Simulated human thermoregulatory responses to events of a cold wet sea rescue

Time limit estimates for safe recovery following water mishaps were assisted by human simulation. In this case, warfighters starting from an assumed neutral state, entered outside conditions (10-20°C with winds of 5-20 km/h) before entering the water (13-18°C). After swimming to the raft they climbed aboard and remained there in wet clothing until rescued. In the cold water, body heat loss is rapid and independent of simulated physiological fitness and cardiovascular differences. Once on the raft their thermal state depended strongly on environmental conditions and the ability to sustain shivering thermo-genesis. Core temperatures measured with radio pills from 20 warfighters during a cold wet windy sea rescue training exercise for 7.5 hours compare well with simulated values.