Introduction

Cold water therapy, or the practice of exposing yourself to cold water to provide health benefits, has seen a surge in popularity in recent years. Athletes have increasingly been using ice baths after exercise to enhance recovery, and after public pools shut during the COVID-19 pandemic, the number of people joining the Outdoor Swimming Society rose by 36%. This rise in popularity has continued; a survey conducted at outdoor swimming events in 2022 found that 20% of participants had taken up the sport in the past 12 months. 

So what is it about taking a dip in freezing water that is getting people so excited? Cold water therapy can support our well-being in many ways, for example, by increasing alertness and energy, improving our mood,¹ as well as reducing muscle soreness and recovery time post-exercise,² and helping us manage both weight and pain.³ In this article, we’re going to outline how you can incorporate cold water therapy into your routine to supercharge your health and well-being.

Methods of cold water therapy

There are a few different ways to get your refreshing hit, each with its own pro’s and con’s:

1. Cold shower- Exactly what it sounds like, getting under a cold shower is typically the most accessible method.
2. Cold-water immersion (CWI)- As simple as putting your whole body in cold water, however how you do this and to what depth gives CWI some nuance. Most research has looked at participants immersing themselves up to the neck at a controlled 10-15℃ (50-59℉) for 5-15 minutes^4,5. There are more expensive temperature-controlled baths available, but a simple barrel filled with iced water, an unheated pool, or a lake also works. You don’t have to put your whole body in either; research has shown benefits when participants were only immersed in the hips.⁶
3. Contrast therapy- This involves immersing yourself in alternating warm (e.g. 35-40℃ (95-104℉)) and cold (e.g. 10-15℃ (50-59℉)) baths. Users typically alternate the temperature every 1-2 minutes, for a total duration of 6 to 15 minutes.^5,7
4. The Wim Hof Method- A protocol developed by Wim Hof, a Dutch motivational speaker and athlete, who was nicknamed ‘The Iceman’ for holding multiple world records for cold exposure. The Wim Hof Method centres on three ‘pillars’: breathing techniques, cold exposure and meditation. Studies looking at the benefits of this method have mixed results, with some showing no change in cardiovascular or stress responses,⁸ while others see a benefit in reducing stress that was not present for cold water therapy or meditation alone.⁹

Creating your cold water therapy protocol

Choosing the best method for you

The method you choose will likely depend on factors like availability, time, experience and money. It is recommended to start with cold showers first, both to reduce the risks of cold water (covered later), and because it has the lowest barrier to entry. If you’re keen to progress beyond this, CWI or contrast therapy is recommended, as both seem to be equally as effective, at least for managing pain.⁶ Showers are less effective than both CWI and contrast therapy, likely because less of your body is in contact with water, and there’s no water pressure from being submerged.^5,10 Your choice between CWI and contrast therapy depends on what is cheapest or easiest to implement. Your local sauna may have a warm pool and cold plunge pool for contrast therapy, or you may have a local wild swimming group for CWI.  

What temperature should I aim for?

Although we’ve outlined the typical temperature ranges used by researchers to provide benefits, the temperature you choose depends on your tolerance. In fact, sudden exposure to the cold has risks associated with it, especially if you’re inexperienced.¹¹ Start warm and gradually decrease the temperature from one session to the next. Once you feel safe, we recommend following this rule of thumb from Professor Andrew Huberman, a neuroscientist at Stanford University:

“The key is to aim for a temperature that evokes the thought, ‘This is really cold (!), and I want to get out, BUT I can safely stay in.’ For some people, that temperature might be 60°F, whereas for others, 45°F.”

How often and for how long should I do cold water therapy?

The answer to this depends on what your goals are. If you’re looking to use cold water therapy for broad health benefits, a research paper on CWI found that 11 minutes per week split into two to four sessions led to optimal increases in metabolism.¹² However, if your aim is to improve exercise recovery, use cold water directly after exercise, using the durations outlined in the ‘methods of cold water therapy’ section. 

What time of day should I do it?

For those looking to improve their energy, alertness and focus, you’ll likely find the most benefit at the start of your day. However, including it at any time in your routine will yield benefits.  

For those looking to improve their exercise recovery, studies recommend ‘immediately’ or ‘within 30 minutes post-exercise’, so include it as soon as is practical.⁵

Despite these recommendations, two things should be noted. Firstly, cold exposure leads to core body temperature increases, which is highly associated with waking from sleep.¹³ While cold water therapy is better late than never, consider avoiding it or rescheduling it if you find it’s affecting your sleep. Another consideration is that multiple pieces of research suggest cold water therapy can reduce muscle growth and strength improvements following exercise.^14,15 If this is your goal, reschedule it or wait 4-8 hours after training. 

Safety risks and considerations

Before you jump ‘head first’ into cold-water therapy, there are potential risks to consider as well as health conditions that may make it dangerous. 

General risks

The following are risks that can apply to everyone, particularly those who are new to cold water therapy.

Minimising risks

Here are a few tips to minimise the risks above: 

1. Before starting cold water therapy, consult your doctor
2. Start with cold showers and tepid water, then gradually reduce the temperature across sessions and finish with a temperature that is uncomfortable but safe
3. Never go for a cold water swim on your own
4. Warm up as soon as you leave the water. See the advice from the Outdoor Swimming Society on ways to do this safely (very rapid changes in heat e.g. a very hot bath after CWI, can be just as dangerous as hypothermia)

Health conditions that can make cold water therapy dangerous

While we recommend you always consult your doctor before starting cold water therapy, patients with any of the conditions below should take extra care. 

Summary

Cold water therapy is the practice of exposing yourself to cold water by different methods to provide benefits like pain relief, improving mood and reducing recovery time after exercise. 

Practitioners can implement it by using cold showers, cold water immersion, contrast therapy or the Wim Hof Method. While cold water therapy is generally safe, users must be aware of risks like hypothermia, the cold shock response and cold panniculitis, and follow the guidance outlined here to minimise them. Those with heart and lung conditions, cold urticaria or Reynaud’s syndrome should strongly consider avoiding cold water therapy. 

Keywords

• Cold water therapy
• Cold-water immersion (CWI)
• Contrast therapy
• Wim Hof Method
• Cold shock response