P.12
HYPOTHERMIA
Prolonged exposure to cold water causes a condition known as
hypothermia – a substantial loss of body heat which leads to exhaustion
and unconsciousness. Most drowning victims first suffer from
hypothermia. The following chart shows the effects of hypothermia:
HOW HYPOTHERMIA AFFECTS MOST ADULTS
Exhaustion or
Unconsciousness
Expected Time
of Survival
UNDER 15 to 45 MIN
30 to 90 MIN
1 to 3 HOURS
1 to 6 HOURS
2 to 40 HOURS
3 HOURS to INDEFINITE
INDEFINITE
UNDER 15 MIN
15 to 30 MIN
30 to 60 MIN
1 to 2 HOURS
2 to 7 HOURS
2 to 12 HOURS
INDEFINITE
0.3 (32.5)
0.3 to 4 (32.5 to 40)
4 to 10 (40 to 50)
10 to 16 (50 to 60)
16 to 21 (60 to 70)
21 to 27 (70 to 80)
over 27 (over 80)
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
water (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 PFD. Even if you become incapacitated due to hypothermia,
the 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 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.
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 difference!
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 survival time.
Water Temperature
C (F)
