CHAPTER 4: Emergency Preparedness
COLD WATER IMMERSION: PHYSIOLOGICAL RESPONSE
When a person falls into cold water, their body experiences a variety of physiological responses that relate both to the temperature of the water and the amount of time they are in contact with the water. When immersed in cold water, the body goes through the following stages.
It only takes a few minutes for your body to start losing basic motor skills when immersed in cold water. After as little as three minutes, you may start to lose strength and sensation in your hands, which will also affect your ability to swim, regardless of how good a swimmer you are. Boaters often drown as a result of swimming failure even before hypothermia has had the chance to set in.
LONGER TERM IMMERSION
After about 30 minutes of cold-water immersion, the body’s core temperature will drop below the safe normal level. This is called hypothermia. The core temperature will continue to drop until it has reached the same temperature as the water, and the person will lapse into unconsciousness.
THE FINAL STAGE: POST-RESCUE COLLAPSE
A drop in blood pressure resulting from hypothermia may cause the person to become unconscious, or even stop breathing, even several hours after the rescue. For this reason, a person suffering from hypothermia needs to receive medical attention as soon as possible following rescue from the water.
A PERSON SUFFERING FROM HYPOTHERMIA SHOULD RECEIVE MEDICAL ATTENTION AS SOON AS POSSIBLE