Taking a cold water bath, also known as cold hydrotherapy or cold water immersion, has become a popular health and wellness trend in recent years. Proponents claim that cold water bathing provides a long list of health benefits, including reducing inflammation, improving circulation, boosting metabolism, speeding up muscle recovery, and even alleviating depression. But how long should you sit in a cold tub to reap these rewards without causing harm?
What is cold water immersion?
Cold water immersion involves submerging the body in water that is 55-68°F (13-20°C). This is typically done in a bath tub, pool, lake or other body of cold water. The cold temperature causes vasoconstriction, which reduces blood flow to the extremities. When you get out of the cold water, vasodilation occurs as blood rushes back into your limbs. This constriction and dilation is thought to provide health benefits.
Some key points about cold water immersion:
- It causes a gasp response due to the sudden cold, activating the sympathetic nervous system.
- It initiates a stress response, releasing norepinephrine and cortisol.
- It burns calories as the body works to warm itself back up.
- It reduces inflammation as blood moves to the organs and away from the limbs.
While often used interchangeably, cold water immersion is not the same as cryotherapy, which involves exposing the body to extremely cold air (-166°F and below) for 2-4 minutes.
Benefits of cold water baths
Here are some of the evidence-based benefits of taking regular cold water baths:
1. Improves circulation
As mentioned, the cold causes vasoconstriction followed by vasodilation, which “pumps” blood through the vessels. This improved circulation delivers more oxygen and nutrients throughout the body while removing waste products.
2. Reduces inflammation
The cold temperature decreases inflammatory cytokines and markers of oxidative damage. This can provide relief from inflammation-related conditions like arthritis, muscle soreness, eczema and inflammatory bowel disease.
3. Boosts immunity
Frequent cold water immersion has been shown to increase levels of noradrenaline, dopamine and beta-endorphins, as well as decrease cortisol. These changes are associated with boosted immunity.
4. Burns calories
Your body has to work hard to warm itself back up following cold water immersion. This metabolic boost is associated with increased calorie and fat burning.
5. Speeds up muscle recovery
The cold may reduce muscle soreness and speed up recovery time following intense exercise. However, studies show inconsistent results so more research is still needed.
6. Elevates mood
Along with the hormonal changes, the refreshing feeling of being immersed in cold water and overcoming the initial shock may boost mood in some people. It also triggers the release of beta-endorphins.
7. Improves sleep
The changes in circulating noradrenaline and cortisol influence the sleep-wake cycle and taking a cold bath 1-2 hours before bed may help you fall asleep faster.
How cold should the water be?
For most healthy adults, the ideal temperature for cold water immersion is between 50-59°F (10-15°C). This is cold enough to cause the desired effect on blood circulation and metabolism, but not so cold as to be unbearable.
Some tips on managing the cold temperature:
- Start with warmer water (60-70°F) and gradually decrease the temperature over time.
- Only immerse yourself up to the neck/shoulders to avoid excessive stress on the body.
- Wear a hat to reduce heat loss through your head.
- Use ice packs instead of ice cubes to cool a warm bath and avoid direct skin contact with the ice.
How long should you stay in a cold bath?
Research indicates the ideal time to reap benefits from cold water immersion is generally 1-3 minutes per session. Here are some general recommendations based on your goal:
Improving circulation and reducing soreness:
Aim for 1-3 minutes in 50-59°F water.
Boosting alertness and focus:
30-90 seconds in 50-54° water.
Speeding up recovery after exercise:
5-15 minutes in 50-59°F water.
Burning calories:
30 minutes in 60-70°F water.
It is not recommended to stay in cold water for longer than 30 minutes at a time. Your body will eventually acclimate to the temperature, so you want to get out before reaching that point.
How often should you take a cold bath?
Most research on cold water immersion has involved frequent bathing, such as 4-5 times per week. However, even just 2-3 cold water baths per week appears to provide benefits.
There is no established limit for how often you can soak in cold water. As long as you are keeping the sessions brief, you can likely do it daily. But it is always wise to listen to your body and take a break if the cold immersion causes any negative symptoms or stops feeling invigorating.
Are there any risks of cold water baths?
Cold water immersion is considered safe for most healthy adults. But there are some potential risks to be aware of:
- Hypothermia – This is unlikely from short baths, but can occur if improperly cooled water is used or immersion is too long.
- Altered heart rhythms – The cold can trigger arrhythmias in susceptible individuals.
- Allergic reactions – Allergies to products added to bath water could occur.
- Frostbite – Extended exposure to extreme cold may freeze extremities.
- Aggravation of chronic conditions – Such as Raynaud’s disease, heart failure or respiratory disorders.
To stay safe, start slowly, monitor your body’s response, and consult your doctor if you have any chronic medical conditions or concerns.
Should you take a cold bath before or after exercise?
Studies show that cold water immersion may be beneficial both before and after exercise. Here are some general tips on timing:
Before exercise:
- Take a brief 30-90 second cold shower or immerse extremities.
- This activates the sympathetic nervous system and gets adrenaline going.
- Best for light activity like walking, tai chi, yoga, etc.
After exercise:
- Take a longer 5-15 minute cold bath.
- This reduces muscle soreness, inflammation and speeds recovery.
- Best after intense exercise like weightlifting, HIIT, running, etc.
Avoid extended cold exposure directly before intense or competitive athletic events as this can lower muscle temperature and power output.
Should you ease into the cold slowly or all at once?
There are arguments on both sides of this debate. Here are the potential pros and cons of each approach:
Slowly easing in:
- Allows your body more time to adjust to the decreasing temperature.
- Prevents shock from extreme cold which could be dangerous for some.
- May provide more cumulative exposure as you can stay in longer.
- Drawback is the prolonged discomfort as you lower yourself in slowly.
All at once:
- Provides an instant cold shock that is believed to activate positive stress pathways.
- Avoidance of gradual acclimation allows the cold to have a greater effect.
- Overcomes the worst discomfort immediately rather than dragging it out.
- Increased risk of longer term harm from sudden temperature changes.
For most people, quickly immersing yourself all at once is recommended. Just be sure to only stay in the cold water for a brief period of 1-3 minutes.
Should you take a warm or cold shower after a cold bath?
Taking a warm or hot shower after a cold water bath allows your body temperature to return to normal and prevents extended chilling.
You generally want to avoid a second cold exposure soon after the first. The exceptions would be alternating hot and cold (contrast hydrotherapy) or briefly plunging hands, feet or face into cold at the end.
Conclusion
While research on cold water immersion is still ongoing, the current evidence points to impressive benefits with minimal risk when done correctly. For most healthy adults, brief cold water baths of 1-3 minutes at 50-59°F, 2-4 times per week, is a simple therapeutic practice to boost circulation, immunity, mood and recovery.
As with any new health practice, consult your physician first if you have any medical conditions or concerns. Start slowly and pay close attention to your body’s response. With some discipline and an open mind, cold water immersion may provide a range of benefits to your overall health and wellbeing.
Frequently Asked Questions
What are the benefits of taking a cold bath?
Some of the evidence-based benefits of cold water immersion include improved circulation, reduced inflammation, boosted immunity, increased calorie burn, faster muscle recovery, elevated mood and better sleep quality.
Is it safe to take cold baths every day?
Yes, daily cold water bathing is generally safe as long as you limit the time immersed to 1-3 minutes and monitor your body’s response. Always consult a doctor first if you have any medical conditions.
Will a cold bath make me sick?
No, brief cold water immersion of 1-3 minutes should not make you sick. It may temporarily lower your body temperature but this will return to normal soon after getting out. The cold exposure actually activates your immune system.
Can cold water kill you?
Extremely cold water can lead to dangerous hypothermia and even death with prolonged exposure. However, typical cold bath temperatures of 50-59°F are safe for short durations of 1-3 minutes for most healthy adults.
How cold is too cold for a bath?
Water colder than 50°F starts to reach dangerous levels with prolonged exposure. For brief immersion, colder than 59°F can be uncomfortably cold. The ideal range is 50-59°F to reap benefits without excessive chilling.
Will cold showers build muscle?
No, cold water immersion alone will not build muscle. But it may help speed up recovery after strength training sessions, allowing you to work out harder and more frequently. This can indirectly help promote muscle growth over time.
Should you do cold showers before or after workout?
Pre-workout, a brief 30-90 second cold shower can get your adrenaline pumping. Post-workout, 5-15 minutes in cold water reduces inflammation and soreness to speed up recovery.
Can cold showers be harmful?
Cold showers are safe for most healthy adults. Potential harms include hypothermia, frostbite, arrhythmias and aggravating existing medical conditions. This is avoided by limiting time in cold water to 1-3 minutes. Consult a doctor if concerned.
Do cold baths burn fat?
Yes, studies show cold water exposure temporarily increases metabolism and fat burning. Regular cold baths may support weight and fat loss as part of an overall healthy diet and active lifestyle.
Can cold showers boost testosterone?
Brief cold showers may temporarily increase testosterone levels. But more research is needed to determine whether they can support sustained, long-term testosterone production. Warm showers may be better for testosterone.
