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How Hypothermia Affects Most Adults
Time to Exhaustion or
Estimated Survival Time
0.3 (32.5) <15 min <15-45 min
0.3-4 (32.5-40) 15-30 min 30-90 min
4-10 (40-50) 30-60 min 1-3 hrs
10-16 (50-60) 1-2 hrs 1-6 hrs
16-21 (60-70) 2-7 hrs 2-40 hrs
21-27 (70-80) 2-12 hrs 3 hrs to indefinite
>27 (80) indefinite indefinite
PFDs can increase survival time because they allow you to float without using energy treading
water and because of their insulating properties. Naturally, the warmer the water, the less
insulation you will require. When operating in cold waters [below 60°F (15.6°C)] you should
consider using a coat or jacket style PFD or a Type V Thermal Protective PFD as they cover
more of the body than the vest or belt style PFDs.
Some points to remember about hypothermia protection:
1. Always wear your Inflatable PFD. Even if you become incapacitated due to hypothermia,
the Inflatable PFD will keep you afloat and greatly improve your chances of rescue.
2. Do not attempt to swim unless it is to reach a nearby craft, fellow survivor, or a floating
object on which you can lean or climb. Swimming increases the rate of body heat loss.
In cold water, drown-proofing methods that require putting your head in the water are
not recommended. Keep your head out of the water. This will greatly lessen heat loss and
increase your survival time.
3. Use the standard H.E.L.P. position when wearing an Inflatable PFD, drawing the legs up
to a seated position, because doing so will help you conserve body heat (Figure 33).
4. Keep a positive attitude about your survival and rescue.
This will improve your chances of extending your
survival time until rescued. Your will-to-live does make a
5. If there is more than one person in the water, huddling
is recommended while waiting to be rescued. This action
tends to reduce the rate of heat loss and thus increase the
MD3188 Inflatable PFD Manufacturer's Manual