Acclimatisation | The most important Open Water skill

What is acclimatisation?

Acclimatisation is the process Open Water swimmers use to allow their body to adjust to cold water. Unlike your swimming pool – you can’t really just dive in. It’s always best to allow your body to get used to the water gradually and to follow a number of steps to allow your body, your muscles and your mind adjust to the Open Water environment. And the acclimatisation process is one of the first things we work through with our Open Water Virgins – it really is one of the most important Open Water skills.

Why is it so important?

Acclimatisation is important because it helps you to mitigate the risk of ‘cold water shock‘ – the adverse reaction of the body to very cold water, often triggered by an unexpected fall or a rushed entry into cold water.

Cold water shock aside, if you start swimming without acclimatising then your swim simply won’t be as effective or as smooth as it could be – your muscles won’t be used to the water and you won’t be swimming at your best. And so you really should acclimatise whenever you swim in Open Water and especially before an Open Water race – this is something we run through with our Open Water experts and nearly every Open Water swimmer has an experience (usually not the best) of forgetting to acclimatise before a race.

How to acclimatise?

  1. Splash your face, hands and your body with the cold water
  2. Enter the water gradually (ideally via a ramp or a shallow gradient)
  3. Once in the water, let some water down the front of your wetsuit – yes, it might sound like we’re being a bit mean here BUT this is the best way to cool your body down quickly.
  4. Practise floating on your front and back, relax your muscles, your lungs and let your wetsuit do most of the work
  5. Practise breathing out into the water (using your mouth). Follow the breathing drill below to allow your lungs to expand and to counteract the constricting effects of your wetsuit:

Breathe out for 5 seconds with a calm inhale in between each exhale (repeat 10 times)

Breathe out for 10 seconds (repeat 10 times)

Breathe out for 20 seconds (repeat 10 times)

Top acclimatisation tips:

  • Practice regular cold water submersion – cold baths or showers is a great place to start!
  • Always allow enough time before a race or swim to acclimatise properly
  • Know your own body and recognise the symptoms of cold water shock
  • The more you acclimatise the easier it becomes!
3 replies
  1. Jane Johnson
    Jane Johnson says:

    I agree – this is an important part of OW swimming. So why do race organisers often not take this into account & rarely allow time to acclimatise before the race start? You’re often not allowed in the water before the start & worse, in some triathlons, it’s a mass start from land & you’re expected to swim straight off! I swim in OW often but had panic attack from a mass start in an OW triathlon due to lack of acclimatisation.

  2. Harriet
    Harriet says:

    Yes I learned the hard way on my first ever cold water swim.. Got in too quickly and had severe chest pains and breathing problems.. And thus discovered I had high blood pressure .. Not a good mix! However now sorted and enjoy many river swims

  3. ig
    ig says:

    Oh my goodness! Awesome article dude! Thanks, However I am going through difficulties with your
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