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Matsunami, M1; Taimura, A1; Sugawara, M1

Medicine & Science in Sports & Exercise: May 2003 - Volume 35 - Issue 5 - p S29
A-15O Free Communication/Poster Heat Stress and Dehydration

1Beppu Women's Junior College, Oita; Faculty of Environmental Studies, Nagasaki Univ.; Faculty of Education Nagasaki Univ., Japan


Swimmers wear two types of swim caps – the waterproof type and non-waterproof type. Which type to choose often depends upon each swimmer's preference.

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To examine whether the difference in the material of swim caps varies body temperature in swimming.

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Ten male competitive swimmers (age 20.0±-1.3yr, body weight 66.2±-6.3kg, %Fat 18.4±-3.2%) performed sub-maximal 20-minutes swimming in a 25m indoor pool (room; 28.7±-1.4 water; 28.8±-0.4 using the front crawl stroke wearing either a waterproof silicone cap (SC) or a non-waterproof mesh cap (MC). Forehead skin temperature (Tfh) and occipital temperature (Toc) and heart rate (HR) were measured throughout the swimming. Tympanic (Tty) and oral (Toral) temperature were measured prior to and after each swim. Rating of perceived exertion (RPE), and perceived thermal sensation of head (TSH) and body (TSB) were measured on completion of the trials.

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Measurement after the trial showed significant differences in Tfh (SC: 33.70±-0.82 MC: 32.45±- 0.69), Toc (SC: 30.85±-1.18 MC: 28.95±-0.55) and TSH (SC: 6.7±-0.8, MC: 5.6±-0.8) resulting from wearing the different types of swim caps. However, there were no significant differences between SC and MC in Toral, Tty and TSB. Regarding the changes in Tfh and Toc during the trial, they both declined during the first five minutes and then, except for Toc in MC, assumed an upward curve; Toc in MC didn't rise, but kept stable from after the first five minutes to the last.

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The results showed that the difference in the material of swim caps caused changes in the cephalic surface temperature and a thermal sensation on the head, and that the waterproof swim cap had the property of obstructing heat dissipation by conduction. Furthermore, it was assumed that the waterproof swim cap could affect the oral and tympanic temperature according as water temperature and exercise intensity rose.

©2003The American College of Sports Medicine