z-risks & benefits of swimming – more info for swim intro

Additional information for participants in the lifeguarded outdoor swimming introduction sessions in the Healing Waters project, a project supported by the National Heritage Lottery Fund, part of The Brecks Fen Edge and Rivers Landscape Partnership Scheme.

This advice could also be useful to swimmers generally. When wild swimming, especially in the colder months, swimmers need to be aware of the risks of cold, and take time to learn how their body reacts and the limits in time and temperature that they can cope with. Many find that they adapt and become acclimatised to cold with regular swimming. Unless at an organised venue with safety cover, generally there is no lifeguard to help.

Read on about – the benefits of outdoor swimming, and – the risks in this article.

This video on Autumn swimming for beginners gives advice, https://www.youtube.com/watch?v=nI2GY1UpU78, and this one talks about the benefits and how your body reacts and adapts to cold water https://www.youtube.com/watch?v=0pXLF0sucDU



The water temperature in September, May or early June could be 13-16°. It depends on the weather in the days leading up to the swim session, with sunshine, rain, wind, overnight temperatures having an effect.

This will feel cold to you if you are not used to it. There is some brief advice below, and see advice from the Outdoor Swimming Society https://www.outdoorswimmingsociety.com/category/survive/cold/.

Open Water Lifeguards are trained to recognise when somebody is suffering from the cold and are fully trained in first aid and dealing with the effects of cold. Sometimes people don’t realise they are cold; if so a lifeguard would tell you to leave the water. And they are there to help if there are any problems.

The possible risks from swimming in or entering cold water:

  • cold water shock. Entering cold water quickly can cause an uncontrollable sharp intake of breath, an increase in breathing rate and an increase in blood pressure. It typically lasts up to a couple of minutes. To avoid problems, enter the water gradually and wait until your breathing calms down before swimming off.
  • cold incapacitation. Staying in cold water for too long if not used to it can make muscles weaker, making it harder to get out or to swim back if you are a long way from the shore.
  • hypothermia. Can occur if staying in cold water too long, and potentially afterwards – see after drop.
  • after drop. This happens when you get out of the water and your core temperature continues to cool for up to 20-30 minutes. It can cause you to shiver a few minutes after you finish swimming, which is the body’s attempt to generate heat. The important thing is to get dry, dressed and warm quickly after swimming, ideally before the shivering starts. Warm drinks and moving around gently can help warm you up.

There is more detailed advice on safety and outdoor swimming on the Outdoor Swimming Society website, Survive section, https://www.outdoorswimmingsociety.com/category/survive/, and in a note which you can download using this link: Risks to health and safety of outdoor swimming, and how to mitigate them (Word.doc, 5 pages)

And this page is on getting started in inland outdoor swimming

Other safety and health issues

  • Weil’s disease is rare, but you might need to be aware that if you develop any flu-like symptoms within 4 weeks after swimming you should see a doctor and tell them you have been swimming outdoors. If you’re concerned about contracting it the recommendation is that you cover any cuts with waterproof plaster, wash hands or use sanitiser before eating, and have a shower as soon as practical after swimming. More information about Weils disease https://www.outdoorswimmingsociety.com/understanding-weils-disease/
  • Ticks or other insects found in a forest environment: Use insect repellent, check yourself for ticks. Useful advice, including on ticks https://www.forestryengland.uk/safety-the-forest
  • Weather, trips and falls, including into the water – take care as in any outdoor environment, and dress appropriately for the weather. If you fall unexpectedly into water (in a situation where there is no lifeguard present), float on your back and try not to panic, call for help and make your way to the bank to get out. More on Float To Live https://www.respectthewater.com/

Benefits of swimming in cold water/outdoors, and research

Many benefits are claimed and reported for outdoor swimming, especially in cold water, for physical and mental health, as well as for other outdoor activities. As in this article about the benefits of swimming, and this one about the value of outdoor exercise generally https://www.essex.ac.uk/research/showcase/how-we-started-the-green-exercise-revolution.

Swim England have done more detailed research in 2017-2018 on the health and well-being benefits of swimming , and in 2019 on the Value of Swimming, https://www.swimming.org/swimengland/new-study-says-swimming-benefits-mental-health/, which can be downloaded from their website and found that outdoor swimming gives even more benefits than swimming indoors!

Other more detailed research is being done on outdoor swimming and health, including by this team led by Dr Mark Harper in Devon.

This video talks about the benefits and how your body reacts and adapts to cold water https://www.youtube.com/watch?v=0pXLF0sucDU.

This NHS Mood self-assessment page is available to anyone who would like advice about stress, anxiety or depression. It asks you to look at how you have been for the last 2 weeks, and gives links to advice and suggestions on when to seek help https://www.nhs.uk/conditions/stress-anxiety-depression/mood-self-assessment/

Evaluation and surveys in the BFER projects

A key purpose of the Healing Waters project and all of The Brecks Fen Edge and Rivers Landscape Partnership Scheme (BFER) projects , is to promote and to study the benefits of engaging with nature and outdoor activity, so throughout this and the other projects in the BFER scheme we will be asking participants about their experiences before and after project activities.

So we would like to ask you some questions before and at the Outdoor Swimming Intro session, and we will also ask permission to contact you after the event to follow up. Questions will follow a similar pattern to those used by Swim England in their research. Answering the questions is voluntary; we hope you would like to be involved.

You can read more about the wide range of BFER projects on the website projects page http://www.brecks.org/BFER/projects/, and can get in touch if you’d like to be involved in any of them.

swimmer sunshine river
Swimming in Autumn sunshine, river Thet
two swimmers with tow floats in river
Swimming in Autumn in the rain, river Little Ouse

swims and swim places, and related issues