No matter whether you paddle a kayak, canoe, or SUP, there is always some risk that you may capsize. If the temperature of the water is less than 70°F, paddlers need to be aware of the serious risks that go along with falling into water that cold. Cold water can kill an unprepared paddler within minutes or even seconds of capsizing, but how can that be?
Believe it or not, hypothermia, or the lowering of the body’s core temperature, is not the most likely cause of death when someone drowns very soon after a capsize. The most immediate concern when someone capsizes into cold water is something called the cold water gasp reflex, also referred to as the cold shock response. When a person not wearing thermal protective clothing (like a wetsuit or drysuit) unexpectedly falls into water that is less than 70°F, that person will automatically gasp. If the person’s head is under water when experiencing that gasp reflex, she/he will likely inhale water into the lungs resulting in immediate drowning. The other possibility is that a person falling into cold water without appropriate clothing can potentially experience cardiac arrest which would also cause death. Cardiac arrest is more likely to occur in older people who may have some degree of advancing heart disease, but it can happen to younger people, as well.
Assuming that cardiac arrest has not occurred and that the person’s head was not underwater when experiencing the gasp reflex, the next stage of this cold shock response is hyperventilation. Normally, this stage of hyperventilation should only last a short time, a minute or so, but the unexpected onset of hyperventilation and the inability to control breathing can bring on feelings of panic which, in turn, can prolong the hyperventilation. Prolonged episodes of hyperventilation can also result in fainting, which would obviously lead to drowning. Even if fainting doesn’t occur, people who panic are more likely to experience swim failure and drowning.
Once the hyperventilation stage ends, the swimmer should have at least a short time to perform necessary rescue skills before incapacitation brought on by exposure to the cold water makes it difficult to use one’s hands and feet. In very cold water, you may only have 10-15 minutes before this happens. However, the significant lowering of the body’s core temperature, or hypothermia, will likely take 30 minutes or more to cause the death of a capsized paddler.
The good news is that by wearing appropriate immersion clothing like a wetsuit or drysuit to protect a paddler from the water temperature, paddlers can prevent the dangerous effects of the cold water gasp reflex and greatly extend the time before cold incapacitation and hypothermia will set in. At a bare minimum, wearing a life jacket (PFD) can potentially save your life by keeping your head above water for the duration of the cold shock response. A paddler wearing a life jacket may still swallow some water if the gasp reflex occurs while the person’s head is underwater, but there is at least the possibility of rescue if the capsized paddler remains at the surface due to the buoyancy of his/her life jacket.