To examine the effect of whole body pre-cooling on the exercise duration and the thermoregulatory and metabolic responses during the exercise, fourteen male runners (27 $\pm$ 7.4 yrs) completed two separate high-intensity running test sessions. Each session consisted of a rest period in either 24$\sp\circ$C (normothermic condition; NC) or 5$\sp\circ$C air (hypothermic condition; HC) for 30 minutes followed by an exercise bout at 82% of individual maximal aerobic capacity to exhaustion. / Rectal temperature was significantly lower (0.37$\sp\circ$C) in HC than in NC when subjects started exercise. Rectal, mean skin, and mean body temperatures remained lower during the exercise in HC compared to NC (ANOVA). The exercise duration in HC (26 min. 14 sec.) was significantly longer and equivalent of 121 $\pm$ 23.9% to the duration in NC (22 min. 25 sec.). The change between post- and pre-exercise values in mean skin, mean body, thermal gradient as well as heart rate was larger in HC compared to NC (t-test, p $<$ 0.05). On the other hand, the final value of rectal temperature, thermal gradient, and heart rate was not different between the two conditions. While exercising, a greater increase in heat storage was observed in HC (173 $\pm$ 45.7 W$\cdot$m$\sp{-2}$) than in NC (143 $\pm$ 38.1 W$\cdot$m$\sp{-2}$) and subjects lost larger amounts of sweat in NC than in HC. Oxygen consumption was significantly lower in an early phase of HC than in NC while oxygen pulse and respiratory exchange ratio were not different. Blood lactate level at post-exercise was not different between the conditions. Based on the results, it is concluded that whole body pre-cooling increases the duration of high-intensity running in a thermoneutral environment. Greater endurance is accompanied by less stress in thermoregulatory and cardiovascular systems as well as greater thermal capacitance after pre-cooling. / Source: Dissertation Abstracts International, Volume: 55-08, Section: B, page: 3180. / Major Professor: Emily M. Haymes. / Thesis (Ph.D.)--The Florida State University, 1994.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77223 |
| Contributors | Lee, Dae Taek., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 245 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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