2007, Piran, Slovenia
2007, Piran, Slovenia 2007, Piran, Slovenia
Environmental Ergonomics XII Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007 DISCUSSION Physical work load and climatic stress (especially for HTT in a climatic chamber) were kept constant for all exposures; in spite of this the intra-individual variation of data is surprisingly high. Most data look quite normally distributed (as seen in Figure 1). As an explanation of the great variation in increase of Tre we hypothesise that the extension of body core versus body shell may be different at the beginning of the different exposures, thereby varying the resulting heat capacity of the body with respect to a given increase of core temperature. As there was no correlation between Tre at the start and the end of MRST, no prognosis can be made from the starting value for the outcome of the training. REFERENCES Kampmann, B., Bresser, G., Piekarski, C., 1996. Individual parameters influencing tolerance time of mine rescue team members in the heat. In: Environmental Ergonomics. Recent Progress and New Frontiers (Y. Shapiro, D.S. Moran, Y. Epstein), Freund Publishing House, London, 385-388. Kampmann, B., Bresser, G., Piekarski, C., 1997. Stress and strain of mine rescue teams during a standard training procedure. Appl. Occup. Environ. Hyg. 12.12, 952-956. Kampmann, B., Bresser, G., 2005. Habituation to a complex working task in the heat: mine rescue training. In: Proceedings of the 11 th International Conference on Environmental Ergonomics (Holmér, I., Kuklane, K., Gao, C.) 520-523. 406
Acute and chronic heat exposure HAND IMMERSION IN COLD WATER ALLIVIATES HEAT STRAIN Gennadi Khomenok, Amir Hadid, Ran Yanovich, Tomer Erlich, Osnat Ron-Tal, Amir Peled, Yoram Epstein, and Daniel S. Moran Heller Institute of Medical Research, Sheba Medical Center, Tel Hashomer and the Sackler Faculty of Medicine, Tel Aviv University, ISRAEL Contact person: dmoran@sheba.health.gov.il INTRODUCTION Exercising in the heat increases physiological strain, an effect further exacerbated by wearing protective garments. To alleviate heat strain, several strategies can be applied including modifying work/rest cycles and the use of microclimate cooling devices. Microclimate cooling devices have proven to be effective, but there are operational and logistic situations that prevent the routine implementation and use of such cumbersome and energy dependant devices. The present study was conducted to investigate the efficiency of alleviating heat strain by periodic immersion of hands in cold water. METHODS Seventeen healthy, young volunteers aged 18–28 years (24 ±0.6 y, 1.77 ±0.09 m, 68.1 ±9.4 kg) participated in this study. The study protocol was thoroughly explained to them and they approved their participation by signing a proper consent form, and the protocol was approved by the Institutional Human Use Committee.Wearing a semi-permeable NBC protective garment (DUROSHIELD) and a bulletproof Kevlar vest, the participants were exposed twice for 125 min to a controlled environment of 35°C and 50% relative humidity. Exercise consisted of walking (treadmill) at a 5 km⋅hr -1 and 5% incline, and included: 5 min sitting rest followed by 2 sessions of 50:10 min work-rest cycles. A crossover study was designed where in one exposure participants immersed their hands during both rest periods in cold water of 10°C (Hand Immersion group) and the other exposure was with no cooling (Control group). During the exposures, the volunteers' body core temperature (Tre), skin temperature (Tsk), and heart rate (fc) were continuously monitored and sweat rate was calculated for the entire period. RESULTS The results are summarized in Figures 1-2. The physiological strain was lessened by periodic hand immersion in cold water. Tre was reduced during the hand immersion exposures by 0.43 ∆Trec (°C) 0.6 0.5 0.4 0.3 0.2 0.1 0.0 * n=17 n=17 1 1 2 st Rest 55 min 2 nd Rest 115 min Time (min) * n=17 n=12 P
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Acute and chronic heat exposure<br />
HAND IMMERSION IN COLD WATER ALLIVIATES HEAT STRAIN<br />
Gennadi Khomenok, Amir Hadid, Ran Yanovich, Tomer Erlich, Osnat Ron-Tal,<br />
Amir Peled, Yoram Epstein, and Daniel S. Moran<br />
Heller Institute of Medical Research, Sheba Medical Center, Tel Hashomer and the Sackler<br />
Faculty of Medicine, Tel Aviv University, ISRAEL<br />
Contact person: dmoran@sheba.health.gov.il<br />
INTRODUCTION<br />
Exercising in the heat increases physiological strain, an effect further exacerbated by wearing<br />
protective garments. To alleviate heat strain, several strategies can be applied including<br />
modifying work/rest cycles and the use of microclimate cooling devices. Microclimate<br />
cooling devices have proven to be effective, but there are operational and logistic situations<br />
that prevent the routine implementation and use of such cumbersome and energy dependant<br />
devices. The present study was conducted to investigate the efficiency of alleviating heat<br />
strain by periodic immersion of hands in cold water.<br />
METHODS<br />
Seventeen healthy, young volunteers aged 18–28 years (24 ±0.6 y, 1.77 ±0.09 m, 68.1 ±9.4<br />
kg) participated in this study. The study protocol was thoroughly explained to them and they<br />
approved their participation by signing a proper consent form, and the protocol was approved<br />
by the Institutional Human Use Committee.Wearing a semi-permeable NBC protective<br />
garment (DUROSHIELD) and a bulletproof Kevlar vest, the participants were exposed<br />
twice for 125 min to a controlled environment of 35°C and 50% relative humidity. Exercise<br />
consisted of walking (treadmill) at a 5 km⋅hr -1 and 5% incline, and included: 5 min sitting rest<br />
followed by 2 sessions of 50:10 min work-rest cycles. A crossover study was designed where<br />
in one exposure participants immersed their hands during both rest periods in cold water of<br />
10°C (Hand Immersion group) and the other exposure was with no cooling (Control group).<br />
During the exposures, the volunteers' body core temperature (Tre), skin temperature (Tsk), and<br />
heart rate (fc) were continuously monitored and sweat rate was calculated for the entire period.<br />
RESULTS<br />
The results are summarized in Figures 1-2. The physiological strain was lessened by periodic<br />
hand immersion in cold water. Tre was reduced during the hand immersion exposures by 0.43<br />
∆Trec (°C)<br />
0.6<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0.0<br />
*<br />
n=17<br />
n=17<br />
1 1 2<br />
st Rest 55 min<br />
2 nd Rest 115 min<br />
Time (min)<br />
*<br />
n=17<br />
n=12<br />
P
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