In the quest for peak physical condition, enhanced mental health and cognitive function, and an endless supply of Instagram-friendly video content, ice baths have surged in popularity over the last couple of years, championed by everyone from world-champion athletes to wellness gurus to your least-favourite influencer.

Despite its now near ubiquitous presence on social media, cold water immersion therapy is an ancient practice, passed down through the generations for its huge number of perceived physical and mental health benefits. The scientific research is now confirming these anecdotal claims, with regular cold exposure proven to enhance post-exercise recovery and reduce stress and anxiety in the short-term, as well as improve heart health, immunity and metabolic function in the long run.

In short, the “bio-hack bros” might be on to something: taking regular ice baths could be the key to unlocking the fitter, healthier, happier and longer life you want. Here’s everything you need to know.

What is cold water immersion therapy?

Cold water immersion therapy involves submerging the body in extremely cold water to induce physiological responses that can promote various health benefits. This practice, often referred to an ice bath, is popular among elite athletes, fitness enthusiasts, and anyone seeking general health improvements.

The underlying principle of cold water immersion lies in its ability to significantly lower the body’s temperature quickly. This rapid cooling elicits a cascade of physiological reactions. Initially, the body’s sympathetic nervous system activates, which increases the release of stress hormones, including adrenaline. This surge leads to vasoconstriction – the narrowing of blood vessels – which helps to reduce inflammation, decrease muscle soreness, and temporarily increase blood pressure.

Additionally, the cold exposure stimulates the vagus nerve, which controls the body’s rest and digest system. Activating this nerve can enhance parasympathetic responses, leading to decreased heart rate and increased relaxation after the initial stress response subsides.

So ice baths really do improve my health and fitness?

Yes! Cold water immersion therapy, such as ice baths, leverages the body’s natural physiological response to extreme cold to enhance health and wellness. When submerged in cold water, the body undergoes a shock response, which initiates several beneficial processes. Initially, blood vessels constrict to preserve body heat, redirecting blood from the periphery to the core. This vasoconstriction is not just a survival mechanism but enhances blood circulation when the body rewarms, flooding cells with nutrients and oxygen.

The cold also stimulates the central nervous system, heightening alertness and clarity, and increases the production of endorphins (often referred to as the body’s natural painkillers), which can elevate mood and well-being.

This biological response not only supports immediate physiological resilience but also contributes to long-term health benefits by enhancing immune function -by increasing levels of white blood cells and circulating cytokines, which help the body fight off infections – and improving metabolic health and function.

What does the latest research say on cold water immersion therapy?

Recent studies have illuminated many tangible benefits of cold water immersion therapy. For instance, regular cold immersion significantly reduces muscle soreness post-exercise compared to no intervention, according to research published in the International Journal of Sports Medicine.

It can also improve antioxidant capacity of the body, suggesting a strengthening of the body’s defence system against oxidative stress, according to another study published in the Frontiers in Physiology journal.

These studies and many others, including those by Unfiltered contributor Dr Susanna Søberg, a world-leading authority on thermal treatments, confirm that consistent exposure to cold water can enhance post-exercise recovery, boost immune response, and potentially increase longevity by mitigating oxidative stress.

What are the biological mechanisms activated by exposure to very cold water?

Cold exposure activates a cascade of biological mechanisms that confer various health benefits.

One primary response is the activation of brown adipose tissue (BAT), a type of fat that burns calories to generate heat. This process, known as thermogenesis, not only helps maintain body temperature but also improves metabolism and fat burning capabilities.

Cold exposure also triggers the release of norepinephrine in the brain, a hormone and neurotransmitter involved in increasing focus and energy levels, while reducing inflammation.

And the hypothalamic-pituitary-adrenal (HPA) axis is stimulated, enhancing the body’s stress response and potentially lowering chronic stress levels when practiced regularly. These mechanisms collectively bolster the body’s resilience and efficiency, reflecting the profound impact of cold therapy on overall wellbeing. See below for in-depth details on the major short- and long-term physical and mental health benefits.

What is the optimal temperature and duration for a health-boosting ice bath?

To maximise the benefits of an ice bath while minimising potential discomfort and health risks, the optimal water temperature is between 10-15°C (50-59°F).

Immersion times can vary depending on individual tolerance and specific goals, but a general guideline is to aim for 10 to 15 minutes. This duration allows for sufficient exposure to trigger the body’s cold shock response, including the release of endorphins and activation of the circulatory system, without overly stressing the body.

However, you may have to take some time to gradually build up your tolerance to the cold. Some experts, including Dr Søberg, recommend starting with very cold showers to get your body acclimatised to the cold. From there, you can start taking fully immersed ice baths, starting with just a couple of minutes, then increasing the duration over time.

Remember that prolonged exposure to very cold temperatures can increase risks of hypothermia, especially without prior acclimation, and pose additional health risks for people with heart problems and other conditions (see below for more details on the health risks of ice baths).

How many ice bath sessions are recommended per week?

The recommended frequency of ice bath or cold water immersion sessions can vary widely depending on your objectives, physical condition, and tolerance to cold exposure. Here are some general guidelines based on common goals:

Post-Exercise Recovery: Athletes often use ice baths after intense training sessions to aid in muscle recovery and reduce inflammation. For this purpose, it may be beneficial to take an ice bath after strenuous workout days, which could range from 1 to 3 times per week depending on the training schedule.

General Wellness: For those using cold water immersion to enhance general health and stress resilience, a regular but moderate schedule might be effective. This could mean 2 to 4 sessions per week, allowing for gradual exposure and sufficient recovery time between sessions.

Chronic Pain Management: Individuals using ice baths for chronic pain or inflammation might benefit from more frequent sessions, potentially near daily, depending on how they feel and the specific health conditions being addressed.

Whichever your circumstances, it’s crucial to listen to your body and adjust frequency based on personal responses and goals. Starting gradually and increasing frequency as your body adapts is always the best approach.

How do I take an ice bath?

Many companies specialise in at-home or in-garden tubs specifically designed for cold water immersion therapy. However, many of these are expensive and require on-going maintenance, so a cheaper option is to use your bathroom tub to take an ice bath. Here’s how to do that safely and effectively:

Here’s our handy five-step guide so you can do it safely and effectively:

Preparation: Fill a bathtub with cold water. Aim for a water temperature around 10-15°C (50-59°F). Add ice until the water reaches the desired chilliness. A good rule of thumb is to use enough ice to make the water visibly icy but not so much that it becomes unbearable.

Timing: Before you begin, set a timer. For beginners, start with anywhere between 2 to 10 minutes. As you get used to the sensation and understand how your body reacts, you can gradually increase the time up to 15 minutes.

Immersion: Enter the bath slowly. Start by sitting in the water, then gradually immerse the rest of your body. It’s important to keep your upper body – especially your heart and lungs – above the water if you find the full immersion too intense initially.

Safety: It’s essential to listen to your body during the bath. If you feel too uncomfortable or start to shiver uncontrollably, it’s time to get out. It’s normal to feel a sharp cold at first, but this should subside into a numbing sensation.

Warming-Up: After getting out of the bath warm-up gradually. Gentle warming methods, like wrapping yourself in a warm towel and moving to a warmer environment, are recommended. Avoid using direct heat sources immediately and avoid abrupt temperature changes.

How can I get better at taking ice baths?

Here are some instant-impact and zero-cost ways to better endure any type of cold water exposure:

Start Gradually: Begin with shorter durations and slightly warmer water. Gradually decrease the water temperature and increase your immersion time as you acclimate.

Be Consistent: Regular practice is essential. Try to incorporate ice baths into your routine consistently, perhaps after workouts or on a set schedule throughout the week.

Prepare Mentally: Mental preparation before an ice bath session will go a long way in making it more bearable. Remind yourself that the discomfort is temporary and focus on all the short-term and long-term benefits you’ll get by seeing it through.

Controlled Breathing: Focusing on your breath can help manage the initial shock and discomfort. Practice deep and controlled breathing to calm your mind and body. Techniques such as box breathing or guided meditation can be very effective.

Track Progress: Keep a log of your ice bath durations and temperatures, as well as how you felt during and after each session. This can help you adjust your approach and see your progress over time.

Should I take an ice bath if I have a cold, flu or fever?

No, taking an ice bath while experiencing a cold, flu, or fever is not recommended. Although cold exposure has been studied for its potential health benefits, such as reducing inflammation and improving immune function, the sudden drop in body temperature from an ice bath can exacerbate symptoms and may prolong illness.

Research published in the journal PLOS One suggests that cold exposure can suppress immune function, potentially making it harder for the body to fight off infections. And exposing yourself to extreme cold while already unwell may increase the risk of complications, such as respiratory issues or hypothermia.

Instead, focus on rest, staying hydrated, and seeking medical advice if necessary. Utilising other methods like warm baths, herbal teas, and plenty of fluids can provide comfort and support the body’s natural healing processes.

How do I incorporate ice baths into my health and fitness routine?

To safely and effectively incorporate ice baths into a wellness routine, consider the following best practices. Start gradually, especially if new to cold exposure, by initially immersing only part of the body and for shorter durations. As tolerance builds, you can gradually increase both the immersion level and time.

It’s also beneficial to have a warm shower available to gradually rewarm the body post-immersion, aiding in the recovery process and enhancing the circulatory benefits. Monitoring the body’s response to the baths is crucial and any signs of discomfort or stress should not be ignored.

Finally, integrating ice baths as a regular part of a post-exercise routine can maximise recovery benefits, especially after intense physical activities. Consistency is key, because the body adapts over time to the stress of cold exposure, thus increasing the health benefits.

What are the mental health benefits of regular cold water immersion?

Short-term benefits include an immediate boost in mood due to the release of endorphins, often referred to as the “high” that follows the initial shock of cold. This effect can combat feelings of depression and anxiety by providing a natural and invigorating rush.

Over the long term, regular cold water therapy can significantly impact resilience to stress. The repeated activation of the body’s stress response in a controlled environment, such as during cold exposure, can enhance the ability to manage other forms of stress, leading to improved overall mental health, reduced anxiety, and better mood regulation. Some studies have also shown that the practice can improve sleep patterns and aid in the management of symptoms associated with post-traumatic stress disorder (PTSD) and chronic fatigue syndrome.

Will an ice bath aid muscle recovery after lifting weights?

Ice baths are widely used among athletes for their ability to significantly reduce muscle soreness after intense physical activities, including weight lifting. The mechanism behind this involves the reduction of tissue temperature and constriction of blood vessels, which decreases metabolic activity and reduces inflammation around minor muscle injuries. This process helps in flushing out the lactic acid buildup in muscles that can occur after lifting weights, according to a study in the Journal of Physiology.

The cold can also help reduce swelling and tissue breakdown: when the body rewarms, the increased blood flow helps to return the byproducts of muscle breakdown to the liver, where they can be converted into less harmful substances, thereby speeding up muscle recovery and shortening the time needed for recovery.

Will an ice bath aid recovery after cardiovascular exercise?

Similar to recovery from weight lifting, ice baths can aid in the recovery process after cardiovascular exercises by reducing inflammation and speeding up the removal of lactic acid.

For endurance athletes, such as marathon runners or cyclists, cold water immersion helps to alleviate the immediate soreness and stiffness associated with long durations of aerobic activity, such as Zone 2 cardio. This not only hastens the recovery process but also minimises the delayed onset muscle soreness (DOMS) that typically follows strenuous endurance workouts.

An ice bath can also effectively reduce heart rate and core temperature post-exercise, facilitating quicker bodily recovery and allowing athletes to maintain a higher level of performance in subsequent workouts, according to a study from The American Journal of Sports Medicine.

What are the long-term physical health benefits of an ice bath?

Engaging in regular cold water immersion can offer several long-term physical health benefits, including: enhanced immune system function; improved cardiovascular health; and increased metabolic rate function.

Regular cold exposure can also stimulate the production of white blood cells and antioxidant pathways, enhancing the body’s defence mechanism against infections and disease, and as the body works to heat itself, cardiovascular circulation improves, potentially reducing the risk of heart disease.

There is also evidence suggesting that cold exposure can increase brown fat activity, which helps in burning calories, reducing body fat levels, and improving glucose metabolism, thereby aiding in the management of type-2 diabetes.

Do ice baths improve heart health?

Cold water immersion has a profound effect on the cardiovascular system. Initially, the shock of the cold constricts blood vessels, reducing blood flow to extremities and increasing blood pressure. This response also diverts blood to the core to protect vital organs, enhancing central circulation. Over time, with regular immersion, the cardiovascular system becomes more efficient at redistributing blood throughout the body, which can improve overall heart health and endurance.

Regular exposure to cold water has been linked to a decreased heart rate and increased stroke volume, which are indicators of an efficient heart. A study in Circulation journal found that repeated cold immersion significantly reduced the risk of cardiovascular diseases by improving arterial health.

Can an ice bath combat chronic pain or inflammation?

Cold therapy is beneficial for managing chronic pain and inflammatory conditions, such as rheumatoid arthritis and fibromyalgia. The cold helps numb nerve endings, providing immediate pain relief, and the reduction in body temperature can decrease inflammation and slow the rate of biochemical reactions, which typically exacerbate inflammatory conditions.

Regular ice baths can lead to adaptations that lower the baseline level of inflammation in the body. Hydrotherapy, including cold water immersion, can significantly reduce pain and improve quality of life for patients with chronic inflammatory diseases, according to research in the Clinical Rheumatology journal.

What health risks are associated with ice baths?

While an ice bath offers numerous benefits, they also come with potential risks if not conducted properly.

The primary risks include hypothermia – where the body’s core temperature drops to dangerously low levels – and frostbite, which can occur if skin is exposed to cold temperatures for too long. To minimise these risks, it’s essential to limit the duration of ice baths to no more than 15 minutes, especially for beginners or those without previous exposure to cold therapy.

It’s also crucial to enter the water gradually to allow the body to adjust to the shock of the cold, and to ensure that the water temperature is not excessively cold – ideally never lower than 10°C (50°F).

Who should avoid ice baths?

Cold water immersion is not suitable for everyone and people with certain health conditions should avoid this practice, especially those with cardiovascular diseases such as heart failure, arrhythmias, or those who have suffered a heart attack, due to the significant stress cold exposure places on the heart.

People with hypertension should also exercise caution, as cold immersion can cause a spike in blood pressure. Pregnant women and those with compromised immune systems may be advised to avoid cold therapies to prevent potential health risks. It’s always recommended that anyone considering cold water immersion to first consult with a medical professional to assess their suitability for this kind of therapy.

Do men and women have different physiological response to ice baths?

It’s a great question. Yes. On-going research is shining a spotlight on some significant gender differences in physiological responses to ice baths and cold exposure.

Women often report feeling colder quicker than men, which could be due to differences in body composition, such as a higher fat-to-muscle ratio, affecting heat loss and insulation. Hormonal fluctuations also play a role, with each phase of the menstrual cycle differently influencing body temperature regulation.

Despite these differences, both men and women can benefit significantly from cold water immersion when done correctly. However, individual responses can vary widely, and as such, personal experiences should guide the frequency and duration of ice bath therapy to optimise benefits while minimising discomfort and risk.