exercise with using a racing track. The physiological parameters as well as parameters of respiratory and circulatory system for estimation of energetic cost of physical effort were monitored in case of each subject wearing different types of sportswear. The results of the study show statistically significant differences in the measured parameters between different types of tested sportswear. Especially, the energetic cost of volunteers physical effort was lowest with the garments from TENCEL / polyester blend. This effect can be connected to better moisture management, which supported the body temperature regulation leading to lower energetic cost for the given performance. Keywords: sportswear, polyester, Tencel, energetic cost, physical effort 1. Introduction The aim of the studies was investigation of influence of different types of sportswear made from cellulosic manmade fibers and polyester fibers on energetic cost of volunteers effort in sport conditions. The study covered 3 types of clothing made from knitted fabrics: 1. made from 100 % TENCEL, 2. made from blend of Polyester/TENCEL 3. made from 100 % PES The studies were conducted according to the methodology developed by the Laboratory of Physiological Influence of Textile on Human Body in collaboration with Poznan University of Physical Education. 2. The material of the study The objects of the studies were sportswear prepared from different raw materials. The set of investigated clothes was made from knitted fabric single jersey, characterized by sport design and comprised of a shirt with long sleeves and trousers with long legs. Two main groups of raw materials were used for sportswear preparation: TENCEL, a man-made cellulosic fibre of the generic fibre type Lyocell (CLY) [1] from Lenzing AG, Austria, and Polyester (PES). A blend of the fibers was tested as well. Characterization of the fiber is shown in Table 1. All types of knitted fabrics were tested for determination of their biophysical properties. Materials were provided by Lenzing AG, Lenzing, Austria. doi: /tbis

2 Garment design was from Chillaz International, Vomp/Schwaz, Austria. Visualization of metrological characterization of three types of knitted fabrics made from 100% TENCEL fibers, 100% polyester fibers and TENCEL / PES blend are presented in Fig. 1-7; their density is shown in Table 2. Staple length Linear density Shape of cross section Type Table 1 Fibers parameters CLY PES fibre fibre PES filament 38 mm 40 mm filament 1,3 dtex 1,3 dtex 0,63 dtex ** Oval Round Round TENCEL Trevira 350 Fig. 1. Surface mass of knitted fabrics; PN-85/ P-04787; PN 80/ P Table 2. Density of knitted fabrics. Type of raw material Density [nr of looms /10cm] 100% PES PES / CLY cou rses wale cour ses wale cou rses 100% CLY wal e Fig. 2. Air permeability of knitted fabrics PN EN ISO 9237 (Test pressure 200 Pa). As Fig. 1 shows, surface mass of knitted fabric made from polyester had the lowest value, what was result of its lower density of loops. Knitted fabric made from TENCEL was opposite to the polyester fabricsurface mass was at the highest level due to its high density of loops. The structural parameter of tested textiles influenced the level of air permeability. Air permeability of textile material is strongly connected with their structure-low density and low surface mass result in higher value of air permeability. From this it was found, that air permeability of knitted fabric made from polyester was at the highest level, what is shown in Fig. 2. The knitted fabric properties connected with hygroscopicity (Fig. 3) and ability of water sorption (Fig. 4) was considerably worse for polyester fabric; textile from cellulosic manmade fibers in pure form or in blend with polyester shown respectively higher level of hygroscopicity and ability of sorption. The highest time needed to soak in a water drop on the fabric surface, was found for 100% PES fabrics. Fig. 3. Hygroscopicity of knitted fabrics tested in different condition: 65% and 100% relative humidity of air; PN 80/P Textile made of the cellulosic fabrics does not collect electrostatic charges on their surface, as is shown in Fig. 5. The highest level of surface resistance was found for 100% polyester knitted fabric. Even 30 % TENCEL share in blends with polyester in fabrics reduces their ability to collect the electrostatic charges. 623

3 Fig. 4. Time of water absorption Drop method JS No.59/L Fig. 6. Thermal resistance of knitted fabrics PN-EN 31092:1998/Ap1 (ISO 11092:1993). Fig. 5. Electrostatic surface resistance of knitted fabrics (humidity of air 50%). Two biophysical parameters measured with using Sweating Guarded Hot Plate test method showed strong correlation with the type of knitted fabric. Dense structure - the highest number of looms per 1 dm - of polyester knitted fabric resulted in highest level of its thermal resistance. In case of water vapor resistance, presence of polyester fibers in blend with manmade cellulosic fibers in tested knitted fabrics facilitated water vapor transport through the textiles. It means, that regarding the moisture transport, the best properties were found in knitted fabric made from TENCEL /polyester blended fibers, because they had the lowest level of water vapour resistance. 3. Methodology Young men-volunteers constituted the tested group in the studies. Ten volunteers (only men, inspected clinically) were selected from the population of healthy people aged years with similar body constitution, with height from 175 to 190cm and weight from 71 to 100kg. Experiments were conducted in an air Fig. 7. Water vapor resistance of knitted fabrics PN-EN 31092:1998/Ap1 (ISO 11092:1993). conditioned chamber (21 +/- 2ºC) at constant humidity 40 ±5%, between 11 am and 3 pm, from 10th September to 25th September According to previous studies [2,3] in this time of the day the activity of muscle motor units is optimal with the circadian rhythm. Every volunteer wore one type of tested clothes during one day of experiment and other types of clothes in the following days. Each type of set was worn in three different days. Each volunteer was tested during wearing each type of sportswear as well as without any garment. Finally, 30 full measurements were done for each type of sportswear in accordance with the experiment scheme shown in Fig. 8. After half an hour of acclimatization, each volunteer did physical exercise with using a racing track Woodway (treadmill) duration of the exercise 10 minutes: 1st min run with speed 8 km/h 2nd min run with speed 10 km/h remaining 8 min run with speed 12 km/h The tests were conducted as follows: 624

4 First day - with physical exercise conducted with subjects undressed (according to the scheme), Second day with physical exercise conducted with wearing clothes made from polyester/tencel blend, Third day with physical exercise conducted with wearing clothes made from 100% polyester, Fourth day - with physical exercise conducted with wearing tested clothes made from 100 % TENCEL. Fig. 8. Scheme of experiment. The full measurement, which was conducted during the experiment: after 0.5 hour of acclimatization, after physical effort and after 15 minutes of rest, included: tests of temperature and moisture of skin under the sportswear, monitoring of parameters of respiratory and circulatory system for estimation of energetic cost of physical effort for each subject wearing different type of sportswear. Fig. 9 presents photos from ongoing experiment. Fig. 9. Monitoring of parameters of respiratory and circulatory system with application of Oxycon Mobile during the effort on the race track. 4. Results Acclimatization Physical Time of exercise restitution 1) 1) 1) Start of experiment 0,5 h 10 min 4.1. Skin clothes microclimate Up to pulse stabilization 1) Measurement: End of Skin temperature experiment Skin humidity VO 2 oxygen consumption measurements The main parameters of skin - clothes microclimate measured under the tested sportswear are shown in Figures Results of the measurements of physiological parameters of volunteers skin confirm, that physical effort has big influence on skin temperature and humidity. Temperature measurements were conducted from the back skin and skin of the thigh over the examined muscles at each stage of the experiment using a contact thermometer (Teca). Changes in back skin temperature were strongly related to the type of sportswear and the fact of whether the body of the volunteer was covered by a garment or not. A similar tendency was observed in direction of the temperature changes in case of the tests on undressed volunteers and those dressed in garments made from PES/TENCEL blend the back skin temperature fell and hit a minimum at the end of the run, and then rose during restitution. Back skin temperature of volunteers wearing PES/TENCEL clothes, reached the same level after restitution as at the beginning of experiment. The temperature decrease after running phase resulted from triggering of human thermoregulatory system and peaking skin moisture. In the next stage of the experiment, temperature of back skin increased - uncovered skin was drying out and in case of wearing sportswear made from PES/TENCEL blend, moisture was transferred outside. Temperature dipping of uncovered back skin was large, because evaporation surface of sweated back was big, what resulted in quick cooling of the skin. As regards sportswear made from TENCEL, back skin temperature soared and peaked at run conditions opposite to blend of PES/TENCEL and uncovered tests. It could be explained, that during run, sweating did not cause such quick temperature dipping, because sweat, produced by thermoregulatory human system, was absorbed by man-made cellulosic fibers and did not cool the skin. Heat of absorption could help to hold a little bit higher back skin temperature. After restitution the temperature of back skin of volunteers wearing TENCEL garment, came back to the initial level. In case of the garment made from polyester, a slight fall of back skin temperature of volunteers was visiblefrom acclimatization through run to restitution. Big differences in initial temperature level (after acclimatization) of back skin visible on Figure 10 resulted from differences in ambient conditions air temperature was within range from 21 to 23 0 C. Statistical analyses of back skin temperature of volunteers wearing tested garment showed significant differences only between temperature of volunteers in 625

5 TENCEL clothes and clothes made from PES/TENCEL blend, measured after run. 32,60 [ o C] 32,40 32,20 32,00 31,80 31,60 31,40 31,20 31,00 AFTER ACCLIMATIZATION Temperature of back AFTER RUN AFTER RESTITUTION CLY CLY/PES PES TEMP. OF REFERENCE Fig. 10. Temperature of back skin of volunteers wearing tested sportswear-measured after acclimatization, after run and after time of restitution. Temperature of reference means test of uncovered volunteers. The thigh skin had a smaller surface of evaporation and covered working muscles of the legs. For this reason its temperature changed in a different way when compared to back skin. Thigh temperature rose after run, because working muscles produced heat. Even time of restitution did not stop soaring of the skin thigh temperature. Only temperature of uncovered thigh slightly decreased after restitution, due to the cessation of muscle activity and easy, unhindered evaporation of sweat. Statistical analysis of thigh skin temperature of volunteers wearing tested garment shown significant differences in changes between temperature measured after acclimatization and after restitution of volunteers wearing garment made from polyester and without any garment, as well as between volunteers wearing garment made from PES/TENCEL blend and without any garment. Moisture measurements were conducted from the back skin and skin of thigh over the examined muscles at each stage of the experiment using a Corneometer CM 825. Rapid increase of skin moisture on the back and thigh after running was visible in all conditions of the experiment regardless of the garment worn. After reaching the peak, which was the same for all trials, skin moisture decreased during the restitution and in case of thigh reached the initial level for each type of tested garment as well as without garment. In the case of back skin, a faster return to initial level of moisture was observed after the reaching peak recorded when wearing the garment made from TENCEL. Moisture of back skin after restitution, covered by polyester sportswear did not recover to the same level as before physical effort. Polyester shows a low ability of moisture absorption and high level of water vapour resistance so did not permit the moisture to be transported from the back skin to the air. [ o C] 32,00 31,50 31,00 30,50 30,00 29,50 29,00 28,50 28,00 27,50 AFTER ACCLIMATIZATION Temperature of thigh AFTER RUN AFTER RESTITUTION CLY CLY/PES PES TEMP. OF REFERENCE Fig. 11. Temperature of thigh skin of volunteers wearing tested sportswear-measured after acclimatization, after run and after time of restitution. Temperature of reference means test of uncovered volunteers. 140 [%] AFTER ACCLIMATIZATION Humidity of back AFTER RUN AFTER RESTITUTION CLY CLY/PES PES HUMIDITY OF REFERENCE Fig. 12. Moisture of back skin of volunteers wearing tested sportswear - measured after acclimatization, after run and after time of restitution. 140 [%] AFTER ACCLIMATIZATION Humidity of thigh 117,51 113,12 119,85 118,15 27,63 29,63 24,97 32,94 26,67 34,64 31,38 41,88 AFTER RUN AFTER RESTITUTION CLY CLY/PES PES HUMIDITY OF REFERENCE Fig. 13. Moisture of thigh skin of volunteers wearing tested sportswear - measured after acclimatization, after run and after time of restitution. 626

6 120 [%] Humidity of thigh after run CLY CLY/PES PES HUMIDITY OF REFERENCE Fig. 14. Moisture of thigh skin of volunteers wearing tested sportswear - measured after run. 45 [%] Humidity of thigh after restitution CLY CLY/PES PES HUMIDITY OF REFERENCE Fig. 15. Moisture of thigh skin of volunteers wearing tested sportswear - measured after time of restitution Energy Cost Monitoring parameters of respiratory and circulatory system started before physical effort and continued, during the volunteer run and for a further 5 minutes of restitution. The following parameters were recorded: oxygen consumption, minute ventilation, production of CO 2, respiratory exchange ratio (RER) and heart rate. The parameters allowed for determination of energetic cost by indirect method in open system [6,7]. The tests were done with Oxycon Mobile application. Results of the study showed (table 3), that the lowest energetic cost of physical work and time of restitution of volunteers wearing the sportswear was obtained for garment made from PES / CLY blend and the highest energetic cost was recorded for garment made from 100% PES. From the sport-physiological point of view, the lower level of energy usage, the more favourable for the human organism it is, because it allows the body to conduct more intensive physical exercise without disturbing homeostasis. Statistical analysis of the results of the study shows: Statistically significant differences between I type of garment (PES /CLY) in comparison with II (100 % CLY) and III type (100%PES) of sportswear. During this part of the study it was found, that garment made from PES /CLY had the most favourable effect on energetic cost and time of restitution of volunteers and their endurance and efficiency. Table 3. Energetic cost of done physical work and time of restitution for volunteers worn the sportswear Test of energetic cost (Average) Physical effort kcal/10min Restitution (kcal/5min) Physical effort + Restitution kcal/15min Without garment TYP I PES /CLY TYP II 100 % CLY TYP III 100%PES 129,87 126,06 128,40 130,64 14,85 14,28 15,37 16,14 145,02 140,34 143,87 146,81 Comparison of energetic cost of physical work of the volunteers when wearing the sportswear and without garment proved that clothes made from 100% TENCEL, as well as TENCEL /PES blended fibres can result in an improvement in endurance. It can be strongly related to low water vapour resistance of both of the knitted fabrics, which improved transfer of perspiration from the skin surface and supported the body temperature regulation leading to lower energetic cost for the given performance. 5. Conclusions 1. Sportswear, made from TENCEL and polyester fibers and their blend was characterized by different bio-physical properties, which had strong effect on microclimate in skin-clothes area. 2. Parameters of microclimate in the skin-garment area changed in a similar way regardless of the type of sportswear which covered the volunteers body. Physical effort was a very strong stimulus and influenced skin temperature and skin moisture of volunteers in a significant way. Garment type had slight effect on moisture of the skin. 3. Investigation of energetic cost of volunteers physical effort while wearing tested garment showed that garments made from blend of Polyester and TENCEL had the most favourable effect on the energetic cost of physical work, the time of restitution of volunteers and their 627

7 endurance and efficiency. The 100 % TENCEL garment was second best. 4. Statistically significant differences were found between energetic cost of volunteers wearing garment made from blended fibres PES / CLY in comparison to energetic cost of volunteers covered with sportswear made from 100 % CLY as well as made from 100% polyester fibres. Acknowledgement This work was in part funded by the Christian Doppler Research Society, Vienna, Austria. The authors wish to thank Ulf Kattnig, Chillaz International, Vomp/Schwaz, Austria, for providing the garment design. References: [1] White, P. Lyocell: the production process and market development. In: Woodings, C, ed. Regenerated cellulose fibres. Cambridge: Woodhead Publishing; 2001: p [2] Huber J, Torlińska T, Skoracka J, Witkowska A, Szukała A, Bryl A. Daily fluctuation of healthy human muscle motor units activity in electromyographic examinations. Medical News, Nowiny Lekarskie, 2007, 76, 5, [3] Zimniewska M, Huber J, Krucińska I, Torlińska T, Kozłowski R. The influence of the natural and synthetic fibers on the activity of the motor units in chosen muscles of the forearm. Fibers and Textiles in Eastern Europe, 2002, 10, 4, [4] Schuster KC, Suchomel H, Männer J, Abu-Rous M, Firgo H. Functional and comfort properties of textiles from TENCEL fibres resulting from the fibres water-absorbing nanostructure. a review. Macromolecular Symposia, 244,1, 2006, [5] H. Pessenhofer, F.Suchomel, B. Kohla, N. Sauseng, Optimization of physical performance with TENCEL blends. 46th Dornbirn Man-made Fibers Conference, September, 2007 [6] V. Díaz, P. J. Benito, A. B. Peinado, M. Álvarez, C. Martín, V. Di Salvo, F. Pigozzi, N. Maffulli, F. J. Calderón, Validation of a New Portable Metabolic System During an Incremental Running Test, Journal of Sports Science and Medicine 7, 2008, , [7] Bringard A, Perrey S, Belluye N. Aerobic energy cost and sensation responses during submaximal running exercise: Positive effects of wearing compression tights, International Journal of Sports Medicine, 2006,5:

8 Evaluation of Different PPE Ensembles in terms of Sensation, Usability, Satisfaction and Preference Yue-Ping Guo 1, Yi Li 1,*, Thomson GC Wong 2, Joanne HY Chung 2, Anthony SW Wong 2, Mayur DI Gohel 3, Polly HM Leung 3, Ameersing Luximon 1 1 Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong, China 2 Schools of Nursing, the Hong Kong Polytechnic University, Hong Kong, China 3 Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China * Corresponding author s tcliyi@polyu.edu.hk Abstract: The purpose of this study is to assess the subjective responses on discomfortable sensation, usability, overall satisfactory level and preference while wearing five types of personal protective equipment (PPE) ensembles. Ten subjects exercised on a treadmill, worked on a computer, and moved a mannequin in a simulated environment, replicating a health care worker s routine. Results show that the subjective discomfort perceptions, usability, overall satisfactory level and preference are different for the different ensembles. The perceived thermal, wet and overall discomfortable sensation in the entire body were significantly correlated with those under the mask. Overall discomfortable sensations both under the mask and in the entire body significantly influenced the overall satisfactory level of ensembles. This paper discusses how the air-tightness, weight and construction may be responsible for the usability difference between PPE. The fitness of the mask is a significant factor affecting the overall discomfortable sensation under the mask and overall satisfactory level for PPE ensemble. Keywords: Personal protective equipment, uncomfortable sensations, usability, satisfactory level, preference 1. Introduction In hospital and field settings, the use of personal protective equipment (PPE), ranging from surgical scrub suit, surgical cap, impervious gown or apron with full sleeve coverage, goggles or face shield, shoe covers, gloves and N-95 or N100 respirators, is mainly recommended to control infection and limit outbreaks of serious infectious diseases such as SARS and avian influenza (H5N1) [1,2]. PPE is the most effective strategy [3-7], therefore an array of PPE are widely available in the market. However, the selection of the PPE is generally based on the filtration efficiency of mask or barrier effectiveness of personal protective clothing (PPC), without due consideration of wearer acceptance. In evaluating the effectiveness of PPE, wearer acceptance should be considered and the factors related to wearing masks, includes comfort, interferences with vision, communication and job performance, resistance to breathing, fatigue and confidence in the device s effectiveness, are recommended [8]. However, studies have investigated only several aspects of subjective strain such as respirator constraint [9], thermal sensation, skin moisture [10], visual impairment and the acceptable duration of wear [11]. Other studies have examined the subjective responses of wearing PPE ensemble in chemical [12] and asbestos industries [13,14] and in two short physically simulated demanding tasks [15]. These studies concluded that PPE may significantly influence clothing comfort, heat perception, breathing difficulty, skin moisture and overall favor even during work in a nature environment or in a real working situation. Two main reasons were the collocation and weight of the equipment. A recent study has examined the usability of different protective clothing commonly worn by health-care workers taking care of patients at Hong Kong hospitals [15]. The study found that putting on - taking off different clothing took different times, implying the usability differences between PPC. Furthermore, the study discussed that the weight, fabric thickness and construction of clothing might be responsible for the usability differences between PPC. However, the studies discussed only cover PPE ensemble used in the chemical and asbestos industries or protective clothing without masks used in areas of infection control alone. Few studies have covered PPE doi: /tbis

9 ensemble with clothing and facial protective equipment used in areas of infection control. Other factors affecting the uncomfortable sensations and overall satisfactory level of PPE ensemble such as the airtightness of PPE and the fitness of the mask have not been investigated. Also, it is necessary to observe the relationship between specific subjective responses. The purposes of this study were to evaluate the subjective responses on the uncomfortable sensations, usability, overall satisfactory level and overall preference while wearing five types of PPE, and to explore relationship between whole body and under the mask on thermal, wet and overall uncomfortable sensations, as well as the subjective factors affecting discomfort sensation, satisfactory level, and preference. 2. Methodology 2.1 Participants same material as gown of PPE 2) (F2), a half-sleeved surgical scrub suit (described by the designer as made of a material with antibacterial and antiviral functions) (S3), and a polypropylene mask with two exhaust holes (Mask B). This was custom made for this study. PPE 4: A commercially available nowoven surgical gown (Winner Medical Group, F3), a S1 and a surgical mask (Winner Medical Group); PPE 5: A conventional pure cotton surgical gown (from a public hospital in Hong Kong) (F4), an S1, a surgical mask (Winner Medical Group) and disposable goggles. In addition to the above, on each occasion each volunteer wore a pair of disposable gloves, a cap (except for PPE 2) and a pair of spun-bonded polypropylene shoe covers. Total weights (g) (mean ± SD) of the ensembles were ± 21.8, ± 23.9, ± 16.8, ± 18.4 and ± 33.3 for PPE 1 to PPE 5 respectively. The experimental protocol was approved by the Human Subjects Ethics Sub-Committee of the Hong Kong Polytechnic University prior to beginning the experiment. The participants gave informed consent to take part in this study. The participants were yr old healthy males (five) and females (five), and all were nursing students. They were recruited from the School of Nursing at The Hong Kong Polytechnic University. The physical characteristics (mean ± SD) were 22.4 ± 0.55 years of age, ± 3.42 cm height, ± 4.72 kg body mass, 1.68 ± 0.08 m 2 body surface area in the male subjects, and 22 ± 1.41 years of age, ± 6.22 cm height, ± 3.18 kg body mass, 1.41 ± 0.06 m 2 body surface area in the female subjects. PPE 1: Barrierman (DuPont Tyvek) and N95 face mask PPE 2: Custom designed breathable protective gown PPE 3: Custom designed protective apron with antibacterial and antiviral functions 2.2 PPE Tested Fig. 1 illustrates the five ensembles used in this experiment, designated PPE 1-5. Each is described below: PPE1: 100% polyethylene barrierman (DuPont Tyvek) (F1), a commercially available pure cotton surgical scrub suit worn inside barrierman (S1), an N95 respirator (3M 1860) (3M Canada Company) and a disposable face shield; PPE2: a waterproof breathable protective gown with a head cover (F2), a surgical scrub suit worn inside gown (S2), and a respirator with exhaust valves and ventilation pipes (respirator A). This was custom made for this study; PPE 3: A protective apron without sleeves (the PPE 4: Nonwoven surgical gown and surgical mask (Winner Medical group) PPE 5: Conventional surgical gown (HK public hospital), mask and goggles Fig. 1. Five different types of personal protective equipment ensembles used in this experiment. These five types of protective clothing were selected for the test because these include conventional types being used in health care settings in Hong Kong 630

10 (PPE 1, 4 and 5) and newly devised types (PPE 2 and 3). The physical properties of the fabrics are listed in Table 1. Table 1 Mean physical characteristics of the fabrics Fabric Weight (gm/m 2 ) Thickness (mm) Fabric count (yarns per inch) warp Filling S1 Mean SD S2 Mean SD S3 Mean SD F1* Mean N/A N/A SD N/A N/A F2 Mean SD F3* Mean N/A N/A SD N/A N/A F4 Mean SD *Nonwoven fabrics. Others are woven. N/A: Not available 2.3 Experimental Protocol The present study was designed to simulate an environment where the medical health workers work (room temperature (T a ) = 25 ± 1 C, Relative Humidity (RH) = 60 ± 3 %). In a cycle of experiment, the subjects were required to carry out a simulated task similar to the ones done by health care workers in the hospital ward. These included working on a computer (printing a paper and simulating that healthcare workers are dealing with medical documents), moving a mannequin (simulating to move a patient), exercising on a treadmill (simulating to care for patients in the hospital ward), having lunch and so on. In order to simulating for patients care in the hospital ward 4 km/hr intensity of exercise for 25 min twice a day were chosen, because the subjects considered the workloads were similar to those they experienced in the hospital ward when caring for patients during preliminary tests. Each of the subjects completed 7 hours of standardized activities on five separate days. On a typical experimental day, subjects were requested to arrive at the experimental laboratory after having voided their bladder before 10 am. The experiment started from 10 a.m. onwards. After 20 minutes in the sitting position, the subjects exercised on the treadmill for 25 minutes at a walking speed of 4 km/hr. They then worked at set tasks on a computer station for the next 60 min. Next, the subjects moved a mannequin and walked at their own pace 20 times across the room (about 10 m per traverse). At 1 pm, lunch was provided. After lunch, the volunteers rested until 02:00 pm, and then repeated the exercise and computer tasks. The subjects then took off the protective ensemble at 05:00 pm, after resting. Therefore, each type of protective clothing was worn for 7 hours during the course of the study. It should be noted that, in the PPE 1 and PPE 2 ensembles, the head cover and face shield were worn for only one hour in the morning and one hour in the afternoon, when performing exercises and working on the computer. There was an interval of three days between two consecutive experimental days. 2.4 Subjective Measurements The subjects rated the subjective responses under the mask and in the whole body (under the clothing) conditions separately before and after morning exercise on the treadmill; after moving a mannequin in the morning; after lunch; after afternoon exercise and working at the computer; and before the end of the trials (the masks were removed at that moment), in terms of the subjective perceptions feeling humid, hot, airtight, prickly, unfit, odorous, fatigued, heavy and overall discomfort separately for under the mask and under the clothing. Subjects were also required to rate the overall satisfactory level for PPE ensembles as a whole immediately following the above testing session. Before the end of the trials, the subjective ratings with regard to the evaluation of usability for the mask and clothing were completed by the subjects: difficulties in putting mask on, difficulties in taking mask off, mask interferences in vision and in communication, difficulties in putting clothing on, difficulties in taking clothing off, clothing interference in job performance. Each subject also rated the overall preference regarding mask and clothing before the end of the trials. The subjective perceptions were rated on a continuous scale that ranged from 1 (very slight), 2 (slight), 3 (somewhat slight), 4 (moderate), 5 (somewhat strong), 6 (strong), and 7 (very strong). A 0 was also listed to represent not at all. The meanings of scale depended on the rated perceptions. 2.5 Statistical Analysis The average patterns of the uncomfortable sensations and the evaluation of overall satisfactory 631

11 level were analyzed by a two-factor analysis of variance with repeated measures (main effects were type of mask or clothing and time of day). A one-way ANOVA (type of mask or clothing) was performed on the evaluation of usability and overall preference. When a significant difference was obtained for a main effect, the multiple comparisons procedure by Bonferroni s method was used to identify specific differences. Relationships between variables were assessed by Pearson s correlation coefficients. Linear regressions were used to reveal the relationship between whole body and under the mask on thermal, wet and overall uncomfortable sensations. Multiple linear regression analyses (stepwise regression) were used to predict the factors affecting the overall uncomfortable sensations, satisfactory level and preference using all observations. All differences reported were regarded as significant at the p<0.05 level, and differences with 0.05<p<0.1 were referred to as a tendency in the data. 3. Results 3.1 Evaluation of Uncomfortable Sensations The perceived wetness and hotness in the mask and clothing are shown in Fig. 2. Both subjective ratings in the mask and clothing were significantly different between the types of PPE and time of day (p<0.001). The mean level of perceived wetness and hotness in the mask and clothing was significantly higher with PPE 1 and PPE 2 than with PPE 3, PPE 4 and PPE 5 (p<0.01), but not for hotness in the clothing with PPE 1 and PPE 2 vs with PPE 5. During the periods of two exercises, they were all judged to be moderate or over moderate with PPE 1 and PPE 2, and very slight with PPE 3, PPE 4 and PPE 5. The air-tightness of the mask and clothing is shown in Fig. 3. The air-tightness was significantly different between the types of PPE and time of day (p<0.001 for the mask and p=0.001 for the clothing). The mean level of perceived air-tightness in the mask and clothing was significantly higher with PPE 1 and PPE 2 than with PPE 3, PPE 4 and PPE 5 (p<0.01), but not for airtightness in the mask with PPE 1 and PPE 2 vs with PPE 3. During the periods of two exercises, the airtightness was judged to be near moderate or over moderate with PPE 1 and PPE 2, and very slight with PPE 3, PPE 4 and PPE 5. Fig. 2. Subjective ratings for perceived wetness and hotness in the mask (a and c) and clothing (b and d) under the influence of five different types of PPE. The values are means ± SEM (Standard Error of Mean) (n=10). The perceived prickliness in the mask and clothing is shown in Fig. 4. The perceived prickliness was significantly affected by the type of PPE (p<0.001) and by time of day (p<0.01). The mean perceived prickliness with PPE 1 and PPE 2 was significantly higher than with PPE 3, PPE 4 and PPE 5 (p<0.05), but there was no significant difference in the mask with PPE 1 vs with PPE 3. The perceived prickliness was judged to be below moderate with PPE 1, PPE 2, PPE 3, PPE 4 and PPE

12 PPE 3, PPE 4 and PPE 5 (p<0.05). The perceived unfitness in the mask was judged to be moderate with PPE 2 and PPE 3, and below moderate in the clothing with PPE 1, PPE 2, PPE 3, PPE 4 and PPE 5. Fig. 3. Subjective ratings for air-tightness of the mask (a) and clothing (b) under the influence of five different types of PPE. The values are means ± SEM (n=10). Fig. 5. Subjective ratings for perceived unfitness in the mask (a) and clothing (b) under the influence of five different types of PPE. The values are means ± SEM (n=10). Fig. 4. Subjective ratings for perceived prickliness in the mask (a) and clothing (b) under the influence of five different types of PPE. The values are means ± SEM (n=10). The perceived unfitness in the mask and clothing is shown in Fig. 5. The perceived unfitness was significantly affected by the type of PPE (p<0.001) and by time of day (p<0.001 for mask and p<0.05 for clothing). The mean perceived unfitness with PPE 2 and PPE 3 in the mask was significantly higher than with PPE 1, PPE 4 and PPE 5 (p<0.05), with PPE 1 and PPE 2 in the clothing was significantly higher than with Fig. 6. Subjective ratings for perceived fatigue in the mask (a), and perceived heaviness in the clothing (b) under the influence of five different types of PPE. The values are means ± SEM (n=10). Fig. 6, (a)-(b) shows the perceived fatigue in the mask and heaviness in the clothing. Both was significantly affected by the type of PPE and by time of day (p<0.001). The mean perceived fatigue in the mask with PPE 1 and PPE 2 was significantly higher than with PPE 3, PPE 4 and PPE 5 (p<0.05), but there was 633

13 no significant difference in the mask with PPE 1 vs with PPE 5. The mean perceived heaviness in the clothing with PPE 1, PPE 2 and PPE 5 was significantly higher than with PPE 3 and PPE 4 (p<0.05). The perceived fatigue in the mask was judged to be moderate or near moderate with PPE 1 and PPE 2, and be very slight in the clothing heaviness with PPE 1, PPE 2 and PPE 5, and not at all to very slight with PPE 3 and PPE 4. The perceived overall discomfort in the mask and clothing is shown in Fig. 7. The perceived overall discomfort was significantly affected by the type of PPE and by time of day (p<0.001). The mean perceived overall discomfort in the mask with PPE 1, PPE 2 and PPE 3 was significantly higher than with PPE 4 and 5 (p<0.05), and in the clothing with PPE 1 and 2 was significantly higher than with PPE 3, PPE 4 and PPE 5 (p<0.05). The perceived overall discomfort in the mask was judged to be moderate or over moderate with PPE 1, PPE 2 and PPE 3, and moderate or near moderate in the clothing with PPE 1 and PPE 2. Fig. 8. The subjective responses to the question on the difficulties in putting on and taking off the mask (a) and clothing (b). The values are means ± SEM (n=10). Fig. 7. Subjective ratings for perceived overall discomfort in the mask (a) and clothing (b) under the influence of five different types of PPE. The values are means ± SEM (n=10). Fig. 9 shows the interferences of vision and communication imposed by the mask, and interference of job performance imposed by the clothing. These interferences were significantly affected by the type of PPE (p<0.001). Visual and communicable interferences were judged to be over moderate to high in PPE 1 and PPE 2, and minimal in PPE 3, PPE 4 and PPE 5. The interference of job performance was judged to be significantly higher in PPE 1, PPE 2 and PPE 5 than in PPE 3 and PPE 4 (p<0.05). 3.2 Evaluation of Usability The subjective responses to the question on the difficulties in putting on and taking off the mask and clothing are presented in Fig. 8. These responses were significantly affected by the type of PPE (p<0.001). Putting on and taking off PPE 1 and PPE 2 were considered to be significantly more difficult than those of PPE 3, PPE 4 and PPE 5 (p<0.01). 634

14 (surgical mask) was the highest, and the clothing in PPE 3 (half-sleeved clothing) was the highest. Fig. 9. The interferences of vision and communication imposed by the mask, and interference of job performance imposed by the clothing. The values are means ± SEM (n=10). 3.3 Evaluation of Overall Satisfactory Level The perceived overall satisfactory level in the PPE ensemble is shown in Fig. 10. The perceived overall satisfactory level was significantly affected by the type of PPE and by time of day (p<0.001). The mean perceived overall satisfactory level with PPE 1, PPE 2 and PPE 3 ensembles was significantly lower than with PPE 4 and PPE 5 ensembles (p<0.01). PPE 4 and PPE 5 ensembles were judged to over moderate to high satisfactory level, and PPE 1, PPE 2 and PPE 3 ensembles were judged to moderate or below moderate satisfactory level. Fig. 10. The perceived overall satisfactory level in the PPE ensemble. The values are means ± SEM (n=10). 3.4 Subjective Preference Subjective preferences for the mask and clothing are shown in Fig. 11. The subjective preferences were significantly affected by the type of PPE (p<0.001). Subjective preference for the mask in PPE 4 and PPE 5 Fig. 11. The preferences of subjects for the mask and clothing. The values are means ± SEM (n=10). 3.5 Relationship between Air-Tightness and oher Uncomfortable Sensations An air-tightness increase of the mask and clothing had a significant augmenting effect (p<0.001) on the subjective perceptions of feeling humid (r=0.78 and 0.76), hot (r=0.82 and 0.78), prickly (r=0.70 and 0.73), unfit (r=0.64 and 0.75), and fatigued (r=0.81) for the mask and overall discomfort (r=0.78 and 0.84) respectively. 3.6 Relationship between Whole Body and uder the Mask Areas in terms of Thermal, Wet and Overall Sense of Discomfort Fig. 12 reveals the relationship between whole body and under the mask on thermal (a), wet (b) and overall discomfort (c). The perceptions of thermal (BTS), wet (BWS) and overall sensation of discomfort (BDS) in whole body were significantly correlated with those sensations (Mts, Mws and Mds) under the mask (R 2 =0.959, and 0.942, p<0.001, respectively). The ratings of local thermal, wet and overall discomfort sensations under the mask were higher, corresponding to those sensations in whole body. 3.7 The Subjective Factors Affecting Discomfort Sensation, Satisfactory Level, and Preference The following relationships between overall uncomfortable sensations under the mask (MDS) and in whole body, and overall satisfactory level in PPE 635

15 Whole body overall discomfort sensation Whole body wet sensation Whole body thermal sensation ensembles (ESL) and all observations were established by multiple linear regression analyses: MDS = Mws Mts Mas Mps Mufs Mo Miv Mic (R 2 = 0.822; df = 341, p<0.001) Eq.1 BDS = Bts Bas Bps Bufs (R 2 = 0.832; df = 345, p<0.001) Eq.2 ESL = Mds Bds (R 2 = 0.509; df = 347, p<0.001) Eq.3 Eq.1 revealed that perceived wetness, hotness (Mts), airtightness (Mas), prickliness (Mps), unfitness (Mufs), odor (Mo), and the interferences of vision (Miv) and communication (Mic) imposed by the mask significantly influenced MDS. The ratings of MDS showed significant augmentation along with increased Mws, Mts, Mas, Mufs, Mo and Mic. Out of them, the unfitness and odor induced by the mask were the most important factors affecting MDS. Eq.2 showed that perceived hotness (Bts), airtightness (Bas), prickliness (Bps) and unfitness (Bufs) significantly influenced the ratings of BDS. The Bts was the most important determinant of BDS. Eq.3 revealed that overall uncomfortable sensations both under the mask and in whole body (Bds) significantly influenced the overall satisfactory level in PPE ensemble. The Mds was a more important determinant of ESL. The decreased Mds and Bds increased ESL. 4. Discussion 4.1 Uncomfortable Sensations and Usability Associated with Wearing Different Protective Clothing Ensembles In this study, the PPE 1 and PPE 2 ensembles received significantly more ratings on the subjective perceptions feeling humid, hot, prickly, unfit in clothing, fatigued in mask and overall discomfort than the PPE 3, PPE 4 and PPE 5 ensembles (Fig. 2, 4, 5, 6 and 7). The subjective ratings of air-tightness also increased significantly with the PPE 1 and PPE 2 than with the PPE 3, PPE 4 and PPE 5 (Fig. 3). Unlike half-masks and separate gowns or apron without sleeves worn in the PPE 3, PPE 4 and PPE 5, in PPE 1, the facial protective equipment was a combination of a respirator and face shield, and the garment comprised a conventional, disposable and impermeable coverall with a hood. The PPE 2 garment comprised a newly designed 1-piece gown with a full facepiece and hood, and a mask was worn inside the gown. 1-piece garment constructions of PPE 1 and PPE 2 could contribute to their higher air-tightness, limiting sweat and heat dissipations from uncovered parts of the neck and face like in the PPE 3, PPE 4 and PPE 5. Moreover, studies found wearing a garment similar to the PPE 1 limited sweat evaporation, increased heat storage and contributed to heat strain [14,16,17]. (a) (b) 3.5 (c) y = x R 2 = Local thermal sensation under the mask y = x R 2 = Local wet sensation under the mask y = x R 2 = Local overall discomfort sensation under the mask Fig. 12. The relationship between whole body and under the mask on thermal (a), wet (b) and overall uncomfortable (c) sensations. 636

16 Furthermore, our physiological test showed a significant increase in core temperature and skin temperatures in PPE 1 and PPE 2 than in PPE 3, PPE 4 and PPE 5. Therefore, the subjects perceived the PPE 1 and PPE 2 ensembles as less favourable on thermal sensation and perception of moisture. Furthermore, the correlation analysis indicated that an air-tightness increase of the mask and clothing had a significant augmenting effect on the subjective perceptions feeling prickly, unfit, fatigued for the mask and overall discomfort, implying that higher airtightness in the PPE 1 and PPE 2 may also have been responsible for higher subjective ratings on other uncomfortable sensations. The PPE 1 and 2 received less favorable ratings than the PPE 3, PPE 4 and PPE 5 in terms of the difficulties in putting on and taking off the mask and clothing. Our results were close to those of Wang et al. [18] who found that putting on and taking off PPE 1 garment may be a complicated procedure as compared with conventional gowns similar to the PPE 4 and PPE 5 (tie at the back, without hood and trousers), because PPE 1 has more components with hood, zipper and trousers that has to be put on and taken off or be zipped. Moreover, both mask and facepiece in the PPE 1 and PPE 2 were separately put on or taken off. This procedure also increased difficulties and time. Farquharson and Baguley [19] reported that Emergency Department (ED) staff taking care of SARS patients at a hospital in Toronto wore double isolation gowns, a hair cap, an N95 mask, a face shield and two pairs of gloves. The ED staff experienced a challenge while finding a vein and taking blood with double gloves and a face shield, implying that a face shield may induce visual constraint. In the present study, the mean subjective scale responses on the vision and communication characterized the interferences as over moderate to high with both PPE 1 and PPE 2 with facepiece, which was in accordance with practical experience reported by Farquharson and Baguley [19]. In addition, the interference of job performance was judged to be significantly higher in PPE 1, PPE 2 and PPE 5 clothing than in PPE 3 and PPE 4 clothing. Heavier clothing of PPE 1, PPE 2 and PPE 5, as described by both the objective weight and subjectively perceived heaviness (Fig. 6b), could limit the wearer s activities and interfere the job performance. 4.2 Overall Satisfactory Level and Overall Preference Associated with Wearing Different Protective Clothing Ensembles The ratings of MDS showed significant augmentation along with increased Mws, Mts, Mas, Mufs, Mo and Mic (Eq. 1). The perceived Bts, Bas, Bps and Bufs significantly influenced the ratings of BDS (Eq. 2). While overall discomfort both under the mask and in the whole body significantly influenced the overall satisfactory level in PPE ensembles (Eq. 3). The subjective scales showed that the PPE 1 and PPE 2 were less appreciated than the PPE 3, PPE 4 and PPE 5 for individual and overall uncomfortable sensations, which resulted in significantly lower overall satisfactory level in both PPE 1 and PPE 2 ensembles (Fig. 10). However, the PPE 3 ensemble received a significantly less rating of overall satisfactory level than the PPE 4 and PPE 5, in spite of similar individual uncomfortable sensations among the PPE 3, PPE 4 and PPE 5. This could due to a higher unfitness in the mask of PPE 3 (Fig. 5a). Eq. 1 has shown that the unfitness induced by the mask was the most important factor affecting MDS, whereas the whole body overall discomfort was a linear function of local overall discomfort under the mask (Fig. 12), and MDS was a more important determinant of ESL compared with BDS (Eq.3). This result suggests that sometimes fitness of the mask is a more important factor affecting the overall uncomfortable sensation and satisfactory level compared with thermal or moisture perception under the mask. Therefore, it is necessary to modify Mask B and make it fit tightly on the subjects. Subjective preference belonged to the surgical masks worn in PPE 4 and PPE 5 (Fig. 11) because the surgical masks provided enhanced usability and reduced discomfort, fatigue and odor. PPE 3 clothing obtained subjective preference (Fig. 11). Its second lightest weight and the lowest perceived moisture (Fig. 2b) might have contributed to this. Li observed that the perception of comfort is negatively related to the perception of dampness [20]. Nielsen and Endrusick recommended the use of the subjective sensations of wetness of skin and clothing as a sensitive tool to evaluate the thermal function of garments [21]. The present study suggests that the subjective sensation of wetness of body skin is also an important index of the subjective preference. Moreover, the whole body sensation of wetness was a linear function of local sensation of wetness under the mask (Fig. 12), and the Mws was higher, the Bws was higher. It should be noted that although the PPE 1 and PPE 2 are less appreciated than the PPE 3, PPE 4 and PPE 5 for individual and overall uncomfortable sensations, and overall satisfactory level, the experiences of infection control for SARS have proved that a high protection provided by an ensemble similar to the PPE 637

17 1 is necessary under the outbreaks of serious infectious diseases [3, 19]. Since the uncomfortable sensations are mainly caused by the air-tightness of PPE, it is suggested that health care workers wearing PPE 1 and PPE 2 will require proper work and rest cycle so that health-care workers can remove the ensembles in an enclosed well ventilated room to release excess heat and humidity and to reduce the uncomfortable sensations during the rest periods. 5. Conclusion Results of this study show that when ensembles similar to PPE 1 and PPE 2 with face shield and hood are used in warm environments, the subjects receive less favorable subjective responses in terms of the uncomfortable sensations, usability, overall satisfactory level and preference. The uncomfortable sensations could be mostly explained by the air-tightness of PPE. The weight and construction may be responsible for the usability differences between PPE. The fitness of the mask is an important factor affecting the overall uncomfortable sensation under the mask and overall satisfactory level for PPE ensemble. It is suggested that the designer should make the mask fit tightly on the users. Subjective preference for the mask depends on enhanced usability and reduced discomfort, fatigue and odor. The subjective sensation of wetness of body skin is an important index of the subjective preference for the clothing. The whole body thermal sensation was significantly influenced by the local thermal sensation under the mask. For an ensemble providing high protection but with high air-tightness, the work schedule of proper work and rest cycle is suggested. Acknowledgements The authors would like to acknowledge the ITF/HKRITA for providing funding support to this research through project ITP/014/08TP and the Hong Kong Polytechnic University through project G-U027. References: [1] World Health Organization (WHO), Hospital Infection Control Guidance for Severe Acute Respiratory Syndrome (SARS). World Health Organization, Geneva. 24 April, [2] US Centers for Disease Control (CDC), Infection control in healthcare, home, and community settings. 8 January, [3] Seto WH, Tsang D, Yung RWH, Ching TY, Ng TK, Ho M, Ho LM. Effectiveness of precautions against droplets and contact in prevention of nosocomial transmission of severe acute respiratory syndrome (SARS). Lancet 2003;361: [4] Rengasamy A, Zhuang Z, BerryAnn R. Respiratory protection against bioaerosols: Literature review and research needs. The New England Journal of Medicine 2004;32: [5] Chen WT, Wu HDI, Lin CC, Cheng YC. Emergency Department Response to SARS, Taiwan. Emerging Infectious Diseases 2005; 11: [6] Lau JT, Fung KS, Wong TW, Kim JH, Wong E, Chung S, Ho D, Chan LY, Lui SF, Cheng A, SARS transmission among hospital workers in Hong Kong. Emerging Infectious Diseases 2003; 10: [7] Loeb M, McGeer A, Henry B, Ofner M, Rose D, Hlywka T, Levie J, McQueen J, Smith S, Moss L, Smith A, Green K, Stephen D, Walter SD. SARS among critical care nurses, Toronto. Emerging Infectious Diseases 2004;10: [8] Population and Public Heath Branch of Canada, Guidelines for Preventing the Transmission of Tuberculosis in Canadian Health Care Facilities and Other Institutional Settings: TB Management Program. 22s [9] Bentley RA, Griffin OG, Love RG, Muir DCF, Sweetland KF. Acceptable levels for breathing resistance of respiratory apparatus. Archives of Environmental Health 1973;27: [10] Nielsen R, Gwosdow AR, Berglund LG, DuBois, AB. The effect of temperature and humidity levels in a protective mask on user acceptability during exercise. American Industrial Hygiene Association J 1987;48: [11] Meyer JP, Héry M, Herrault J, Hubert G, François D, Hecht G, Villa M. Field study of subjective assessment of negative pressure half-masks. Influence of the work conditions on comfort and efficiency. Applied Ergonomics 1997;28: [12] White MK, Hodous TK, Vercruyssen M. Effects of thermal environment and chemical protective clothing on work tolerance, physiological responses, and subjective ratings. Ergonomics 1991;34: [13] White MK, Hodous TK, Hudnall JB. Physiological and subjective responses to working in disposable protective coveralls and respirators commonly used by the asbestos abatement 638

18 industry. American Industrial Hygiene Association J 1989;50: [14] Turpin-Legendre E, Meyer JP. Comparison of physiological and subjective strain in workers wearing two different protective coveralls for asbestos abatement tasks. Applied Ergonomics 2003; 34: [15] Turpin-Legendre E, Meyer JP. Comparison of physiological and subjective strains of two protective coveralls in two short physically simulated demanding tasks. Applied Ergonomics 2007; 38: [16] White MK, Hodous TK. Reduced work tolerance associated with wearing protective clothing and respirators. American Industrial Hygiene Association J 1987;48: [17] Holmer I, Nilsson H, Rissanen S, Hirata K, Smolander J. Quantification of heat balance during work in three types of asbestos-protective clothing. Int. Arch. Occup. Environ. Health 1992;64: [18] Wong TKS, Chung JWY, Li Y, Chan WF, Ching PTY, Lam CHS, Chow CB, Seto WH. Effective personal protective clothing (PPC) for healthcare workers attending patients with severe acute respiratory syndrome (SARS). American Journal of Infection Control 2004;32: [19] Farquharson C, Baguley K. Responding to the severe acute respiratory syndrome (SARS) outbreak: lessons learned in a Toronto emergency department. Journal of Emergency Nursing 2003;23; [20] Li Y. Perceptions of temperature, moisture and comfort in clothing during environmental transients. Ergonomics 2005;48: [21] Nielsen R, Endrucisk TL. Sensations of temperature and humidity during alternative work/rest and the influence of underwear knit structure. Ergonomics 1990;33:

19 Effects of Clothing Wicking and Moisture Management Characteristics on Perception of Breathable-airtight Jiao Jiao, Lei Yao, Ka-Wai Lau, Yi Li * Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong, China * Corresponding author s address: tcliyi@polyu.edu.hk Abstract: This paper investigates the influence of specific properties of clothing namely wicking and moisture management on sensory response in neutral and hot conditions. Wicking and moisture management properties of clothing were tested and identified. Then double blind cross over wearing trials were conducted to study the subjective sensory response in different environmental conditions. A total of 10 male subjects participated in the wear tails. Two garments, long sleeved top and long pants made from hydrophilic and hydrophobic polyester were used in the wear trials. The subjects were asked to rest in a neutral zone (Temperature 20 C, R.H. 50%) for 30 minutes, followed by a stay in a hot zone (Temperature 30 C, R.H. 80%) for another 20minutes, and further 10minutes of walking in the hot zone (Temperature 30 C, R. H. 80%). Questionnaires on sensory comfort levels, which include questions regarding clammy, breathable, damp, cool, prickly and soft were completed by the subjects during each trial. The results suggest that clothing properties of wicking and moisture management seem to have played an important role on sensory response, especially in terms of wearers comfortable perception of Breathable-Airtight. Keywords: wicking, moisture management, hydrophilic, sensory response, Breathable-airtight 1. Introduction Nowadays more and more research is undertaken to develop fabrics that provide comfort to wearers. Researchers have attempted to explain the relationship between comfort and clothing [1,2]. There is a general agreement that wearing Comfortable ensures a state of sensory efficiency from the skin to the brain, which transfers into subjective perception of people about the clothing they wear [3,4]. Clothing comfort is strongly affected by physical properties of fabric such as surface structure, water-vapor permeability and air permeability [5]. Various technologies such as hydrophilic treatments can be manipulated to change fabric properties, which are particularly aimed to make synthetic fabric more hydrophilic. The treated synthetic fabric is perceived to be favorable and breathable especially in humid and hot environment. Work on clothing comfort and treatments were previously concerned with the fabric itself and the physiological response of subjects [6]. However, there are only a few psychological studies focused on specific properties of fabrics with hydrophilic treatment such as wicking and moisture management, and indeed more information regarding subjects sensory response to such fabrics is needed. The objective of this research is to investigate whether knitted polyester fabrics, with and without hydrophilic treatments, exert significant influence on the physical properties of fabrics, especially in terms of wicking and moisture management characteristics, and if these properties, in turn, significantly affect subjective sensory perceptions. In general, the relationship between clothing physical properties and sensory responses of subjects will be investigated through objective measurement instruments and subjective questionnaire responses. 2. Methods 2.1 Experimental Materials Two lengths of white colored double-pique knitted polyester fabrics with 12.8 courses per cm and 12.4 wales per cm were treated with hydrophobic (Fabric A) and hydrophilic (Fabric B) agents in the experiment. A variety of methods were used to determine the physical properties of the fabrics. The standards used for physical property test of fabrics are provided in Table 1. In order to maximize the contact area of skin with the fabrics, garments with full cover style, long sleeves and pants, were designed for the wear trials. doi: /tbis

20 2.2 Experimental Protocol Subjects Ten healthy male subjects aged 21.8±1.04 years with body mass index (BMI) 21±1.67 were recruited in this study. The general purpose, procedures and risks were fully explained and written consent was obtained from all the subjects. The subjects were required to refrain from alcohol and any vigorous physical activity for 24hours before each trial Trial Design The experiments were carried out in two different environments: (1) temperature (T) 20±1 and relative humidity (R.H.) 50±5 %; (2) T 30±1 and R.H. 80±5 %. All the trials were arranged from 10:00-12:30 in the morning. At the first stage, the subjects entered the artificial environments with a controlled temperature of 20 and R.H.50%, and they changed into experimental garments. When the trial started, subjects were asked to answer two sensory perception questionnaires at 0 and 30 minutes time points (shown in Fig. 1). During the 30 minutes, subjects stayed peacefully and were given the opportunity to gain equilibrium with the environment. Then, subjects rested in the climatic chamber with the temperature 30 and R.H. 80% for 30 minutes, and walked on a treadmill at the speed of 4 km/hour for 10 minutes which was aimed to simulate a sense of a common daily activity in summer. Sensory questionnaires were completed on the time points, 31minutes, 50 minutes and 60 minutes. The principle of the timing the questionnaire response at 31 st minute was to obtain the first psychological perception when the subject entered the contrasting environment; questionnaire completion at the 50 th minute stage was to acquire the sensory response when subjects had gained a sense of equilibrium with the environment; and the aim of questionnaire at the 60 th minute duration was to gain the responses regarding sensory perception after subjects engaged in physical activity and perspired, a scenario that had been improvised to influence the sensory perception [7]. After walking, the last sensory perception questionnaire was completed at the first instance when subjects went back to the environment of temperature 20 and R.H. 50% again Questionnaire Fig. 1. Protocol of wear trial. During the whole experiment, the questionnaires with non-comparative unbalance and force rating scales were used (Fig. 2 & 3). In the questionnaire, the sensory perceptions could be simply classified into two categories of: (a) Thermal-wet comfort, which could be further elaborated with perceptions of Clammy-Dry; Sticky-Smooth; Breathable-Airtight; Damp-Dry; Heavy-Light; Cool-Hot, and (b) mechanical comfort: in terms of Scratchy-Smooth; Itchy-Smooth; Prickly-Smooth; Rough-Smooth; Soft-Stiff. The sensory perceptions could be correlated to the physical properties of the fabric for further evaluation of the relationship between subjective and objective measurements. The scale of questionnaire suggested by Li [8] were chosen on the basis of the fact that, under testing conditions, subjects were unlikely to feel cold on the thermal scale, and the rating scale for clammy sensation could only be neutral to extreme points. Also, thermal and clammy sensations were such fundamental perceptions that subjects were expected to respond to the item with a high degree of certainty. Fig. 2. Sensory perception of clammy-dry. Fig. 3. Sensory perception of cool-hot. 641