Combined effects of fabric air permeability and moisture absorption on clothing microclimate and subjective sensation during intermittent exercise at 27 degrees C

Clothing impact on post-exercise comfort: skin-clothing physiology in transient environment

Sportswear manufactured from hygroscopic fibres can absorb moisture during activity or intermittent exercise and may change the thermal management of clothing. This change in the thermal behaviour of the fabric can lead to buffer the post-exercise chill. During activity in a moderately cold environment clothing made of 100% wool fibre helps wearers to slow down evaporative and conductive cooling, which can provide more thermal and comfort sensation compared to 100% cotton, 100% viscose, and 100% polyester. Twelve males performed cycling in a controlled climate chamber of temperature: 15 ± 0.5 °C, and relative humidity (RH):50 ± 5% followed by a drying phase in a windy environment by wearing full-sleeve t-shirts. Wool shirt was observed to hold a greater torso skin temperature (p < 0.05) than the other fibre types. Participants were asked a range of comfort-related questions at varying intervals. The temperature sensation was found (p < 0.05) significant for wool clothing. Moreover, participants rated wool shirt significantly (p < 0.05) as more comfortable during the post-exercise phase.

Effect of sportswear on performance and physiological heat strain during prolonged running in moderately hot conditions

INTRODUCTION

This study examined the impact of different upper-torso sportswear technologies on the performance and physiological heat strain of well-trained and national-level athletes during prolonged running in moderately hot conditions.

METHODS

A randomized crossover design was employed in which 20 well-trained (n = 16) and national-level (n = 4) athletes completed four experimental trials in moderately hot conditions (35°C, 30% relative humidity). In each trial, participants ran at 70% of their peak oxygen uptake (70% V̇O2peak ) for 60 min, while wearing a different upper-body garment: cotton t-shirt, t-shirt with sweat-wicking fabric, compression t-shirt, and t-shirt with aluminum dots lining the inside of the upper back of the garment. Running speed was adjusted to elicit the predetermined oxygen consumption associated with 70% V̇O2peak . Physiological (core and skin temperatures, total body water loss, and urine specific gravity) and perceptual (thermal comfort and sensation, ratings of perceived exertion, and garment cooling functionality) parameters along with running speed at 70% V̇O2peak were continuously recorded.

RESULTS

No significant differences were observed between the four garments for running speed at 70% V̇O2peak , physiological heat strain, and perceptual responses (all p > 0.05). The tested athletes reported larger areas of perceived suboptimal cooling functionality in the cotton t-shirt and the t-shirt with aluminum dots relative to the sweat-wicking and compression t-shirts (d: 0.43-0.52).

CONCLUSION

There were not differences among the tested garments regarding running speed at 70% V̇O2peak , physiological heat strain, and perceptual responses in well-trained and national-level endurance athletes exercising in moderate heat.

Effect of different garments on thermophysiological and psychological comfort properties of athletes in a wear trial test

This paper reports on an experimental investigation of thermophysiological and psychological responses during and after an incremental low- to high-intensity exercise at 27 °C and 45% humidity. Five t-shirt garments were produced from different yarn types, their weights and yarn counts were close to each other. During the wear trials, heat and humidity sensors were placed at four body locations (the chest, back, abdomen, and waist). In addition, dynamic comfort measurements of the upper body were examined using a datalogger and subjective rating scales. This study aimed to investigate the effects of garment type on aerobic performance, microclimate temperature and humidity values, and psychological comfort. It was observed that the relative humidity and temperature of the microclimate were low in fabrics with high air permeability and low thermal resistance values of the Tencel single jersey and polyester mesh knitted fabrics. There was a significant difference in microclimate temperature results of TS coded Tencel single jersey t-shirt sample and other t-shirt samples according to statistical analysis results. On the other hand, the statistical results of the PM coded fabric sample measured at lower humidity in the three body regions were found to be a significantly different from those of the other samples (except TS). Although not statistically significant, the VO2 values and heart rates of these fabrics were lower than those of other fabrics. It was concluded that garments made from Tencel single jersey (TS) and polyester mesh (PM) fabrics affected the performance of athletes positively. Athletes were less forced during the training, and the activity could be maintained more than the others when wearing these clothes.

The Role of Sports Clothing in Thermoregulation, Comfort, and Performance During Exercise in the Heat: A Narrative Review

The aims of this review are to (1) summarise the current research of sports clothing as it relates to thermoregulation, comfort, and performance during exercise in the heat, (2) identify methodological limitations and gaps in the knowledge base of sports clothing, and (3) provide recommendations for exercise testing protocols to accurately assess the impact of sports clothing in athletic populations during exercise in the heat. Sports clothing consists of lightweight and breathable fabrics, surface treatments, and various designs which aim to enhance sweat evaporation and comfort during exercise in the heat. Sports clothing comprised of natural, synthetic, and chemically treated fabrics has been investigated during exercise of varying durations (15–120 min), intensities (20–70% VO₂ max) and types (fixed intensity, incremental, self-paced), and in an array of climatic conditions (18–40 °C, 20–60% relative humidity). To date, few studies have identified significant differences in thermo-physiological, perceptual, and performance measures between natural and synthetic fabrics or compared the effect of chemical treatments to their non-treated equivalent on such measures during exercise. Collectively, previous wearer trials have failed to replicate the upper limit of training and competition demands when assessing sports clothing in endurance-trained individuals who regularly train and compete in hot and humid climates. Clothing comfort has also been evaluated using simple scales which fail to capture intricate detail pertaining to psychological and sensorial parameters. The incorporation of protocols using hot and humid climates (≥ 30 °C, ≥ 70% relative humidity) and longer exercise durations (> 45 min) is warranted. Future research should also consider exploring the effect of sports clothing on thermal, physiological, perceptual, and performance measures between males and females, and assessing clothing comfort using a multi-dimensional approach.

Factors Affecting the Thermal Comfort of Perioperative Personnel in the OR

Thermal comfort is an important component of any work setting and can be difficult to achieve in the complex OR environment. This comparative descriptive study sought to identify factors affecting the thermal comfort of perioperative personnel in the OR (N = 68). Researchers used the American Society of Heating, Refrigerating and Air-Conditioning Engineers Thermal Sensation Scale and researcher-developed surveys to collect data. The mean reported thermal comfort level was -0.44 (standard deviation 1.3), which is within acceptable parameters. Factors affecting thermal comfort were gender, professional role, and wearing additional clothing. Additionally, participants who complained about temperature or ventilation were less likely to report thermal comfort levels in the normal range. Health care facility leaders should consider the comfort needs of perioperative personnel when making purchasing decisions about ventilation systems and surgical clothing; however, they also should consider other factors (eg, surgeon comfort, permeability of protective clothing to blood and other body fluids).

Physiological and Psychological Responses during Exercise and Recovery in a Cold Environment Is Gender-Related Rather Than Fabric-Related

We evaluated gender-specific effects of two types of undergarments on exercise-induced physiological and psychological stress and subsequent recovery in cold conditions for male and female participants. Ten healthy men and eleven healthy women (25.0 ± 1.5 versus 23.4 ± 1.2 years old, respectively) completed the experimental session twice with two different types of undergarments: polyester or merino wool leggings and long-sleeve tops; specifically, merino fabric had greater thermal resistance and water absorbency, and less water vapor as well as air permeability than polyester. Experimental sessions involved performing 1 h of exercise on a cycle ergometer at 8°C ambient temperature and 55% relative humidity, holding at 70-80 revolutions per minute and 60% of each participant's predetermined maximal power output (assessed by maximal oxygen uptake test), followed by 1 h recovery in the same environment. Every 5 min during exercise and every 10 min during recovery, rectal temperature, heart rate, subjective ratings for thermal, shivering/sweating and clothing wetness sensations, and clothing next-to-skin and outer side surface temperature and humidity on the chest, back and thigh were recorded. All participants experienced high physiological stress (assessed by physiological strain index) during exercise. No significant gender differences were found in core temperature or heart rate changes during exercise, but women cooled down faster during recovery. Next-to-skin humidity was similar between genders and different garment sets during exercise and recovery, but such temperatures at the chest during exercise and at the thigh during exercise and recovery were lower in women with both sets of garments. Subjective thermal sensations were similar in all cases. In the last 20 min of cycling, women started to feel wetter than men (P < 0.05) for both garment sets. Shivering was reported as stronger in women in the last 10 min of recovery. Most of the changes in the garment microclimates during exercise and recovery in the cold were associated with gender-related differences rather than with fabric-related differences.

Influence of Clothing on Thermoregulation and Comfort During Exercise in the Heat

Davis, JK, Laurent, CM, Allen, KE, Zhang, Y, Stolworthy, NI, Welch, TR, and Nevett, ME. Influence of clothing on thermoregulation and comfort during exercise in the heat. J Strength Cond Res 31(12): 3435-3443, 2017-Sport textiles of synthetic fiber have been proposed to have superior properties for keeping wearers cooler, drier, and more comfortable compared with natural fibers. The impact of various fiber content and fabric construction on thermoregulation and perceptual responses are not well understood. Eight male collegiate athletes performed 3 counterbalanced trials of 45-minute treadmill run at 60% of maximal oxygen uptake in an environmental chamber (32° C). Three different fibers, consisting of 100% cotton, a blend of natural fibers (50/50% cotton/soybean), and a synthetic fiber (100% polyester) with mesh loops to facilitate ventilation through the clothing, were tested. Heat strain indices, microenvironment temperature, ratings of perceived exertion (RPE), and clothing comfort were measured. Session RPE (S-RPE) and session thermal sensation (S-TS) were recorded 20 minutes after each trial. There was no effect of clothing on rectal, skin, and body temperatures, heart rate, RPE, or comfort measures (p ≥ 0.05). A significant effect was observed for synthetic fiber compared with cotton on S-RPE (p = 0.03), S-TS (p = 0.04), and the microenvironment temperature at the chest (p = 0.02). No significant difference was shown for any other fibers on S-RPE, S-TS, or other microenvironment areas (p ≥ 0.05). These results show that clothing fiber content and fabric construction had no effect on thermoregulation, RPE, or clothing comfort during moderate-intensity exercise in the heat; whereas synthetic fabric construction indeed effectively reduced regional microenvironment temperature and attenuated global exertion and TS, which may have important implications for exercise tolerance in the heat.

Does wearing clothing made of a synthetic "cooling" fabric improve indoor cycle exercise endurance in trained athletes?

This randomized, double-blind, crossover study examined the effects of a clothing ensemble made of a synthetic fabric promoted as having superior cooling properties (COOL) on exercise performance and its physiological and perceptual determinants during cycle exercise in ambient laboratory conditions that mimic environmental conditions of indoor training/sporting facilities. Twenty athletes (15 men:5 women) aged 25.8 ± 1.2 years (mean ± SEM) with a maximal rate of O₂ consumption of 63.7 ± 1.5 mL·kg⁻¹·min⁻¹ completed cycle exercise testing at 85% of their maximal incremental power output to exhaustion while wearing an ensemble consisting of a fitted long-sleeved shirt and full trousers made of either COOL or a synthetic control fabric (CTRL). Exercise endurance time was not different under COOL versus CTRL conditions: 12.38 ± 0.98 versus 11.75 ± 1.10 min, respectively (P > 0.05). Similarly, COOL had no effect on detailed thermoregulatory (skin and esophageal temperatures), cardiometabolic, ventilatory, and perceptual responses to exercise (all P > 0.05). In conclusion, clothing made of a synthetic fabric with purported “cooling” properties did not improve high-intensity cycle exercise endurance in trained athletes under ambient laboratory conditions that mimic the environmental conditions of indoor training/sporting facilities.

Novel ventilation design of combining spacer and mesh structure in sports T-shirt significantly improves thermal comfort

This paper reports on novel ventilation design in sports T-shirt, which combines spacer and mesh structure, and experimental evidence on the advantages of design in improving thermal comfort. Evaporative resistance (Re) and thermal insulation (Rc) of T-shirts were measured using a sweating thermal manikin under three different air velocities. Moisture permeability index (i(m)) was calculated to compare the different designed T-shirts. The T-shirts of new and conventional designs were also compared by wearer trials, which were comprised of 30 min treadmill running followed by 10 min rest. Skin temperature, skin relative humidity, heart rate, oxygen inhalation and energy expenditure were monitored, and subjective sensations were asked. Results demonstrated that novel T-shirt has 11.1% significant lower im than control sample under windy condition. The novel T-shirt contributes to reduce the variation of skin temperature and relative humidity up to 37% and 32%, as well as decrease 3.3% energy consumption during exercise.

The effects of a moisture-wicking fabric shirt on the physiological and perceptual responses during acute exercise in the heat

This study investigated the effects that a form fitted, moisture-wicking fabric shirt, promoted to have improved evaporative and ventilation properties, has on the physiological and perceptual responses during exercise in the heat. Ten healthy male participants completed two heat stress tests consisting of 45 min of exercise (50% VO2peak) in a hot environment (33 °C, 60% RH). One heat stress test was conducted with the participant wearing a 100% cotton short sleeved t-shirt and the other heat stress test was conducted with the participant wearing a short sleeved synthetic shirt (81% polyester and 19% elastane). Rectal temperature was significantly lower (P < 0.05) in the synthetic condition during the last 15 min of exercise. Furthermore, the synthetic polyester shirt retained less sweat (P < 0.05). As exercise duration increases, the ventilation and evaporation properties of the synthetic garment may prove beneficial in the preservation of body temperature during exercise in the heat.

Impact of clothing on exercise in the heat

Clothing targeting the exercise enthusiast has been advertised to keep individuals drier, cooler, and more comfortable during exercise in the heat. The marketing of such clothing has increased dramatically within the last decade. In hot environments, clothing acts as a barrier to thermal balance by inhibiting evaporative and convective cooling. Clothing construction, fit, and fabric are all critical influences on the amount of sweat absorbed from the skin and transported throughout the clothing. The majority of the research analyzing advertised synthetic fabrics has shown no difference in thermoregulation or clothing comfort while exercising in those fabrics in the heat compared to natural fabrics. The influence of clothing construction on thermal balance has received minimal research in regards to exercise. Further research is needed in this area, since it is poorly understood from ecologically valid human testing. Future research should also consider examining the effects of clothing characteristics on comfort during exercise and recovery. The incorporation of protocols that more closely mirror sporting and recreational activity lasting >60 min as well as simulated work-related protocols lasting >120 min is warranted.

Exercising in a hot environment: which T-shirt to wear?

OBJECTIVE

The aim of this study was to investigate thermoregulatory, cardiorespiratory, metabolic, and perceptual responses while running in a hot environment (31.7° ± 1.0°C; 42% ± 3% relative humidity) and wearing T-shirts made from different fiber types.

METHODS

Eight well-trained men performed 4 tests wearing either a T-shirt made of 100% polyester with 4, 6, or 8 channels, or one made of 100% cotton. Each test consisted of 30 minutes running at 70% of peak oxygen uptake, followed by a ramp test to exhaustion and 15 minutes of recovery.

RESULTS

There were no differences in skin, core, and body temperatures between fiber types during submaximal and high-intensity running (best P = .08). During recovery, body temperature and shivering/sweating sensations were lower when wearing 4- and 6-channel fibers (P ≤ .04) compared with cotton. The relative humidity at the chest and back were lower for all polyester T-shirts compared with cotton during and after submaximal and maximal running (P ≤ .007). Heart rate (best P = .10), oxygen uptake (P = .95), respiratory exchange ratio (best P = .93), ventilation (best P = .99), and blood lactate concentration (best P = .97) did not differ between the fiber types. Nor were any differences in time to exhaustion (best P = .76), ratings of perceived exertion (best P = .09), thermal sensation (best P = .07), or sensation of clothing wetness (best P = .36) discovered.

CONCLUSIONS

Although statistical analysis revealed lower shivering/sweating sensations while wearing 4- and 6-channel fiber shirts during recovery, with an improved chest and back microenvironment for all polyester T-shirts, the question remains whether these differences are of any practical relevance because the performance of the well-trained men was unaffected.

The effect of two kinds of T-shirts on physiological and psychological thermal responses during exercise and recovery

The aim of this study was to investigate the physiological and psychological responses during and after high-intensity exercise in a warm and humid environment in subjects wearing shirts of different fabrics. Eight healthy men exercised on two separate occasions, in random order, wearing two types of long-sleeve T-shirt: one made of polyester (PES) and the other of cotton fabric (CT). They performed three 20 min exercise bouts, with 5 min rest between each, and then rested in a chair for 60 min to recover. The ambient temperature was 25 °C and relative humidity was 60%. The exercise comprised of treadmill running at 8 km/h at 1° grade. Rectal temperature, skin temperatures at eight sites, heart rate, T-shirt mass and ratings of thermal, clothing wettedness, and shivering/sweating sensation were measured before the experiment, during the 5 min rest period after each exercise bout, and during recovery. Nude body mass was measured before the experiment and during recovery. The physiological stress index showed that the exercise produced a state of very high heat stress. Compared with exercise wearing the CT shirt, exercise wearing the PES fabric produced a greater sweating efficiency and less clothing regain (i.e., less sweat retention), but thermophysiological and subjective sensations during the intermittent high-intensity exercise were similar for both fabrics. However, skin temperature returned to the pre-exercise level faster, and the thermal and rating of shivering/sweating sensation were lower after exercise in the warm and humid environment in subjects wearing PES than when wearing the more traditional CT fabric.