Swim your own swim

Cold water requires a new mindset. It's about survival, not time or distance. That means forgetting goals, learning to read your body and swimming your own swim.

The huge mental health benefits of cold water swimming come from putting your body into survival mode. You're training your physiological reaction to stress, behaving mindfully and reducing inflammation just by getting in cold water and then getting out again. Two minutes is all it takes. Don't forget that.

Yet, so many people are pushing the boundaries. Not just endurance challenge swimmers, but everyday cold water dippers. It was bound to happen as cold water became popularised. But coaches, lifeguards and experienced swimmers across the UK are getting more and more worried that somebody will soon pay the ultimate price for their new hobby.

What can go wrong?

An experienced swimmer who was well-acclimatised over a few years tried to swim 1km in the sea at 7C. As she got colder, she started to lose cognitive function. It's an early stage of hypothermia and it makes the swimmer unable to make decisions for themselves. We could see that she was caught in a current and she wasn't going to make it to her destination point. But, instead of swimming to the beach and getting out, she kept trying. Her stroke was slowing and from time to time she stopped completely. When the RNLI pulled her out, she was barely conscious. She was taken to hospital, where she had the lowest blood pressure medics had ever taken on someone who survived, and her heart was in arrhythmia.

Another experienced swimmer stayed in 6C for 20 minutes and also ended up in hospital with hypothermia. Another had a heart attack after diving in. Another suffered circum-rescue collapse after staying in 5-degree water for 9 minutes... Cold water swimming is very dangerous. Cold water shock, swim failure and hypothermia are all very real risks.

How you can protect yourself

That doesn't mean don't do it, just take extra precautions. The best way to do this is to treat it like a form of therapy or an experience rather than exercise. It's such a different beast from summer swimming, and that requires a change of mindset.

Don't copy others

One of the biggest mistakes people make is watching others and copying. On social media and at swim spots, you'll find people demonstrating or (and this is unforgivably dangerous) bragging about how long they stay in the water at certain temperatures. IGNORE THEM. They are not you and there are no benefits at all for staying in for longer than a couple of minutes. They may be staying in longer because:

• They are attempting a hard-core endurance challenge such as an ice mile, and are doing structured, disciplined training.

• They don't mind having a rough, higher-risk recovery and part of their training is dealing with that.

• They have been cold water swimming for a few years - acclimatisation builds up over years as does understanding one's own physiological reaction to cold water immersion.

• They are better insulated and adapted to cold water than you.

• Or, they're ignorant or reckless.

Dips not distance

This is the phrase I use the most when coaching winter swimming: 'it's time to get out now'. It's tempting to think that because you've taken the morning off and driven for half an hour, you should swim as long as possible. This is completely wrong. Instead, develop a lovely ritual around your dip, this might include:

• Laying out all your stuff in order before you get in

• Wrapping your clothes around your hot water bottle

• Dipping briefly

• Dressing quickly in warm layers

• Tucking your hot water bottle up your top

• Drinking and eating something nice and warming

• Chatting and laughing with friends

If you view this whole process as an experience, you will enjoy your swim more.

Risk assess every swim

This sounds a bit anal, and I don't write down a full risk assessment. But before you get into the water, you need to assess the dip ahead of you and yourself. This means thinking about:

• The weather - the air temperature and wind chill will affect how you cope with the cold that day.

• The water - is it choppy, are there currents? Think about where you'll get out bearing in mind that you'll be physically tired and less able to manoeuvre yourself when you're cold.

• How you're feeling - if you've had a poor night's sleep, you're coming down with something or recovering from illness, you'll find it harder to acclimatise.

• When you last swam - if you've had a long gap or been on holiday to a warm country, this will affect how you deal with the cold.

• Whether you ate breakfast - being hungry or dehydrated can also affect how you cope with the cold.

• Whether you drank alcohol the night before - being hungover will seriously compromise your ability to warm up.

Forget the 'one-minute' rule

In fact, forget your watch completely. You should not be timing your swim, and you definitely should not be aiming for a certain time or distance in the water. Instead, learn how to read your body. Pay attention to the different sensations you feel and get out while you're still comfortable.

Five minutes at five degrees centigrade may not sound like much, and some people will be able to stay in for this long without any problems at all. But others will struggle to recover from this same swim. Equally, just because you could do this swim a couple of days ago does not mean you can do it today. If you're unsure, make your dip shorter.

Staying in the water for too long is probably the most common mistake that people make. Parliament Hill Lido in London recently reported that they were dealing with a casualty a day because people are trying to stay in the water for too long. But they have trained lifeguards on duty. If you swim somewhere without a lifeguard, you could be in serious trouble.

The bottom line is this: the cold water fix, buzz, benefits - whatever you call it - comes from being in the water for just a couple of minutes. After that, you're just increasing your risks of being the next casualty. Please swim safely.

*I cap all coached sessions at 1 min per degree because I'm not in the water. However, I coach all my swimmers to learn how to use their own judgement and I often decide you should stay in for less time than this using my own assessment of your state and the conditions that day.