How long should you stay in cold water swimming?

You may think that swimming in cold water is one of the last things you'd dream of doing, but there's significant health benefits attached to it. IPRS Health clinician Hazel Rudder writes about her cold water swimming experience and why you should take the plunge.

On a cold December night, I took off my coat and stood in my swimming costume on the slipway of a secluded harbour. There was a full moon, but it was blocked by clouds whirling past in the stormy sky. The masts of boats rattled in the wind as the freezing waters lapped around their hulls. No turning back …this was it… a December moonlight cold water swim – the Polar Bear Swim.

This would be seen by most as the start of a very dark story – and to me a few months before, it would have seemed like madness. In truth, the harbour was lit by fairy lights, lifeguards shuddered in full dry suits on their paddleboards on the perimeters of the swim course, and glow sticks were handed to swimmers as they entered the dark waters, which were handed back and counted as we exited the water. There was a band playing, and warm soup was handed to swimmers on completion of the swim, along with a Polar Bear badge. The swim was in aid of a local cancer charity and the support, comradery and… yes – I’ll say it… “fun” was something unprecedented!

Cold water swimming is gaining in popularity and momentum as it sweeps the UK as a pastime, accessible by pretty much everyone over the age 16. Studies have been completed looking into the health benefits, and TV shows such as Countryfile are dedicating their airtime extolling the virtues of swimming outside, all year round. As a hardened surfer, I had never imagined that going into the sea a few times a week, with a bunch of people that I would never have crossed paths with – without a wetsuit – would be such fun, and so addictive. I have grown to love this crazy pastime and cannot imagine life without it now.

Benefits

Believe it or not there are some great benefits to performing cold water swimming! Here is a brief summary:

1. It boosts your immune system

The effects of cold water on the immune system have been studied widely. Cold water helps to boost the white blood cell count because the body is forced to react to changing conditions. Over time, your body becomes better at activating its defences.

2. It gives you a natural high

Cold water swimming activates endorphins. This chemical is what the brain produces to make us feel good during activities. Cold water swimming is also a form of exercise, and exercise has been proven to treat depression. Cold water swimming brings us close to the pain barrier. Endorphins are released when we’re in pain, to help us cope with it.

3. It improves your circulation

Cold water swimming flushes your veins, arteries, and capillaries. It forces blood to the surface and helps to warm our extremities. Repeated exposure adapts us to the cold.

4. It increases your libido

Cold water was traditionally seen to repress sexual urges. The fact is that it increases libido! A dip in some cold water boosts oestrogen and testosterone production, adding an edge to fertility and libido.

The benefits of increased libido include more confidence, higher self-esteem, and enhanced mood.

5. It burns calories

The heart has to pump faster in cold water and the body must work harder to keep everything warm while swimming. Overall, far more calories are burned during cold water swimming than swimming in warmer conditions. The idea that drinking cold water increases the number of calories you burn may be a myth, but it is a fact that cold water decreases your body temperature so much that the body must act.

6. It reduces stress

Cold water swimming places stress on the body physically and mentally. Many studies have identified the link between cold water and stress reduction. Cold water swimmers become calmer and more relaxed.

7. It is a great way of socialising and making new friends

There is a great sense of community and camaraderie amongst cold water swimmers. There is nothing that brings people together like facing a challenge and sharing the experience as a group.

There are ongoing studies into the effects of cold-water swimming and the menopause. The difficulty is that it is difficult to prove that it is specifically the cold water that is having the positive effect – as the aspects of socialising and doing exercise will both improve general health and wellbeing. What’s not to like?

Safety

Of course, there are safety considerations for any sport. One that involves immersing yourself in freezing cold water without a wetsuit probably warrants a bit more focus on the safety… there are rules – these are taken from the Outdoor Swimming Society website, where there are lots of useful  resources.

1. Acclimatise

As the temperature drops, just keep swimming and your body will get used to the cold. This time of year is the perfect time to start cold water swimming. It will not be such a shock to go through the year then, as the sea temperature starts to fall.

2. Be safe

Open water can be dangerous. Only ever swim where it is safe, and make sure you can enter and exit the water quickly and easily.  Never swim on your own.

3. Wear the right kit

Wear a swimming hat, or two, to help preserve body heat (we often wear woolly hats or earmuffs).  You can also wear neoprene gloves, booties, balaclava or a wetsuit – whatever you feel comfortable with (although you may be ribbed by the group if you wear a wetsuit!)

4. No diving

Do not dive or jump in unless you are used to the cold water.  Cold water can cause gasping of breath and cold-water shock, which can be extremely dangerous.

5. Know your limits

As the temperature drops, decrease the amount of time you spend in the water. In winter, swimmers often only swim for one or two minutes at a time. The general rule is that you can spend 1 minute per degree of water temperature in the water – obviously, you need to listen to your body too.

6. Warm up slowly

Don’t have a hot shower. Hot water can cool your core and it can be dangerous. Instead, make sure you have plenty of warm clothes, wrap up well and have a hot drink.

And finally, spend the rest of the day on a high, trying to convince your friends and family that you’re not completely nuts.

So, those are the benefits and challenges of cold-water swimming in a nutshell. There are lots of groups all over the UK swimming all year round and there is a really great sense of community where everyone is welcome to join in on local swims. Have a look and see what is local to you. You don’t need to be a fitness guru – or in swimsuit model shape - just open minded, up for a challenge, and game for a laugh. This may be the favourite hobby you never knew you had!

Further information:

http://www.wildswimming.co.uk

https://wildswim.com/

https://www.bbc.co.uk/news/uk-wales-47159652

Image Credit:

Swimmer - Claire Wilson

Location - Devon Island, Canadian High Arctic

Copyright - Andrew Wilson

With the growth in outdoor swimming during the pandemic, and with more people trying it out this winter, the question of whether the body gets used to cold temperatures if you swim often is much debated.

The short answer is “it can”. But it’s a bit more complicated than that. Your body can acclimatise to cold if you repeatedly swim outside, but whether or not this is a good thing depends on what happens to the body’s adverse responses.

What happens to your body?

There are three potentially hazardous physiological responses associated with going into cold water. The first is the cold shock response (CSR), this is the uncontrollable gasping, breathing and increase in heart rate that occurs for about 90 seconds when you first go in. The second is cooling of the nerves and muscles close to the surface of the body, particularly in the arms and legs that, when cooled enough, incapacitate you and stop you exercising . The third is hypothermia as deep body temperature falls below 35°C, this normally takes at least 30 minutes to happen in an adult in cold water.

Each of these responses varies in the amount it “acclimatises” with repeated exposure to cold water. But as few as six, three-minute immersions in cold water can reduce your cold shock response by 50%. This reduction in the response to a repeated constant stimulus is called “habituation”.

Both children and adults can become used to the CSR and this habituation can still be reduced seven months after being established. Habituation makes swimmers feel more comfortable getting in to cold water, so it becomes easier to take the plunge.

If you immerse one side of the body repeatedly in cold water, the habituation you develop remains if the other side of the body is immersed in cold water. This tells us that this habituation is happening somewhere more central in the body than at the skin cold receptors. Even having cold showers can help people get used to cold water, but showers are not as effective because they don’t cool the skin as much or as quickly.

Read more: Swimming gives your brain a boost – but scientists don't know yet why it's better than other aerobic activities

Interestingly, the ability to suppress the CSR and hold your breath on initial immersion can be improved without going into cold water.

If the body doesn’t get used to the chilly temperatures drowning and heart problems can happen on initial immersion. So, the habituation of the CSR is important if you want to swim in cold water. It is best to stay still for a couple of minutes when first going into cold water to reduce the risk of taking water into the lungs.

Even people who swim regularly in cold water run the risk of becoming physically incapacitated if they overstay their welcome. This problem can start after just 10 minutes of swimming in very cold water and, because people who swim outside regularly feel more comfortable in cold water, the incapacitation can come as a bit of a surprise. The only useful defence against this response is increased insulation (body fat or wet suit).

Shivering less

People may shiver less with repeated dips in cold water. Swimmers can feel more comfortable in cold water as a result, but cool more quickly. One of the first studies to show this was undertaken by the physiologist Griff Pugh (the scientist who also helped Hilary and Tenzing get to the summit of Everest), and Otto Edholm.

They studied the best open water swimmer of his time (1950s), Jason Zirganos, and demonstrated hypothermic adaptation when he was sitting still in cold water. When swimming, Zirganos stayed warm because of the heat he was producing by swimming, and the fact that he had a significant amount of body fat. Unfortunately, his acclimation had also reduced his ability to sense cold. This led to his death in 1954 whilst trying to swim the Irish sea; he died from hypothermia having never felt particularly cold.

Finally, some believe that those who are acclimatised to cold develop more “brown fat”, a special type of body fat that can produce heat. But the small amount of such fat is unlikely to make up for the reduction in heat production caused by the habituation of shivering.

So, yes, your body can get used to cold if you swim in cold water regularly. A reduction in the cold shock response and associated risks is a good thing. Importantly, however, you can still become physically incapacitated in a short time in cold water. Finally, once you have become adapted, no matter how comfortable you may feel, this doesn’t necessarily reflect how cold you are.