pippa & V

What you need to know before you swim at Colwick Lake with WholeHealth

Swimming used to be an outdoor sport before we became conditioned to think it should be done in sterile tanks indoors. Perhaps thanks to the global pandemic, more and more people are venturing outdoors to swim. Our amazing members of WholeHealth have been rediscovering the joys, freedom and mindfulness of swimming outside in our beautiful Colwick Lake.

Your safety is our priority

We know that all of our members respect the power of the water and as with all things, the more we know and learn the safer we can be, as we continue to prepare for swimming during the autumn and winter months. If you’re hoping to keep your outdoor dipping or swimming going as the temperatures drop, make sure you read our simple guide to winter chill swimming at Colwick Lake.
  • With thanks to the Outdoor Swimming Society, an invaluable online resource for more information and support around Open Water Swimming.


  • Think before you swim. Use our safe entry and exit point,  to get in and out. Don’t jump or dive in unless you are extremely experienced in cold water. It is far safer to enter the water slowly to prevent ‘cold water shock’
  • It is possible to walk slowly into our lake and let the water inch up your body, so it’s the perfect place for cold water entry. This way you will gradually become accustomed to the water temperature
  • Make sure you’re visible in the water; we strongly recommend using a tow float or at the very least a brightly coloured hat-which will also keep your head warmer!
  • If you find yourself in difficulty RELAX and FLOAT on your back and alert our lifeguards by shouting HELP!


Water temperature Compared to indoor heated swimming pools, which vary in temperature from around 26 to 31 degrees Celsius, you are likely to be exposed to a much wider range of temperatures when swimming outside. In the UK, inland waters can be as low as zero in winter to as high as the mid 20s in peak summer. Coastal waters vary from low single digits to the high teens. The water temperature has a massive impact on how you swim and how long you can safely stay in the water. For the inexperienced or first time winter/chill swimmers, the biggest danger from sudden immersion in water that’s significantly cooler than you’re used to is cold water shock. This is the body’s initial and automatic response to rapid change in skin temperature. It causes, among other things:
  • a sharp intake of breath
  • an increase in breathing rate
  • an increase in blood pressure.
It typically lasts up to a couple of minutes. For the unwary, cold water shock can be deadly, especially if that sharp intake of breath occurs under water. In addition, if you have an underlying heart condition or hypertension then the sudden change in blood pressure may cause complications. Therefore, enter the water slowly and keep your face clear until your breathing is under control. The cold water response decreases with swimming experience and being mentally prepared. The second problem with cold water is that it can result in swim failure. To protect vital organs in the core, the body restricts blood flow to the limbs when in cold water. If this reaches extreme levels the arms and legs no longer function properly and you can’t swim. If you feel yourself slowing down or struggling to swim, get out, and warm up. The next risk is hypothermia. This occurs when you suffer a drop in core body temperature and can eventually lead to loss of consciousness and heart failure. The amount of time you can swim in cold water without suffering from hypothermia is determined by the temperature, your body size and shape and your experience, among other factors. Start with short swims to learn what your limits are and check in with Wales on the pontoon or the lifeguards who are trained to recognise the early symptoms of hypothermia, which you might miss. If your stroke rate slows down or you start to shiver, get out and warm up. When you finish swimming, you also need to be aware of what swimmers call the after drop’. This happens when you exit the water and cool blood from extremities starts circulating through your body again, lowering your core temperature. ThisIt  is why you often start to shiver a few minutes after you finish swimming. To minimise the risk, dress immediately starting with the top half of your body. Put on a hat and gloves and have a warm (non-alcoholic) drink. A wetsuit will not prevent cold water shock nor stop you from suffering hypothermia. However, it will help you to stay warmer for much longer, keep you afloat and, in most cases, allow you to swim faster. Also bear in mind that the water near the surface or away from the cold natural springs in the lake, especially on hot sunny days, can be much warmer than the water below. It is worth investing in some winter accessories to keep you swimming; neoprene gloves, bootees or a wetsuit for swimming, a dry robe, towel poncho and a hot water bottle for changing can all help make it more enjoyable.


From The Outdoor Swimming Society
Temperature Technical term Description
0 to 5 degrees Bloody freezing The preferred temperature for extreme winter swimmers. Causes pain and takes your breath away. Except for the very experienced, and only under strict supervision, swims should be limited to a few minutes. Enjoy the buzz when you get out.
5 to 10 degrees Really cold Typical lake and river temperature in early Spring and late Autumn. Still painfully cold and not recommended for anything other than very short swims (5 to 10 minutes) unless you are very experienced.
10 to 15 degrees Nippy or ‘not as warm as we like it’ Open water starts reaching these temperatures in late spring around much of the UK. At the lower ends, it will still feel extremely cold initially but longer swims are now possible. Experienced swimmers can manage several hours or more as the water approaches the mid teens but hypothermia is still a big risk.
15 to 20 degrees Fresh or ‘Alright once you get used to it’ The English Channel in summer. If you’ve only ever swum in a pool, this will feel cold but with a bit of experience and practice most people find this range comfortable, at least initially.
20 to 25 degrees Balmy Rarely reached in the sea around the UK, but often in inland lakes and especially Colwick Lake. If you’re a habitual wetsuit wearer then seriously consider removing it at these temperatures to avoid overheating. Very pleasant swimming.
25 to 30 degrees Stifling Like a swimming pool. Some open water swimmers find these temperatures too high for serious swimming. Make sure you have plenty to drink. Don’t wear a wetsuit.
30 degrees plus Hot Avoid strenuous swimming as there is a definite risk of heat stroke.
Note, swimmers have widely differing opinions about comfortable water temperatures and people’s bodies respond differently. Learn to trust your own experience and feelings.


Open water swimming is more enticing on hot sunny days but people do swim in almost all conditions, and different types of weather mean different pleasures, AND different risks you need to be aware of. In hot weather, there may be a big contrast between the air and water temperature that can catch you out and is suspected to be a cause of some open water deaths. Therefore, always enter the water cautiously. Remember that you can easily get sunburn while swimming so make sure you protect your skin with waterproof sunblock. Strong winds can make swimming conditions difficult. We all know that Colwick Lake can be windy and even white capping at times where small waves with ‘white caps’ break in the water.  Learning to breathe on both sides can help you cope better with waves and chop. Also be aware that a strong breeze increases the wind chill factor and you may get cold quicker than you expect. Finally, wind can make it difficult for lifeguards paddle boards and rescue boat, which is why sessions and events are sometimes cancelled or shortened. Swimming in the rain is no problem – you’re wet anyway – and it can even be very enjoyable to feel the drops on your back and to watch the water surface. Make sure you keep your clothes and towel somewhere dry for afterwards. And we will always get you out of the water before and during an electrical storm.


“One of the keys to cold water swimming is to have your kit ready, in the right order, for getting dressed after. Keep your swim hat on until you are ready to replace it with your bobble hat or other. Oh, and before you get in, stay warm for as long as possible. Crocs off last minute. Don’t wander around in shorts and flip-flops. You’re not impressing anyone.”
During the colder months you need to decide what you want from your lake swimming session and you have to be honest and realistic. Decide whether it’s:
  • A dip that may only last a couple of minutes or less, providing proven physical and mental health benefits
  • A short swim – one short loop (175m)
  • A longer swim – up to 30 mins
Be prepared to change your plans! The weather and your body will feel very different on different days. Many of our members will try and dip in “skins” meaning wearing a normal bathing costume or trunks and no wetsuit throughout the winter. This is fine as long as all the above information is taken into consideration. However, for the swimmers who want a longer swim then a wetsuit almost definitely becomes a necessity along with hat, gloves and boots. You can also have the best of both worlds and remove your wetsuit in the water for a short period of time before you get out to get the full cold water exhilaration.

See you at the lake!

Cat & Wales


  1. You app and website refers to the need for a towfloat and that I can get one from you. But I cannot identify how to do this? There’s reference to a “desk” but I don’t know where the desk is. And towfloats are not in your shop. Can you help me?

    1. Hi Alison,

      You can collect a tow float from us at the lake, and pay with credits or cash-we have 3 Puffin recycled floats to choose from ranging for £15-£25 in price. Hope to see you at the lake soon!

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