Cold Water Shock
Published: 02 July 2026
There are sadly several stories of people rushing into rivers and streams and getting into difficulties. 47% of UK accidental drownings occur between May and August, when we are most at risk of cold water shock which has three stages:
1. a similar sensation to getting into a swimming pool, characterised by a gasp for breath, then followed by rapid breathing (hyperventilation).
2. as your breathing goes out of control, your blood pressure shoots up as your body tries to keep your blood warm by moving it towards the middle of your body (this is why you go pale when you’re cold).
3. as your muscles cool, your strength, endurance and muscle control reduce to the point when you can’t swim any longer, so you can’t rescue yourself. The point at which you can’t swim any more is called ‘swim failure’, and if you haven’t got out of the water or managed to get hold of a buoyancy aid (like a lifejacket) by this time, you will drown.
Safety advice says don’t jump straight into unknown water but enter gradually, wearing protective and visible gear if possible. If you get into difficulties, don’t thrash around but float on the surface until your breathing recovers, and call for help. If you see someone in difficulties, don’t jump in yourself but throw them something that floats - best of all, never go wild swimming on your own.