Cold Water Shock: What It Is and How to Avoid It

If you take one thing away from this article, let it be this: cold water shock is one of the biggest risks in wild swimming, especially if you're new to it.

It doesn't matter if you're a strong swimmer in the pool, cold water doesn't care. It's what happens to your body in the first minutes after you get in that catches people out.

The good news is that cold water shock is well understood and, in most cases, it's avoidable.

What is cold water shock?

When your body suddenly enters cold water, usually below around 15°C, it reacts instantly.

You gasp, your breathing becomes fast and difficult to control, your heart rate increases and your blood vessels constrict. If your face is underwater when that involuntary gasp happens, you can inhale water before you've had a chance to react.

Cold water shock is a significant factor in many accidental drownings in UK waters, which is why it's so important to understand how to reduce the risk.

One thing that surprises a lot of people is that this can happen in the middle of summer. A warm sunny day doesn't mean warm water. Lochs, rivers and the sea take much longer to heat up than the air, so even during a heatwave the water can still be cold enough to trigger cold water shock.

How to reduce the risk of cold water shock

Walk into the water slowly rather than jumping or diving. Give your body a minute or so to adjust before you start swimming.

Focus on your breathing. Slow, steady breaths will help you regain control much more quickly than fighting against the sensation.

If you're new to wild swimming, build up gradually over the season. Your body adapts over weeks and months, not during a single swim.

Keep your first swims short. Five to ten minutes is plenty while you learn how your body responds to different temperatures.

Swim parallel to the shore rather than heading straight out. If you need to get out quickly, you're never far from an exit point.

Always swim with other people if you can. Wild swimming has an incredible community and it's always safer when someone knows where you are.

If you get into trouble

Even experienced swimmers can be caught out.

The RNLI's advice is simple: Float to Live.

If you find yourself struggling, fight your instinct to swim hard. Instead, lean back, float on your back with your ears submerged, spread your arms and legs and concentrate on controlling your breathing. Once the effects of cold water shock have settled, call for help if you need it or swim to safety if you're able.

If you haven't already, spend five minutes reading the RNLI's Float to Live advice: https://rnli.org/water-safety/float. It's simple, easy to remember and could save your life.

Getting out safely

Getting out of the water isn't the end of the story.

Your body can continue cooling after you've left the water, something known as afterdrop. That's why getting changed and warming up quickly is just as important as getting in safely.

Have warm, dry layers ready. Get out of your wet swim kit as soon as you can, put on a hat, add plenty of layers and shelter from the wind if possible.

That's exactly why we created Wild Changer, to make getting changed outdoors quicker, warmer and a lot less faff, leaving you to enjoy the best part of any swim, a hot drink and a chat with your pals.

The bottom line

Wild swimming is one of the best things I've ever done, but it deserves respect.

Check the water temperature, take your time getting in, control your breathing, swim with others and know the RNLI's Float to Live advice before you ever need it.

Do those simple things and you'll stack the odds firmly in your favour, leaving you free to enjoy everything that makes wild swimming so special.