Water Exposure

• Your body cools at least 32 times faster in water than in cold air. The impact of cold water can have a dramatic effect on your body, stressing it immediately, from the first breath to the quick onset of numbness in your extremities. In frigid temperatures, your chances of survival shrink from hours to minutes based on how long you stay in the water. Because mild hypothermia can set in at water temperatures of 70 degrees, get out of the water as soon as possible once you show signs of hypothermia.
  
  

Levels of Hypothermia

• The minute you begin shivering uncontrollably, mild hypothermia has set in. This stage lasts until your core temperature has dropped to 96 degrees. Moderate hypothermia occurs when your body temperature falls to between 93 and 95 degrees. You will be dazed and confused, your speech will slur and you will begin to make irrational decisions, such as trying to take off clothes. Your motor skills will be compromised. Body temperatures of 86 to 92 degrees indicate severe hypothermia and an immediate life-threatening emergency.
  
  

Survival in the Water

• Staying in the water causes your body to lose heat at a much higher rate. Your best chance of survival is getting out of the water immediately. If you've fallen into the water, try to get back into your boat or to dry land as quickly as possible. If your boat capsized, get on top of it to reduce your exposure to the water. If you're not alone, huddle with another person in the water to preserve heat.
  
  

Swim or Tread Water

• If you're alone in the water with no assistance, you have two choices. You can swim to safety or tread water waiting for your rescue. Swimming is the more proactive choice, but you will lose precious body heat faster. This can shorten your chance of survival by more than 50 percent. How long you can survive treading water depends on how cold the water is.
  
  

Survival Expectancy

• At water temperatures between 70 and 80 degrees, exhaustion or unconsciousness begins to set in after 3 to 12 hours. Your survival time is 3 hours to indefinitely. At water temperatures between 60 and 70 degrees, your time until exhaustion or unconsciousness is 2 to 7 hours, with an expected survival time in the water of 2 to 40 hours. Water temperatures between 50 and 60 degrees give you 1 to 2 hours until exhaustion or unconsciousness sets in, with an expected survival time in the water of 1 to 6 hours. More dangerous temperatures between 40 and 50 degrees allow for 30 to 60 minutes before exhaustion or unconsciousness sets in, with an expected survival time in the water of 1 to 3 hours.
  
  

Immediate Danger

• At water temperatures between 32.5 and 40 degrees, you only have 15 to 30 minutes until you experience exhaustion or unconsciousness. At this point, your expected survival time in the water is only 30 to 90 minutes. Anything below 32 degrees is an imminent threat. You can lose consciousness in less than 15 minutes and die in 45 minutes or less.