What is Cold Water Shock?

What Happens During Cold Water Shock?

Sudden immersion in cold water can trigger an involuntary gasp reflex, rapid breathing, increased heart rate and temporary loss of breathing control. This can happen extremely quickly and may make it difficult to stay calm or swim effectively.

Even relatively mild outdoor water temperatures can trigger cold water shock, especially if the body is unprepared.

Why It Can Be Dangerous

Panic, disorientation and breathing difficulty can all increase the risk of drowning. Cold water may also reduce muscle control and swimming ability surprisingly quickly.

Jumping unexpectedly into very cold water can make the initial shock response significantly worse.

Reducing the Risk

Gradually entering the water, understanding conditions beforehand and wearing suitable thermal protection such as a wetsuit may help reduce the intensity of cold water shock.

Taking time to acclimatise, avoiding alcohol and never swimming alone are also important safety considerations.

Safety Swimmers and Spotters

Having confident swimmers, spotters or safety swimmers nearby can be extremely valuable in cold-water environments. If somebody becomes overwhelmed or struggles after entering the water, rapid assistance may be critical.

At more serious jumps or colder locations, some groups choose to have designated safety swimmers already in the water before jumps take place.

Know When to Walk Away

If the water feels dangerously cold, conditions look poor or confidence is low, the safest option may simply be not to jump. Outdoor conditions can change rapidly and there is never any shame in deciding not to continue.