by Simon Griffiths, Outdoor Swimmer Magazine - @SimonDGriffiths

Outdoor swimming in winter is an acquired taste. Cold water isn’t just uncomfortable, it hurts. And it’s dangerous. So why get into it voluntarily? There must be a reason as the popularity of winter swimming is increasing every year and those who do it rave about the benefits.

The first thing to know about outdoor winter swimming is to approach it with a different mindset to pool swimming or swimming outside in summer. Winter swimming is not about fitness or training. Instead, it’s about an intense physical and mental experience that leaves you buzzing all day, along with the camaraderie that comes from doing something slightly eccentric. To start with, you need to abandon common sense and your preconceptions of normal behaviour. Then you must overcome, through force of will, your body’s reluctance to purposefully getting cold. Finally, once you’ve overcome those barriers, you’re in the water and the pain has been replaced by a glorious, electrifying tingle and you’re suffused with a sense of wonder about what you’re doing, you have to be mindful to get out and warm up before you become dangerously cold.

If this kind of experience appeals to you, where do you start?

The best thing is to find a group of people who already swim in winter as they can guide you to best places, advise you on how to stay safe and look after you while you swim. Facebook is a good place to start looking or see if your local lido stays open through winter. If you live in London you’re spoilt for choices including the ponds on Hampstead Heath, Parliament Hill Lido, The Serpentine, Tooting Bec and Brockwell Lido. Note that for several of these, you need to be a club member to use the facilities in winter.

Generally, unheated lidos are the ideal location for your first winter swimming experiences for safety and convenience reasons. My next choice would be the sea, provided conditions are calm. Keep in mind, however, that beach lifeguards are usually seasonal so there won’t be safety cover in winter. Increasing numbers of commercial venues (i.e. open water swimming lakes) now stay open in winter and offer the advantages of safety cover and (sometimes) warm showers and changing facilities. Rivers should be approached with caution as they are much less predictable. Higher flows may cause more dangerous currents than in summer, and the water quality may be worse, especially after heavy or prolonged rainfall.

The main risks from cold water are cold water shock, swim failure and hypothermia. You also need to be aware of something called “after-drop”.

Cold water shock is the body’s natural physiological response to sudden immersion in cold water. It causes a sudden involuntary sharp intake of breath, gasping, a sense of panic and an increase in blood pressure. For the unprepared, it can result in drowning.

The good thing about cold water shock is that its impact reduces once you have experienced it a few times. You can also mentally prepare for it, which again reduces the impact and avoids the panic element. Finally, it only lasts a couple of minutes. It’s at this point that cold water swimming starts to feel amazing.

The next thing to be aware of is that your body will try to preserve heat in your core by restricting blood flow to your limbs and periphery, so these are the first things that get cold. As your muscles get cold, their strength decreases, and this hampers your swimming ability – this is why people’s time for an Ice Mile (a mile swum in water of less than five degrees celsius) is typically much slower than their time for swimming a mile in a heated pool. There is a danger that your muscle power decreases to the point where you can no longer swim, which is an obvious drowning risk.

At a certain point, your body can no longer protect your core and it starts to cool down. This is the onset of hypothermia, which will eventually lead to death if you do not leave the water and get warm again. One of the dangers with hypothermia is that it also impairs your mental abilities and judgement. You can think you’re fine, but you’re not. If you start shivering violently, leave the water immediately. If you are with another swimmer and you suspect they are becoming hypothermic, insist they leave the water, whatever they say.

Finally, once you leave the water, cold blood from your extremities returns to your core, which means your core body temperature continues to drop for something like 20 to 30 minutes after you have finished swimming. This is known as after-drop. You should therefore not attempt to drive a car or ride a bike immediately after swimming but wait until you are properly warm again. You will feel good (and probably warm) as soon as you leave the water but this is deceptive. It’s important to dress quickly to minimise after-drop and speed your recovery.

Despite these dangers, cold water swimming can be really fun and enjoyed safely provided you know the risks and prepare and act accordingly.

For more outdoor swimming advice and training tips, please visit Outdoor Swimmer’s website at Outdoor Swimmer magazine is published 12 times a year with subscriptions starting from £12.45 per quarter.

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