guide

Cold water shock explained

What can happen when someone enters cold water suddenly and how RNLI guidance says to respond.

Sudden immersion in cold water can trigger an involuntary gasp and rapid, difficult-to-control breathing. This response can make it harder to keep your airway clear and can impair movement. The RNLI describes water at 15°C and below as cold enough to seriously affect breathing and movement.

Reduce the sudden shock

Check conditions before entering and get in slowly rather than jumping or diving. Stay where you can manage the conditions and keep an exit in mind. Wearing a wetsuit does not remove cold-water risk.

If you fall in

Try to stay calm and float on your back until you can control your breathing, following Float to Live. Then call for help or move to safety if you can. In a coastal emergency call 999 or 112 and ask for the Coastguard.

Cold exposure affects people differently; this explanation is not a personal risk assessment.