Popis: |
The effects of simulated interior lifeboat environments on the thermoregulatory responses of participants wearing immersion suits were investigated. Two different environmental conditions were investigated: the interior air temperature and relative humidity levels found in a conventional lifeboat that relies on passive ventilation (“Condition 1”); and those proposed to be in a next generation lifeboat that will have an active ventilation system (“Condition 2”). Participants performed three hour tests in both Condition 1 and Condition 2. Condition 1 produced a significantly greater increase (P < 0.05) in the rate of sweat accumulation, rate of mean skin temperature and gastro-intestinal temperature increase, heart rate, and physiological strain index values compared to Condition 2. Condition 1 caused an amount of sweat accumulation sufficient to dampen the underclothing to a level that would cause a significant reduction in predicted survival time. Heart rate, gastro-intestinal temperature and physiological strain index values continued to rise during Condition 1 suggesting that the level of thermal stress was uncompensable by the thermoregulatory systems of the participants which is supported by the air temperature and relative humidity levels being at a critical environmental limit in which heat balance cannot be achieved. It is concluded that the interior environmental conditions of conventional lifeboats that rely on a passive ventilation system will result in a level of thermal stress that cannot be compensated for by people wearing immersion suits which will result in increasing levels of physiological strain. |