Quick Answer
Hypothermia can set in as quickly as 10-15 minutes in cold water, depending on air temperature, water temperature, and clothing. In 50-degree Fahrenheit (10-degree Celsius) water, a person can lose up to 95% of their body heat in the first 30 minutes. Even with a properly fitting PFD, the risk of hypothermia remains high.
Exposure to Cold Water
When a boat sinks, the immediate priority is to stay afloat. Treading water is essential to conserve energy and maintain a stable body temperature. To tread water, alternate kicking your legs and using your arms to help you stay afloat. This technique is particularly effective when done in a square or circular motion.
Rescue Position and Hypothermia Prevention
Assuming you have a properly fitting PFD, position yourself in a vertical flotation position to maximize visibility and reduce the risk of hypothermia. Keep your head and body out of the water as much as possible to minimize heat loss. In extremely cold water, hypothermia can set in more quickly, so it’s essential to find a way to stay warm.
Staying Warm in Cold Water
To stay warm in cold water, focus on using your body’s natural insulation. Cross your arms to trap warm air next to your skin, and bring your knees up to your chest to conserve heat. If you have a hat or other floating debris, use it to cover your head, as up to 60% of body heat can be lost through the head. In cold water, hypothermia can be fatal if not addressed promptly.
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