The dangers of hypothermia might not have been on the minds of four men as they set out on a fishing trip on a sunny, warm Saturday in the Gulf of Mexico. But it is now one of the most threatening factors in the survival of the three still lost at sea.
Hypothermia, the reduction of the body's temperature below the point of normal functioning, can happen much more quickly in water than in air. People immersed in water 70 degrees or colder lose body heat 100 times faster than they would in air of the same temperature.
A person in 80-degree water could survive indefinitely. But drop the temperature 10 degrees and exhaustion or unconsciousness can occur in less than a day. In 50- to 60-degree water, the expected survival time is one to six hours.
The temperature in the gulf at the time that Marquis Cooper, Corey Smith, Will Bleakley and Nick Schuyler were submerged after their boat tipped Saturday night dropped to about 60 degrees, experts estimate. Schuyler pulled himself on top of the flipped boat, where he shivered in a life vest for hours until the Coast Guard rescued him. Schuyler told rescuers that the other three slipped away sometime before he was found.
Factors that can help combat cold
Body size: The body temperature for an overweight person drops slower than for a thin person, and children cool faster than adults.
Physical fitness: Well-conditioned people are better able to handle the cardiovascular stress of cold-water immersion. However, body fat is a good thing, as the insulation helps fend off hypothermia.
Clothing: Synthetic fibers are better than cotton, which can actually draw heat out of the body when it's wet. A hat or cap can trap warmth in your head, where 75 percent of body heat is lost. If nothing else, keep vital organs, such as the heart and lungs, covered.
Body position: While it may seem like a good idea to stay moving to keep your body temperature up, it's best to keep your arms at your sides and knees together to conserve as much heat as possible.
Stages of hypothermia at various grades of body temperature:
98.6 degrees Fahrenheit: Normal body temperature
95 F: Hypothermia. First symptoms: Paleness, drowsiness, listlessness, mental confusion, armpits and abdomen cold.
93 F: Loss of memory, movements slow and are hard, hands can no longer hold things.
91 F: Shaking stops, the body gives up; unconsciousness, 50 percent chance of survival.
90 F: Heart may stop; 30 percent chance of survival.
68-77 F: Heart stops.