The benefits of swimming in cold water – by Calum Maclean

October 02, 2024 13 min read

The benefits of swimming in cold water – by Calum Maclean

‘You never regret a swim.’

This is a philosophy to try and live by when it comes to swimming outdoors. I say try to live by, as when there’s an icy wind, grey skies and dark water in the thick of winter, it can be very easy to ask, why am I doing this? The big ‘WHY?’ is a question that gets asked by family, friends, puzzled onlookers and even curious animals. At times, the truth of ‘why’ does not come during the swim, but in the aftermath: in shared tales of water with friends; in the look across the sea to a distant island; in the glow of heat returning to once-frozen toes; in the realisation of, wow, I just did that; in the sheer buzz that zips around your body after leaving the water and comes flying out of your mouth in a howl.

At times, it can feel like type II fun. Having said that, it doesn’t need to be a struggle. We can find the joy and truth within the activity: the feeling of gliding through calm water, the zen-like state reached after hours of left, right, breathe, left, right, breathe, the power of controlling our breath and getting over that initial shock upon entry. There’s also the learning of new and exotic ways to swear and entertain the wise, towel-holding friends.

All swimmers enjoy it for their own reasons: some want the challenge and focus of long-distance swims, others just enjoy being in the cold. 1001 Outdoor Swimming Tips looks at all the types and aspects of swimming, with a focus on what I know.

 

COLD WATER

  1. I don’t bother with a thermometer (usually). Instead, I have my own tried and tested ‘Scottish water temperature chart’, which you can apply to your swim. Here’s how it works:

Roasting

On a beautiful summer’s day (you get this a couple of times a year in Britain), when the sun’s been on the water all day, it’s like being in a bath. You could be in there for hours – it is beautiful. That’s roasting.

Decent

This happens during summer, maybe on a nice summer’s day or at the end of autumn: you see a good stretch of water, the sun’s been on it and you can get in there and swim without a wetsuit. That’s decent.

No bad

This is when you get in and you don’t want to get back out immediately. It’s basically if the water doesn’t cause your feet pain. Oh, that’s no bad like.

Aye, alright

Aye, alright happens when you get in the water and after you paddle about for a bit your mates on the side ask, ‘What’s it like?’ Shivering with the cold, you say, ‘Aye it’s alright!’ ‘Aye ... alright,’ comes the suspicious reply from the shore.

A wee bit chilly

Sometimes it’s a wee bit chilly. This is when it’s pretty sore to get in without a wetsuit on. You duck your head under, you paddle about a bit, you come up you get that horrible cold head (also known as ice cream head) – that is starting to get a bit brutal.

Cold

This is pretty self-explanatory. For me, it’s when I get in the water and things are starting to get a wee bit smaller – I’m obviously talking about my hands here, which get really shrunken and shrivelled in cold water. Only my hands, though – nothing else!

Baltic

This is basically when you’re breaking the ice on the edge of the water to get in. It’s kind of like the hokey-cokey: you get in, out and shake it all about, and make sure everything is still intact on your body. It’s brutal. Baltic can also be referred to as, ‘hoora cold’ and ‘forget this, I’m getting out now.

 

393. You will never feel more alive and invigorated than after a swim or immersion in cold water.

394. At what temperature is water ‘cold’? If we go by Fédération Internationale de Natation (FINA) competition guidance, it may come in at anything below 20 °C – this is the temperature up to which you may be allowed to wear wetsuits in a competition. To me, 20 °C is borderline ‘roasting’; some people might consider anything under 18 °C to be cold. A common definition of cold water is 15 °C and below, while others may say 10 °C. In summary: one person’s cold might be another person’s cool, so judge for yourself whether you think the water is cold rather than relying on other people’s input.

395. Once you get below 10 °C or so, even a change of 1 °C can feel much more stark than at higher temperatures.

396. Forget any glamorous pictures: the reality of cold water is that it’s hard work.

397. When we enter cold water, our body wants to protect itself: to keep the core warm, blood flow to extremities and the skin slows down (peripheral vasoconstriction). This is why your skin will feel cold when you get out. As blood flows back to your extremities after a swim, you’ll feel powerful and more alive than ever. This is the euphoria that keeps people coming back.

398. Despite my supposed aversion to actual thermometers, they can be very useful: gathering data of how the water feels at different temperatures and when your comfort levels change can help you understand how your body deals with the cold. However, I wouldn’t recommend using a thermometer reading as a hard and fast rule on how long you should swim for.

399. If you’re going to measure water temperature, do it at multiple places: the shallow edge of a lake could be a lot warmer than out in the depths, but also the shallow water might be colder as it freezes more quickly. As water is a dynamic environment, with many factors affecting it, you can also find warmer patches, mainly at surface level.

400. Getting used to swimming in the cold takes time: months, even years.

401. The best time to start cold-water swimming is when the water is warm. By starting in summer and continuing to swim as temperatures drop, your body can adapt to the gradual change. As the famous quote says, ‘Just keep swimming!’

402. The change of water temperatures is not always a constant, gradual change: depending on your location, the water temperature may alter significantly in a matter of days.

403. Stay dressed until you are ready to swim.

404. Swim faster to produce heat: the more you move, the more heat you make.

405. Get bigger to help deal with the cold. A larger body mass helps deal with cold, effectively by creating insulation on your body. Both muscle and fat help: muscles produce heat as they get used, and larger muscles produce more heat but also require more energy; body fat provides a layer of insulation, slowing down the cooling process as you lose body heat to the water. Think of the denizens of the ocean, such as seals – they are very strong, but with a larger layer of fat (blubber) over their muscles.

406. Know what cold water shock is. When you enter cold water, your skin starts to cool. This triggers a response in your body that makes your heart rate rise, and you may gasp for air and start to panic. This can cause a heart attack and lead to drowning. Typically, cold water shock will last just a few minutes, and the more you expose your body to the cold water the more adaptation takes place and your body’s shock response reduces.

407. If you find yourself unexpectedly in cold water or suffering from cold water shock, follow the RNLI’s guidance of Float to Live – lie on your back, lift your legs up and stay calm.

408. Not all cold water acclimatisation is the same. By this I mean that being comfortable in 15 °C water does not mean that you will be comfortable in 10 °C water – cold water shock may return.

409. In any cold water, getting in can be the hardest bit, both physically and mentally. It’s always best to ease yourself in by wading in, allowing your body to realise what is happening.

410. Don’t get into the water if you’re already cold. Always get warmed up and comfortable before entering the water. A good way to get warmed up for me is to perform air squats, and even press-ups, while fully dressed. Each will get your blood flowing around the body.

411. Psychology is big part of getting into cold water. Even when you have done it hundreds of times, just the thought of forcing yourself into the cold can be daunting. I have a variety of ways to handle this, but here’s some of the things I currently do to psych myself up:

  • I talk to myself, sometimes quietly but mostly loudly.
  • I take on the persona of a fervent religious leader, and make wild and bold assertions.
  • I will be ready to fight, like a boxer entering the arena of battle. With my robe on, I am Muhammad Ali making the ring-walk. I am a gladiator. My battle, however, is not with the water: it is with myself. As I put my hat and goggles on, it is like putting on my final pieces of armour. As I enter the water, I go into the arena of war. I am ready.

412. Don’t fight the water; see yourself as being part of it. As you enter the body of water, remember that your body is mostly water, and know that you are entering into a very natural activity.

413. Even once you have adapted to the cold, take the first 90 seconds of a swim to get used to the water. Don’t immediately swim or even stray into deep water if you don’t have to. Let your body feel the cold around you and focus on your breathing, especially keeping it under control. This is also a good way of gauging how your body initially feels without the distraction of swimming. After the first minute you should start to feel relaxed and your focus can start to switch to the actual swimming.

414. Keep your head warm. Some people like to dunk their head in almost immediately, but I have never been a fan of this as it instantly cools you down further and will cut short what time you can stay in the water. However, if you are well wrapped up in a swim cap and will be swimming with your head in the water, go for it.

415. If you don’t intend on getting your head wet during a swim, then wearing a warm hat like a woolly or bobble hat is a great solution to keeping your head warm. Being able to keep one hat on throughout the entire changing, swimming and recovery process helps preserve your energy. Carry a spare hat for after the swim, just in case it does end up in the water.

416. Your extremities (hands, feet and head) will suffer the most in cold water, and this is what can cause the most discomfort during and after a swim. Protect them with neoprene to allow yourself to swim for longer and recover more quickly.

417. If you start to shiver in the water, get out. You should be out of the water well before you begin to shiver. Shivering is the natural process of your body trying to warm itself up by involuntary muscle movement. It is energy intensive and will often occur as part of the recovery from a cold swim, but this should happen after exiting the water when you are wrapped up warm. In the water, heat from the body is rapidly lost to the environment and shivering is a sign that your body is currently too cold.

418. Learn about your body over time. I cannot tell you exactly how your body will react to the cold, and how easy your recovery process will be. A particularly hard recovery or cold swim may initially frighten you or even others around you, especially if uncontrollable shivering kicks in. Shivering is good in that it helps your body warm up, however uncontrollable shivers may be a sign of hypothermia. The trick is really to keep at it over time: keep on learning over many cold swims, which will help establish an under-standing of your body and how it reacts.

419. Kick or swim harder to produce more heat, but remember you will also tire more quickly.

420. Swearing out loud a lot helps. It just does. Make them creative, don’t just stick with the boring effing and jeffing. A solid 10–15 swears when getting into the water translates to a good 10–15 minute swim. That’s solid science.

*421. Hollering, shrieking and heavy breathing can be used instead of swearing.

422. Swimming in cold water in a wetsuit can be easier on the body than without, but it’s still not easy.

423. You, the swimmer, might not be the best judge of how you are doing. Listen to your safety team and helpers. Use people you trust, and work with them overtime so that they get to know you.

424. If you start to feel euphoric and warm, it’s time to get out. The feeling of euphoria is pretty common after a swim and is part of the natural high that keeps people coming back to cold water. However, it will often occur just before the recovery process, so anticipate this by getting rewarmed rather than standing around feeling like a superhuman.

425. Respect THE CLAW! If your pinky finger goes walkabout and you cannot close it beside the rest of your fingers, it could be time to get out: as your arm nerves cool, muscles contract and your fingers spread until eventually your hand cannot be closed. This finger spreading also hampers swimming technique.

426. Ignore the opinion of those people who don’t know about cold water and don’t know you personally. Listen to those who either understand the cold or care about and understand you– give special time to the ones who understand both.

427. For your first cold swim, try swimming with a wetsuit on. At the end of your swim, if you are feeling good and not suffering, then strip the wetsuit off and swim in your costume only. You’ll get an idea of how your body handles each option and what you prefer.

428. It may take multiple swims for you to understand if you prefer swimming skins or with a wetsuit; it might bean epiphany that comes immediately.

429. Hunger, thirst, being hungover and poor sleep are all factors that will make you feel colder, or feel cold more quickly.

430. Cold water just might not be for you. You can’t have missed the reams of articles on the sheer joy and exhilaration of cold-water immersion, but not everyone will enjoy it: some bodies suffer more than others.

 

ICE SWIMMING

431. Ice swimming is a very extreme activity – remember that before trying.

432. Never ice swim alone.

433. The categorisation of ‘ice swimming’ is often accepted as swimming in water that measures 5 °C or below.

434. There doesn’t have to be ice on the water for it to be classed as ice swimming.

435. You will swim slower in ice water.

436. Have low expectations of yourself initially. Some swimmers count the strokes, not the minutes.

437. Go for your first ice swim with experienced swimmers who have done it before. Treat your first few swims as immersions, to feel the cold, rather than actual swims.

438. Don’t just ‘give it a go’. Plan every ice swim fully, no matter what distance or time. Always remember to factor in your recovery.

439. Fresh water cools down much faster than the sea during the year, and will reach colder temperatures. It’s rare for seawater to reach 5 °C, unless you are very far north or south on the planet, where the sea can reach a temperature of approximately -1.8 °C before freezing, as salt water has a lower freezing point.

440. Bodies of fresh water, especially shallower water, are susceptible to environmental and weather-related factors which can lead to dramatic changes in temperature over a period of even a few hours. For this reason, the thickness of ice may change or entirely disappear from a lake or pond. What is classed one day as an ‘ice swim’ may simply be ‘a swim’ by the next morning.

441. The ‘one minute in the water per degree Celsius of temperature’ rule of thumb used by some swimmers is not wise for all: this is far too vague and does not take into account the myriad of other factors at play in cold water. Just because someone else does it, doesn’t mean you should do it too.

442. Don’t ice swim multiple times in a day; even going into icy water every single day can become a real toll on the body. If cold-water immersion, rather than swimming, is your aim, even a period of two minutes can get you the buzz you need.

443. The ultimate goal for some ice swimmers is an ‘ice mile’. It is what it sounds like. It’s not for everyone.

444. In order to complete an ice mile or a distance swim ratified by one of the organising bodies, the swim must be undertaken in a standard swimming costume, goggles and one swim hat.

445. An ice mile is something that has to be built up to over several seasons of regular swimming and conditioning. You should be swimming all year round, getting used to the way the water temperature changes with the seasons. Getting into the water regularly is crucial – several times a week is recommended. If you aren’t able to swim several times a week, cold-water immersion and even cold showers can be used to help replicate the cold. You may need to try and source an old open-top freezer to sit in ... !

446. For safety purposes, most ice miles now take place within a standing body of water and require the swimmer to complete laps, rather than one long-distance, point-to-point swim.

447. If you’re actually going to break ice, use blunt force on it. An ice axe that people use for winter walking or climbing is designed to grab or hold ice, so use a hammer or sledgehammer. An axe can be used if you have experience of using one.

448. Ice sprays everywhere when struck. Protect your eyes and know that whatever you’re wearing could get wet.

449. Stay warm while you make a channel in the ice. If it involves wading, consider wearing a wetsuit or even a drysuit while making it.

450. Ice is sharp; skin is soft. Thick ice can cut you, so use gloves to move slabs around. Once you break ice, use something to clear it away from the channel or hole, such as a lightweight snow shovel.

451. Sharp ice can also cut swimming-specific wetsuits.

452. To make an ice hole in thicker ice, you can use a sledgehammer, ice-drill, ice saw or a large axe. By cutting a square, you create a small floating island of ice – this can either be lifted out from the hole or pushed down and along, so that it slides away and will sit under the ice, away from your hole.

453. Ice thickness can change overnight. Make a new assessment each time.

454. Don’t walk on ice unless you are sure it’s thick enough. Stay close to the sides of the body of water.

455. Never walk over ice on deep water, unless you are absolutely sure of its integrity. As I watched Finns skip straight across a shortcut of the frozen Töölö Bay in Helsinki, I was quite happy to take the longer walk around it.

456. Snorkelling in ice-cold water is a grim experience, and dangerous. I do not recommend it.