The Science of Sauna, Cold & Contrast Therapy

A tradition backed by growing research

Across Finland, Germany and much of Northern Europe, people have long combined heat, cold and rest as part of everyday life. While these traditions began centuries ago, modern research is increasingly helping us understand how they may support health and wellbeing.

Sauna, cold water immersion and contrast therapy each affect the body in different ways. Used together, they create a balanced practice that many people find both restorative and enjoyable.


At a glance

Current research suggests that regular sauna use may:
 

• Support cardiovascular health

• Improve circulation

• Promote relaxation and reduce stress

• Help muscles relax and recover

• Support better sleep

 
Research suggests that cold water immersion may:
 

• Reduce muscle soreness after intense exercise

• Improve mood and wellbeing

• Reduce feelings of stress

• Increase alertness

• Complement the benefits of sauna

 

The benefits of sauna

Some of the strongest evidence comes from Finland, where researchers followed more than 2,300 middle-aged adults over 20 years.
 
Compared with people using a sauna once a week, those using one four to seven times each week had:
 

• 40% lower observed risk of death from all causes

• 50% lower observed risk of fatal cardiovascular disease

• 63% lower observed risk of sudden cardiac death

 
Although these studies show an association rather than proving cause and effect, the findings remained strong after accounting for factors such as age, smoking and physical activity.

During a sauna session, your heart rate increases, blood vessels widen and circulation improves in a similar way to moderate physical exercise. Many people also find that sauna helps them relax, sleep more deeply and recover after physical activity.
 
 
The benefits of cold water

Cold water immersion creates an immediate response. Breathing becomes faster, heart rate increases and the body works to conserve heat.

As breathing settles, many people report feeling calmer, clearer and more focused.

The strongest evidence for cold water immersion relates to recovery after exercise. Studies consistently show that it can reduce perceived muscle soreness during the 24 to 48 hours following intense exercise.

Emerging research also suggests cold water immersion may reduce feelings of stress, improve wellbeing and support better sleep, although further high-quality research is still needed.

 

Cold water and women

Much of the research on cold water immersion has historically been conducted in men, meaning scientists are still learning how women may respond differently. Hormonal changes throughout the menstrual cycle, as well as life stages such as perimenopause and menopause, can influence body temperature regulation and the way cold is experienced. Experts in women's physiology, including Dr Stacy Sims, suggest that women may benefit more from shorter, less intense cold exposure, with the emphasis on feeling refreshed rather than enduring extreme temperatures. As with sauna, the most important approach is to listen to your body and adapt your experience to how you feel on the day.

Why combine heat and cold?

Across Northern Europe, cooling down has always been considered an important part of the sauna experience.
Alternating between heat and cold challenges the body in different ways. Heat increases circulation and promotes relaxation, while cold activates the body's natural stress response before encouraging recovery as breathing slows and the body adapts.
Many people find that alternating between sauna, cooling down and rest leaves them feeling refreshed, clear-headed and restored.
 

What the evidence doesn't support

Although research into sauna and cold water immersion continues to grow, some popular claims are not supported by current evidence.
Research does not show that sauna or cold plunges:
 

• Flush toxins from the body

• Produce significant fat loss

• Cure illness

• Replace regular exercise

• Dramatically strengthen the immune system

 
The strongest evidence currently supports the benefits of sauna for cardiovascular health and the use of cold water immersion for reducing muscle soreness after exercise.
 
 
Enjoy sauna and cold water safely
 
For most healthy adults, sauna and cold water immersion can be enjoyed safely.
 
Listen to your body, stay hydrated and leave the sauna or cold water immediately if you feel unwell.
 
Sauna and cold water immersion are not recommended during pregnancy. If you have a medical condition or are unsure whether these experiences are suitable for you, please seek medical advice before visiting.
 
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