environmental considerations monique mokha, phd, …...international journal of athletic therapy...
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international journal of athletic therapy & training november 2011 9
Physiologic effects of prolonged exposure to a hot or cold environment can have a negative impact on body temperature and exercise performance and could predispose an athlete to injury.1,2 The maintenance
of body temperature in hot or cold condi-tions is dependent on the balance between heat production from metabolism, heat gain from the environ-ment, and the loss of heat by conduction, convection, radiation, and evaporation.3,4 In recent years, mois-ture wicking materials have been promoted by clothing manufac-turers to assist in the regulation of body temperature during exercise in both hot and cold environ-ments.5,6 Manufactur-ers claim that moisture wicking garments can
keep individuals cooler and more comfort-able while exercising in hot environments. With regard to cold weather garments, some claim that clothing can keep the individual
Monique Mokha, PhD, ATC, Report Editor
Effect of Moisture-Wicking Garments on Temperature Regulation During Exercise
ENVIRONMENTAL CONSIDERATIONS
Taz H. Kicklighter, MS, ATC; Jason R. Edsall, MEd, ATC, CSCS; and Malissa Martin, EdD, ATC, CSCS • Rocky Mountain University of Health Professions
warm in cold environments by wicking sweat away from the body, thereby allowing the wearer to feel warm and dry. Claims of moisture-wicking qualities have led to multi-million dollar sales in apparel for exercise clothing companies (Table 1). The purpose of this report is to review the current literature pertaining to perceptions and physiologic responses attributable to moisture-wicking material worn during exercise in hot and cold environments.
Garment Material CharacteristicsClothing design and fit influence an indi-vidual’s decision to wear particular articles of clothing during exercise.7 A garment that alters gait or perception of a “hob-bling” or “frictional drag” effect can deter the individual from wearing temperature-appropriate clothing.3 These factors have
© 2011 Human Kinetics - IJATT 16(6), pp. 9-13
Maintenance of body temperature in hot or cold conditions is dependent on the balance between metabolic heat production, heat gain from the environment, and the loss of heat by conduction, convection, radiation, and evaporation.
Exercise clothing is a multi-billion dollar per year industry that produces form-fitting, moisture-wicking clothing that has evolved from simple cotton shirts and shorts to garments comprised of polyester and elastane/spandex fabrics.
Manufacturers’ claim that such garments make individuals warmer and drier in cold environments and cooler and drier in warm environments are not supported by the existing evidence.
Key PointsKey Points
Table 1. 2010 SEC Reporting of Apparel
Revenue FiguresNike® $1.7 billion
Under Armour® $853 million
Adidas® $535 million
Champion®* $1.3 million*2009 revenue figures. Starter apparel figures not available.
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led manufacturers to produce form-fitting, moisture-wicking garments that are fabricated from polyester and elastane (also referred to as spandex) fabrics. These lightweight fabrics decrease the volume of cloth-ing material an individual must wear during activity, thereby decreasing weight and bulk and theoretically decreasing caloric expenditure during exercise. Poly-ester and elastane/spandex are the most popular fab-rics used in exercise clothing, due to their lightweight properties, durability, and ability to wick moisture away from the skin.8 Elastane/spandex, also known by the brand name Lycra®, has elastic properties that can be used to fabricate a compression garment that conforms closely to skin contours while transporting sweat to the outer surface of the garment, thereby facilitating evaporation.8 Elastane/spandex has qualities that can increase the strength, durability, and shape retention of a garment. Tables 2 and 3 illustrate fabric composi-tion of popular moisture-wicking garments for hot and cold environments.
Garments for Exercise in a Hot Environment
The National Athletic Trainers Association recommends wearing moisture-wicking materials while exercising in hot environments to prevent heat illnesses.6 Recent research supports the claim that clothing fabric type
can influence skin and core temperature in hot environ-ments. Havenith et al.9 measured the evaporative heat loss on a thermal manikin wearing permeable, semi-permeable, and impermeable full-body jumpsuits. At 10–34˚C and 80% relative humidity, their results dem-onstrated that the impermeable material produced a significantly greater surface temperature than the other materials. Kwon et al.10 had subjects ride cycle ergom-eters at 40% VO2 max for 6, 10-minute sessions in a 30º C and 50% relative humidity environment. Rectal temperatures were significantly lower for individuals exercising in cotton/wool blended materials than those who exercised in 100% cotton or 100% polyester mate-rials. Skin temperatures were significantly greater for subjects wearing 100% polyester compared to 100% cotton or the cotton/wool blend material. The results of this study contradict the common belief that mois-ture-wicking materials (i.e., 100% polyester) reduce skin and core temperatures when exercising in a hot environment. Both the Haventih et al.9 and Kwon et al.10 studies had subjects dressed in full-length pants and long-sleeve shirts, which is not typical exercise apparel for a hot environment. The research evidence that currently exists does not support moisture-wicking exercise apparel having a significant beneficial effect on body temperature nor the perception of coolness during exercise in a hot environment, as claimed by apparel manufacturers.2,11
Table 2. Fabric Composition of Common Hot Weather Shirts
Heat Resistant Clothing Fiber TypeNike® Dri-fit 100% polyester
Nike® Dri-fit UV 100% polyester double piqué
Under Armour® UA Tech 95% 4.6oz polyester/5% elastane
Under Armour® Heat Gear 81% 5oz polyester/19% elastane
Under Armour® Battle Gear81% 5oz polyester/19% elastane Mesh: 81% 5oz polyes-ter/19% elastane
Starter short sleeve compression tee Cationic polyester, spandex
Russell® dri-power tee 100% polyester
Champion® double dry short sleeve tee 100% polyester
Champion® double dry compression tee 84% polyester/ 16% spandex
Adidas® Techfit powerweb compression tee 75% nylon/25% spandex
Adidas® Clima365 tee 100% polyester interlock
international journal of athletic therapy & training november 2011 11
Gavin et al.2 had subjects run on a treadmill at 70% VO2 max in 30˚C and 35% relative humidity in three clothing conditions: (a) no shirt, (b) cotton t-shirt, and (c) synthetic, moisture-wicking t-shirt. For all three conditions, subjects wore spandex compres-sion shorts, polyester blend socks, and running shoes. Their results indicated that the synthetic fiber shirt promoted evaporation, but there were no significant differences in rectal temperatures or the perception of comfort between the conditions. Details about the composition of the synthetic material were not pro-vided. A study conducted by Brazaitis et al.11 involved a series of 20-minute, high-intensity treadmill running sessions, with 5-minute rest intervals, in a controlled environment at 25°C and 60% relative humidity. Sub-jects wore either a cotton or polyester-blend long-sleeve tee shirt. Their results indicated that neither rectal temperature nor perception of comfort were signifi-cantly different between the two clothing conditions during activity or at rest. Further research is needed to establish the effects of moisture-wicking garments on the regulation of body temperature and perception of comfort while exercising in a hot environment.
Garments for Exercise in a Cold Environment
To date, no research has been published that docu-ments the effects of various types of moisture-wicking fabrics on body temperature during exercise in a cold environment; however, clothing construction has been shown to affect thermoregulation during and follow-ing exercise in cold conditions.3,12,13 Meinander and Hellsten14 and Meinander et al.15 recommended that ideal winter clothing for a dry, cold condition should block air movement but allow for water vapor to escape through the clothing when sweating occurs. A variety of factors can affect the insulation value of clothing, including wind speed, body movement, chimney effect, bellows effect, water vapor transfer, and perme-ation efficiency factor.16,17 Individual preference should also be taken into consideration when choosing cloth-ing for exercise in a cold environment, because every person perceives warmth and cold differently. During competition, constant body movement can maintain body temperature and a perception of comfort in a cold environment. A decrease in the level of activity,
Table 3. Base Layer Clothing Sold as “Cold Resistant” by Their Respec-tive Manufacturer and the Composition of Each Garment
Cold Resistant Clothing Fiber TypeUnder Armour Cold Gear® fitted mock/leggings 89% polyester/11% elastane
Under Armour Cold Gear® tactical mock/leggings 66% nylon 19%/polyester/15% elastane
Under Armour Cold Gear® subzero mock/leggings 82% cationic polyester/18% elastane
Under Armour Cold Gear® “original” and combat long sleeve compression mock/leggings
63% nylon/23% polyester/14% elastane
Nike® pro combat hyperwarm fitted mock neck 92% polyester/8% spandex
Nike® pro combat core fitted 84% polyester/16% spandex
Nike® pro core tight mock neck training shirt Body (solid): 84% polyester/16% spandex Body (heather): 45% polyester/ 39% nylon/16% spandex
Adidas® Techfit powerweb long tights 75% nylon/25% elastane tricot
Adidas® Techfit preparation long sleeve 74% polyester/19% nylon/7% elastane
Adidas® Supernova sequence long sleeve 95% polyester/5% elastane
Champion® double dry cold-weather compression shirt/tights
88% polyester/12% spandex
Champion® double dry ultimate shirt/tights 94% polyester/6% spandex
Therramar long sleeve crew pullover 100% filament silk
12 november 2011 international journal of athletic therapy & training
such as half-time intermission, player substitution, and conclusion of competition can quickly produce a change in temperature perception.18 A decrease in metabolic heat production will occur, while radiant, convective, and conductive heat loss continue, thereby resulting in a rapid change in the perception of cold upon cessation of activity.
Clothing manufacturers produce garments from a wide variety of fabrics, each of which is claimed to provide greater benefit than similar items produced by competitors for maintenance of body temperature and comfort during exercise in cold weather. Two studies conducted by Li, Tokura, and Midorikawa19,20 found no significant difference in thermoregulation or sensation of warmth when exercising in single-layer wool versus nylon garments and no significant differ-ence for single-layer cotton versus nylon garments. These findings suggest that no single fabric should be recommended as superior to another for clothing worn during exercise in a cold environment.
Comparison of Garments for Exercise in Cold vs. Hot Environments
The similarity of fabric composition for apparel intended for use in hot weather versus cold weather should be noted by the consumer. Almost all of the garments promoted for use in both environments consist of 80-100% polyester and 0-20% elastane/spandex fibers. For example, the Champion® “double dry hot-weather compression tee” consists of 84% polyester and 16% elastane/spandex, whereas the “double dry cold-weather compression” shirt consists of 88% polyester and 12% elastane/spandex. Similarly, Under Armour® “Heat gear” consists of 81% polyester and 19% elastane/spandex, whereas its “cold gear”
consists of 82% polyester and 18% elastane/spandex. Nearly identical fabric distributions are found in hot and cold weather garments produced by most of the major exercise clothing manufacturers (Tables 2 & 3). The currently available research evidence does not support claims that an specific fabric composition has a significantly different effect on body temperature than others.2,9-13,17-18 Furthermore, there is no evidence that the sleeve length of a garment with a particular fabric composition affects body temperature in either hot or cold environments.2,9-13,17-18 Further research is needed to identify the optimal fabric composition for maintenance of body temperature within a desirable range during exercise in either hot or cold environ-ments. Such research is needed to independently confirm or refute the claims of “athletic gear” manu-facturers concerning garment performance in hot and cold environments. Recommendations for the type of fabric to wear during physical activity in hot and cold environments that are based on the available research evidence are presented in Tables 4 and 5.
Conclusions and RecommendationsExercise garments that are fabricated from polyester and elastane/spandex materials are widely marketed and utilized by athletes. Their form-fitting and mois-ture-wicking properties are appealing to consumers, but the available research evidence suggests that characteristics do not have a significant effect on body temperature or perception of comfort during exercise in hot or cold environments. Manufacturers’ claims that such garments can make individuals warmer and drier in cold environments, and cooler in warm envi-ronments, have yet to be substantiated by published research evidence.
Table 4. Recommendations for the Types of Fabric for Each Layer of Clothing Worn During Exercise in Hot
Environments and Their Characteristics2,9-11
Recommended Fabric Fabric CharacteristicsPolyester
Fabrics that do not readily absorb moisture but wick moisture to the outer layers where it can evaporate. Fabrics are semipermeable, potentially allowing for increased heat loss from skin due to convection.
Lycra
Elastane
Nylon
Spandex
international journal of athletic therapy & training november 2011 13
References 1. Li Y, Alshaer H, Fernie G. Blood pressure and thermal responses to
repeated whole body cold exposure: effect of winter clothing. Eur J Appl Physiol. 2009;107(6):673-685.
2. Gavin TP, Babington JP, Harms CA, Ardelt ME, Tanner DA, Stager JM. Clothing fabric does not affect thermoregulation during exercise in moderate heat. Med Sci Sports Exerc. 2001;33(12):2124-2130.
3. Gavin TP. Clothing and thermoregulation during exercise. Sports Med. 2003;33(13):941-947.
4. Fukazawa T, Lee G, Matsuoka T, Kano K, Tochihara Y. Heat and water vapour transfer of protective clothing systems in a cold environment, measured with a newly developed sweating thermal manikin. Eur J Appl Physiol. 2004;92(6):645-648.
5. Armstrong LE, Epstein Y, Greenleaf JE, et al. American College of Sports Medicine position stand. Heat and cold illnesses during distance running. Med Sci Sports Exerc. 1996;28(12):i-x.
6. Binkley HM, Beckett J, Casa DJ, Kleiner DM, Plummer PE. National Athletic Trainers’ Association Position Statement: exertional heat ill-nesses. J AthTrain. 2002;37(3):329-343.
7. Jussila K, Valkama A, Remes J, Anttonen H, Peitso A. The effect of cold protective clothing on comfort and perception of performance. Int J Occup Saf Ergon. 2010;16(2):185-197.
8. http://www.fabrics-manufacturers.com. 2010. Accessed 1/1/2011.
9. Havenith G, Richards MG, Wang X, et al. Apparent latent heat of evaporation from clothing: attenuation and “heat pipe” effects. J Appl Physiol. 2008;104(1):142-149.
10. Kwon A, Kato M, Kawamura H, Yanai Y, Tokura H. Physiological significance of hydrophilic and hydrophobic textile materials during intermittent exercise in humans under the influence of warm ambient temperature with and without wind. Eur J Appl Physiol. 1998;78(6):487-493.
11. Brazaitis M, Kamandulisa S, Skurvydasa A, Daniusevic̆iu_te. L. The effect
of two kinds of T-shirts on physiological and psychological thermal responses during exercise and recovery Appl Ergon. 2010;42(1):46-51.
12. Nielsen B. Solar heat load: heat balance during exercise in clothed subjects. Eur J Appl Physiol Occup Physiol. 1990;60(6):452-456.
13. Meinander H, Hellsten M. The influence of sweating on the heat trans-mission properties of cold protective clothing studied with a sweating thermal manikin. Int J Occup Saf Ergon. 2004;10(3):263-269.
14. Meinander H, Hellsten M. The influence of sweating on the heat trans-mission properties of cold protective clothing studied with a sweating thermal manikin. Int J Occup Saf Ergon. 2004;10(3):263-269.
15. Meinander H, Anttonen H, Bartels V, et al. Manikin measurements versus wear trials of cold protective clothing (Subzero project). Eur J Appl Physiol. 2004;92(6):619-621.
16. McCullough EA, Eckels S, Harms C. Determining temperature ratings for children’s cold weather clothing. Appl Ergon. 2009;40(5):870-877.
17. Griefahn B, Forsthoff A. Technical note. Comparison between esti-mated worn clothing insulation and required calculated clothing insulation in moderately cold environments (0 degree C < or = ta < or = +15 degrees C). Appl Ergon. 1997;28(4):295-299.
18. Meinander H, Anttonen H, Bartels V. Manikin measurements versus wear trials of cold protective clothing (Subzero project). Eur J Appl Physiol. 2004;92(6):619-621.
19. Li X, Tokura H, Midorikawa T. The effects of two types of clothing on sea-sonal cold tolerance. Eur J Appl Physiol Occup Physiol. 1994;69(6):498-501.
20. Li X, Tokura H, Midorikawa T. The effects of two different types of cloth-ing on seasonal cold acclimation of thermophysiological responses. Int J Biometeorol. 1994;38(1):40-43.
Taz H. Kicklighter is assistant athletic trainer and Clinical Coordinator for the Lee University Athletic Training Education Program and doctoral student at Rocky Mountain University of Health Professions.
Jason R. Edsall is assistant athletic trainer and head strength coach for Seton Hill University and doctoral student at Rocky Mountain University of Health Professions.
Malissa Martin is Associated Dean, professor, and graduate program director of the PhD in Athletic Training at Rocky Mountain University of Health Professions.
Table 5. Recommendations for the Types of Fabric for Each Layer of Clothing Worn During Exercise in Cold
Environments and Their Characteristics12-13,1-18
Recommended Fabric Fabric Characteristics
Inner LayerPolyester
Fabrics that do not readily absorb moisture but wick moisture to the outer layers where it can evaporate.
Lycra
Elastane
Nylon
Spandex
Silk
Polypropylene
Middle LayerWool Fabrics that allow moisture transfer to outer
layers and provide the primary insulation to the athlete.
Fleece
Polyester
Outer LayerWool Fabrics that allow moisture transfer to the air
while repelling wind and rainNylon