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How to acclimatise to cold water 

How to acclimatise to cold water

Recently we have been seeing a new wave of open water swimmers, which is amazing; however, it is crucial to understand how to acclimatise your body to chilly temperatures and cold waters.

Without properly preparing your body, you can put yourself at risk in the icy waters. This article will help you understand how to safely prepare and enter cold water.

Follow our top tips for cold water swimming to enjoy this thrilling activity without danger. So, learn to swim safely and acclimatise before taking your first dip!

What is acclimatisation?

Acclimatisation is the process of adapting to new and potentially harsh conditions while allowing optimal fitness levels.

Acclimatising to extremities, such as cold water and wind, is important to ensure your body can withstand the shift in temperature without having adverse side effects.

Your body will naturally try to acclimate to new environments; however, you can take steps to assist this process.

How does your body react to cold water?

When you submerge your body into cold water, you may experience what is known as cold shock.

Cold water shock is when cold receptors close to your skin’s surface recognise the temperature shift and incite a physical response.

The cold-water immersion increases your blood pressure and heart rate, which may make you start shivering, lose your breath, or uncontrollably gasp.

You can control your cold shock by learning how to acclimatise to cold water, as there are ways to reduce the impact of freezing temperatures.

Keep reading to learn the best way to acclimatise to cold water.

How does your body react to cold water?
Swimmer by a cliff

How to acclimatise to cold water

If you are serious about starting cold-water swimming, then you need to consider the following steps to safely acclimatise to cold water:

1. Practice at home

You can practice acclimatising at home by taking cold showers. Start by turning the shower cold for thirty seconds at the end of your normal wash; then, you can keep building up the time spent in the cold water.

After you become more tolerant of this, you can try taking a cold bath and add ice to your bath after a while. Once you have built up your tolerance at home, you may be ready to try the ice-cold waters in the UK.

2. Consider a neoprene wetsuit

Neoprene wetsuits can help you acclimate to cold water, providing insulation to keep your body temperature regulated and warmer.

Other neoprene equipment, such as hoods, socks, booties, and gloves, are beneficial and can reduce your cold shock response by insulating your body. Neoprene traps a thin layer of water close to your skin which remains warm and helps regulate your core temperature.

There are inexpensive neoprene gloves, suits and booties on the market, so if you are concerned about losing too much body heat, we recommend having a look!

Consider a neoprene wetsuit
Man using wetsuit in the sea

3. Get comfortable with discomfort

The first time you enter cold waters, especially in the autumn and winter, you may be shocked by your body’s reaction. One of the most important tips is to remain calm and recognise it is a normal feeling.

The worst thing you can do is react and panic about the discomfort you may experience. In the words of Redbull, “You’ve got to get comfortable with being uncomfortable”.

So, take it easy, acknowledge and accept your response, and don’t push yourself too hard. You don’t need to submerge or dive on your first go. Wait until you understand and recognise your response before you go full out.

4. Control your breathing

Getting into cold water can cause you to become short-breathed and panicked; this can be dangerous once you swim.

Again, the key to combating your breathing is to take it slow. Once you are in the water, float around for a couple of minutes to assess how your body responds before you swim.

Take long, deep and stable breaths to calm yourself; when your breathing has settled, you can consider pushing your cold swim to the next level.

You will experience your cold shock response almost immediately, and if it is too much or you start to feel ill, you must get out and dry off.

5. Understand your body’s reactions

A great way to remain calm when you experience a cold shock response is to educate yourself on the physiology of your body’s adverse responses.

You may feel like you are becoming hypothermic; however, in reality, you are experiencing vasoconstriction of the capillaries. Once you know what is happening inside your body, you will understand your body’s reaction to adjusting to the new climate.

Much research has been carried out into the body’s response to cold water immersion; check out these articles to educate yourself before you go open water swimming.

6. Warm-up immediately

Your body will continue cooling down once you exit the water; therefore, you must dry off and change into warm clothes after your cold swim.

Many cold water swimmers use a dry robe to get dry and warm after swimming in cold water, as they also give you privacy to change discreetly wherever you are. Always have plenty of warm clothes in your tow or car in case any get damp.

Once you have warmed up slowly, you can take a hot shower but refrain from doing so until your body is no longer cold. You must acclimate to cold and hot water, so take your time warming up.

Cold water swim dry robe
Man using dry robe

7. Rehydrate

Swimming in cold water causes your body to direct blood to your core, and it does this by filtering fluid out of your blood. So, when you swim in the cold, you may feel the urge to urinate.

As you lose fluids as you swim in a cold water temperature, you need to rehydrate once you finish your swim. Many tow floats come with pockets to hold water bottles, so you can drink even when in the middle of the water.

Never try to drink the water you are swimming in, as you won’t know if it is safe. Sea water is high in salt and will only make you more dehydrated!

8. Practice makes perfect

Your first time will always be the hardest, as you are not used to being in water that cold! Practice makes perfect, so it is good to try to swim every week, if possible.

Your swims do not need to be long or intense, but exposing your body to colder temperatures weekly will help you get used to this environment.

There are many health benefits to cold water swimming, and if you can make this a permanent hobby, you will be less anxious the next time you dip in the icy waters.


Can swimming in cold water give you a headache?

When you swim in cold water, your blood vessels will constrict, giving you a headache. As the blood vessels spasm, you may experience pain similar to having a brain freeze.

Do not panic; this is a normal physiological response and nothing to be concerned about. If you get a headache in the water, remove any goggles, get out, get dry, and get warm.

You can take standard pain medication, such as paracetamol, and then relax for the rest of the day until you feel better.

Why do I feel tired after cold water swimming?

When you swim in cold water, your internal temperature will drop, and your body will have to expend more energy to keep you functioning and moving, which will make you tired.

The more energy you use, the more tired you will be, so it is normal to feel greater fatigue when you swim in cold water than when you swim in warmer waters.

To compensate for the added effort, take it slow and don’t push yourself as hard. You won’t be able to swim as far as you might in a pool, which is typical. Cut the duration of your swim until you have properly acclimatised to your new and extreme surroundings.

Why do I feel sick after cold water swimming?

As cold water swimming causes your blood vessels to constrict, when you exit the water, your vessels will eventually start to dilate. Vasodilation can cause orthostatic hypotension, nausea and dizziness.

You may also feel sick and light-headed if your wetsuit is too tight, so ensure you have the correct sized wetsuit and maintain your suit to keep it in optimal condition.

Another cause for nausea is if you start to panic in the water, making you hyperventilate and dizzy and weak. Remain calm and wait until your breathing has slowed before you swim into the water.

To reduce your nausea, you can eat something like a slice of toast or a protein-packed sandwich and drink an energy drink or cup of tea.

Why do I feel sick after cold water swimming?
Slices of toast

What are the signs of hypothermia?

The main signs of hypothermia include the following:

  • Shivering.
  • Exhaustion.
  • Confusion.
  • Shaking hands.
  • Memory loss.
  • Mumbled speech.
  • Drowsiness.

If you experience any symptoms, you must exit the water and warm up.

Suppose you are wondering how to avoid hypothermia. In that case, the short answer is only to enter the water for a short time, less than ten minutes, unless your body has sufficiently acclimatised.


Whether you are reaching the summit of Everest or swimming in the cold, acclimatising to freezing water is extremely important.

Diving straight into cold waters can be dangerous and potentially lethal. Hypothermic adaptation is essential if you want to swim in the winter.

With our tips on how to acclimatise to cold water, you will know how to safely prepare for cold water swimming and understand your body’s response to the cold.

Always consult your doctor if you have any health issues, such as a heart condition, before you attempt a cold water swim. Some health conditions may make acclimatisation more difficult, and safety should be your primary concern!