Effect of Palm Cooling with Negative Pressure on Heat Balance During Exercise in a Hot, Dry Environment
Abstract
Military personnel often must work in hot environments, increasing the risk of hyperthermia. Our purpose was to evaluate a new rapid thermal exchange device (RTX) in slowing the development of hyperthermia and associated symptoms to 3 other conditions [hand immersed in water bath (WB), water-perfused vest (VEST), and a no- cooling condition (NC)] in subjects exercising in a hot environment (42C, 30% rh) wearing summer fatigues, a backpack and body armor. Ten subjects (age 25+/-3 yrs; weight 74+/-6 kg) performed 4 heat stress tests in a counter-balanced order (NC/RTX/WB/ VEST) The protocol consisted of two bouts of treadmill walking (at 50% VO2max), separated by a 41-min cooling and rehydration period. The time to reach a pre-determined rectal temperature (Tr) in the 1st and 2nd bouts were not different among RTX (mean +/- SD; 52+/-14 and 42+/-l2 min respectively), NC (49+/-13 and 4l+/-14 min respectively), and WB (54+/-14 and 55+/-20 min respectively), but was longer for the VEST (85+/-30 and 65+/-12 min respectively) in both bouts (p<0.05). The Trslope (C/min) was significantly lower for VEST in the 1st and 2nd bouts versus the other conditions (p<0.05). HR was not different at 10,20 and 30 minutes of exercise in the 1st bout among RTC, NC, and WB, but was lower for VEST in the 1st bout (p<0.05). HR was not different among conditions in the 2nd bout. Therefore, the RTX (unit B) was not effective in slowing the development of hyperthermia in the present protocol. Aspects related to hand vasoconstriction and the severe work/heat stress conditions possibly prevented the expected heat extraction.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 15, 2006
- Accession Number
- ADA459500
Entities
People
- Fabiano Amorium
- Paulette Yamada
- Rob Robergs
- Steve Verney
- Suzanne Schneider
Organizations
- University of New Mexico