Acclimatising to open water (or cold water, depending on how you view it)

The OSS pledge to 'embrace the rejuvenating effects of cold water' is a valuable mindset change for any open water swimmer. At first it may seem inconvenient that British waters are not warmer, but you may soon find you're addicted to the fresh feeling of natural water.

The good news is that it's relatively easy to acclimatise yourself to water temperatures in the UK, by nothing more complicated than swimming regularly in them.

The human body acclimatises to cold water so well that hundreds of swimmers cross the channel every year (at around 16 degrees, for 10 hours or more, any untrained swimmer would get hypothermia), and a few swimmers have even trained themselves to swim in the Artic.

Getting yourself into a situation where you enjoy summer swimming, particularly if you're prepared to start out with a wetsuit, should not take long.

TIPS ON IMMERSION 

  1. TAKE THE PLUNGE! Much of the acclimatisation process is mental - knowing the moment of immersion will feel cold, and embracing it anyway.
  2. EXHALE AS YOU JUMP IN. In cold water the ribcage contracts, which leads many swimmers to feeling they can't breath. Exhale and the next breath will come naturally in. Shrieking, grunting and fwaw-fwaw-fwawing for your first strokes are perfectly natural accompaniments to a wild swim.
  3. WAIT 90 SECONDS. The pleasure of open water might not be immediate. Give your body a little time to react, and soon your circulation will start charging around and you'll feel alive. Swimming outdoors is medically proven to be good for circulation.
  4. FIND A ROCK OR TREE TO SWIM TO. Don't just jump in and think about how it feels, as the answer is likely to be 'cold', even unpleasant (particularly in wetsuits, where the expectation of warmth makes the cold dribble in around the zip particularly cruel). Set your intention (to swim to x), and then get in and do it. You'll feel good once you get moving.

COLD WATER IMPAIRMENT 

The main safety risk you face as a wild swimmer is getting too cold. 

You get in , and after a few minutes of feeling uncomfortable the water feels pleasant. As a novice swimmer, you then attempt to cross the lake, but half way across start feeling cold again.  Your body continues to lose heat, blood shunts to the core to keep organs warm, muscles slow, arms and legs become weak, and swimming becomes increasingly difficult. i.e. you are "in difficulties" and sadly may soon drown.

The media often report water related deaths as if they are mysterious, as if we can't predict what will happen when we're in it, and therefore we should just stay out. This isn't true. We know how cold impairs swimming, and we can moderate our risk by

  1. Wear a wetsuit, silicon hat, maybe even booties and gloves depending on the time of year (see our wetsuit Q&A)
  2. Swim close to the shore
  3. Acclimatising

 In truth, there are very few swimming deaths. More commonly there are water-related deaths, for example people are drunk and get into water (the issue here is the alcohol, not the water, it also leads to problems if driving, hang-gliding, etc), victim to an accident (eg fall off a boat, walk off a ledge, not setting out to swim or necessarily able to swim), get swept into a river or lake (eg in a storm,  in winter, fully clothed, when not setting out to swim). These events are all tragic but do not have lessons for the open water swimmer, who wants to reduce their own risks.

Rob Fryer from the River and Lakes Swimming Association referred us to research carried out by Portsmouth University and the Swedish National Defence Research Establishment, published in the Lancet in 1999, confirms that drownings associated with cold water are usually caused by swimming impairment.

OTHER RISKS OF COLD WATER

Other risks of jumping into cold water include

  • Cold shock
  • Hypothermia
  • Cramp
  • Heart attack
  • Asthma
  • Cold water urticaria

 These are all real risks, and anyone with a heart condition and asthma has good reason not to attempt winter swimming at all, and talk to their doctor before swimming in warmer (but still chilly) summer UK waters.

However, thousands of people swim outdoors safetly every year, and even more survive festive dips - one off jumps into the water - with mountainous goosebumps to show for it.

For those who get hooked on wild swimming, we find it takes about 3 years for OSS members to go from thinking all water is chilly, even in summer, to wanting to swim in winter, just for the experience. (Come to our annual OSS December Dip, the first Saturday of December, if you want a thrill). 

COLD WATER TEMPERATURES

Cold water temperature varies hugely, and while this isn't scientific, anecdotally, open water swimmers experience it in bands: 

0-11 DEGREES: Freezing.

Jumping in likely to impair breathing in the uninitiated, as breath comes in big jolting grasps and it feels like someone has clamped on an ice neck brace. Water has bite, skin smarts and burns. This is winter swimming. Limbs soon become weak - 25 metres can be an achievement - and only takes a minute or two at the lower end of temperatures before skin becomes a lurid purple-orange-red when you exit.

That said, the joy of swimming without a wetsuit at this end of the temperature spectrum is the cold water high: the pure exhileration and rush of endorphins that you get from getting in. Winter swimmers frequently become addicted to it, and it is sufficiently powerful that a 1-2 minute swim can leave you feeling good all day. Anecdotally winter swimming clubs like Serpentine Swimming Club and Tooting Bec Swimming Clubs report increased immunity and fewer colds. Swimming also improves circulation: regular outdoor swimmers tend to have very firm skin right into their 60s.

12-16 DEGREES: Fresh.

At this temperature triathlons start operating. In a wetsuit you may find you can swim comfortably for a while, outside of one the water is fresh, doable for the brave, and not a problem for hardened open water lovers.

17-20 DEGREES: Summer swimming. 

Lakes and more mature rivers reach this temperature over summer, during hot spells. Still fresh on entry, but comfortable picnic lazy-hazy summer swimming.

21 DEGREES PLUS: Warm.

You'd think that'd be a good thing, but on the rare occassions that river pools and shallow lakes reach these temperatures during hot spells, there is the odd sense that there's something missing.... the exhilerated feeling when you get out, that cold water 'tang'. On the plus side, some of you will be able to spend hours swimming without a wetsuit.

 30 DEGREES: Pool temperature.

Arguably unpleasant. Plus, as Rob Fryer comments, 'the sun is not invited'.

ACCLIMATISING

The secret to acclimatising is just to swim in it, often - at least once a week, and preferably two or three, gradually extending the time that you stay in the water.

It is easier to start your swimming career in summer at 16 degrees and above, and then keep on swimming as the temperature drops if you want to extend into autumn and winter. However, this is not essential.