Georgia Boater Education Course


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.

INITIAL IMMERSION OR COLD WATER SHOCK

When a person first falls into cold water, their initial reaction will be a “gasp reflex”. This reflex often includes hyperventilationWhen breathing becomes much faster and/or deeper than normal, resulting in the loss of carbon dioxide from the blood, leading to various negative effects such as a decrease in blood pressure, fainting, etc. and muscle spasms, and, as a result of gasping for air, can lead to the inhalation of water. It can also lead to changes in heart rate and blood pressure. These first effects usually last about two to three minutes at which point the body starts to experience more serious changes.

SHORT-TERM IMMERSION

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.

Short-term immersion

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.

Immersion Hypothermia

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