Simulated Human Responses to Transient Cold Wet Sea Exposure Sequences
Abstract
The risks of hypothermia were estimated by human simulation modeling for a sea rescue scenario in various cold to cool conditions. The Warfighters were assumed to be wearing a battle dress uniform (BDU) or similar clothing. The exposure sequence started from a resting neutral comfortable thermal state. They then entered the outside air conditions for 15 minutes before entering the water. After 15 minutes in the water they climbed on to a wet raft that contained about a foot of seawater sloshing about and remained there for up to 24 hours before being rescued. Simulations of the human responses to these events were made for a 13 deg C sea temperature with air temperatures (Ta) of 10, 15, and 20 deg C and wind velocities (Va) of 5, 10, and 20 km/h. Further simulations where made to estimate the effect if any of physiological fitness and of elevated activity levels before reaching the raft. The results indicate that in the 13 deg C water, body heat loss is rapid and at the point of climbing on to the raft the thermal physiological state is fairly independent of activity, physiological fitness and cardiovascular differences. Once on the raft the progression of Warfighters' thermal state depended strongly on the Ta and Va, and their ability to shiver and sustain it. The simulation model estimates reported here compare favorably with core temperature measurement of 20 persons during a 7.5 hour sea and wet raft exposure in 20 deg C air.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2002
- Accession Number
- ADA405126
Entities
People
- Daniel S. Moran
- Larry G. Berglund
- Richard R. Gonzalez
- Yuval Heled
Organizations
- United States Army Research Institute of Environmental Medicine