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Cold water & fast currents

Updated: Apr 7, 2022

The challenges of open-water swimming in winter

We all respond differently to cold water and if you’re new to cold water swimming, it’s good to read around the many articles and get informed because there’s a lot to be aware of. If you’re an old hand, it’s interesting to compare notes. Here’s our contribution – not offering advice but sharing some experiences in the hope it helps you decide how you’re going to approach swimming safely and happily in the winter months.


Our regular spot is in the Thames and the Thames in spate is a foul-mouthed creature that rushes a torrent of abuse at swimmers: fast waters containing run-off from farms and raw sewage, also branches and other debris, mostly hidden below the surface. This can be true in the summer but is obviously more common in the winter.

Last autumn and winter, the floods seemed to last several months and we kept ourselves to one sheltered corner in front of the lock. Once the water drops below about 10 degrees, the accepted rule of thumb for skins swimmers is to stay in one minute for every degree. Even when we went longer than that, we didn’t swim far and our little corner was enough to enjoy the energising effect of cold water.

We took our risk with pollutants – although thoroughly covered any cuts (which we do anyway). As a group, we watched out for each other and knew well our different reactions and tolerances to the cold. We understood that submerged branches might reach us but, rightly or wrongly, felt that, where we swam, we were in a position to handle the situation if anyone was struck. Luckily, we didn’t have to test our confidence on this. Meeting a fast-moving log head-on when swimming doesn’t bear thinking about.

Winter skin-swims don’t get us fit but the experience is beyond exhilarating and provides a great sense of achievement. Right now, we all need all the support we can find to keep emotionally strong and cold water swimming is a great boost to our mental health.

WOSB articles on the joys of cold-water swimming - Cold water swimming: the logical choice A personal justification for cold-water swimming - The benefits of cold water swimming: the facts A light look at the scientific reasons why cold-water swimming is good for mental health - Clawing back to warmth A memory of post-swim changing one particularly cold, wet day

If nothing else, by keeping acclimatised to cool waters, we’ll be ready to pick up the training early in the spring. But what of our swim training? Is there somewhere we can do this?


Ordinarily, pool-swimming a couple of times a week keeps us swim fit. This year, to keep socially distant, especially indoors, we’re choosing not to use pools. To train, we’re using a ‘performance lake’; it’s more local to us than our closest (much bigger and much more beautiful) NOWCA venue and has heaps more time scheduled for swimming. It’s not a place to feed our love of meandering banks with spectacular views and an abundance of wildlife but we will live off the memories of those swims and look forward to more next year.

WOSB articles appreciating the blue-green world - Wild swim and wildlife Observations of nature from the river - A river ramble A late spring swim upstream

The performance lake is clean and safe – there’s even a lifeguard. The water feels clean enough that if we forget to rinse down the neoprene afterwards, it’s probably not a problem. There are changing rooms and showers. It’s very, very civilised and not an ideal spot for wild swimmers but it’s a brilliant compromise – and fantastic for anyone just starting out on cold-water swimming who might be a little less keen. We’ll lose a little less swim-fitness if we do this once a week. And anyway, our favourite events don’t begin until July so there’s time to pick up the fitness next year.

WOSB articles on one of SwimOxford’s events: The swim-run - The Lock-to-lock swim run (A serious competitor enjoys the event) - The Oxford Swim-run: A half-stumper’s experience (A less serious competitor enjoys the views and the cake) - A local swim-run adventure (another serious competitor is thrilled to race safely during the pandemic)

To train in the winter, we dig out the neoprene: wetsuits, hats, booties and gloves. It was 12 degrees in the lake last week and we did 1200 metres. For three of us, this was fine; we were warm and would have stayed longer if work wasn’t waiting. But for one swimmer, it was enough; she was cold. We’re all different so what kit do you personally need?


It just keeps getting colder in January so if you’re not kitted up before Christmas, here are some thoughts on what you could to add to your list. No reviews – we don’t test different brands – but there are heaps of reviews elsewhere so these are just ideas of what to look up.

For people who struggle with dizziness and sickness in cold water, a great piece of kit is a neoprene cap. Not everyone seems to need this – and it’s not necessary if you don’t put your head in the water. Caps with chin straps protect ears a little too (but a downside: it’s probably impossible to look good in a photo when you’re wearing one of these).

As it gets cooler, ear plugs (a handy stocking filler) are a good idea.

Wetsuit. This choice will depend on how cold you get, what you can afford, and what room you have room to store kit. Ideally, try a few – order a bundle if a company will take returns, or find a swim location that does try before you buy. There’s a huge choice of suits these days and the ideal would be to have a suit for every occasion: a triathlon wetsuit, a swim-run suit, a thermal suit and, if you can find the right location, a birthday suit... Old wetsuits can be patched up to keep going a little longer with Black witch (another stocking filler).

Booties/socks and gloves – do read the reviews; you get what you pay for and it’s probably only worth getting these, particularly gloves, if you’re prepared to pay. The gloves that have come top in a couple of reviews were pricey but have not disappointed.

Those big robe things. The most critical action after a cold dip is to change into warm clothes as fast as possible. Often, changing under a cheap towelling robe and piling on multiple layers fast, finishing with a down coat is fine – no robe required. On the coldest and/or rainiest of days, the big robe goes on top of all of that. For most of our swims, we can survive without a robe – although we fantasise about more rugged swims when we might be pleased of one. Note that they are expensive and can be bulky to carry around or store.

Fins. Why not? To push you through those currents if you feel that’s safe. It might mean you can go a bit further than you would manage without so that you can have a longer swim and a change of view.

WOSB article on fins - Fun with fins (The merits of different designs of fin)

A few weeks ago, a boater commented that he’d seen our tow floats long before he saw us so when we’re out on the river with boats around, they’re a must for visibility. In the winter, when we’re not swimming so far and the boaters aren’t out in force, tow floats might not seem as important for visibility but they’re no bad thing to have for safety – and if you’re a little nervous, are great for reassurance. Suddenly, there are many different designs available. You may as well have one you can put some kit in – just car keys and phone; unless you’re planning a walk and a swim (towing your walking clothes), which is a nice way to vary the views a bit.

Once you’re on land, you might want to make sure you’ve got yourself a good flask for hot drinks. Also layers and layers of clothes that are easy to pull on. No buttons (or hook-and-eye devices that do up at the back – impossible!). And warm socks and boots; feet seem to take ages to warm up. And gloves. And a hat.

So you’ve got the gear; is it really a good idea?


You’ve heard about the various health benefits associated with cold water swimming (including the latest research that suggests it might delay dementia) and you need to weigh all these up against the many hazards. Do people who understand the risks as well as the benefits actually do it? Some do:

Tricia Greenhalgh, Professor of primary healthcare at the University of Oxford and a practising general practitioner. A key figure in getting us all to wear masks (and not even for swimming) and a regular Thames-swimmer (Oxford branch): ‘Water temperature plummeting but with thermal gloves and booties I’m OK for a few more weeks.’

Dr Chris van Tulleken, Member of the Royal College of Physicians, Honorary Associate Professor in the Division of Infection at UCL and an infectious diseases doctor at the Hospital for Tropical Diseases and University College Hospital, London. A leading BBC science presenter: ‘The only time I feel totally calm is swimming in the sea in winter.’

Our top tips come down to this:

Get informed.

Get prepared.

Get in.



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