Infrared sauna: health effects & how often you should use one

Infrared saunas have more than 40 peer-reviewed studies behind them from 2020–2025. But unlike the traditional sauna, the effects are partly different – and the research points to specific health problems that infrared saunas address better than anything else.

There is a widespread misconception about infrared saunas: that they are simply a milder, more comfortable version of the traditional sauna. That is not the case. Infrared and traditional saunas activate partly different physiological mechanisms – and the research shows that infrared saunas have specific strengths a traditional sauna cannot match.

This article goes through what the research actually says about the health effects of infrared saunas, how often you should use one to see results – and why consistency is the only variable that really matters.

Want to compare with the traditional sauna and how often you should use that? Read our article How often you should use a sauna to see an effect, according to research

How an infrared sauna heats the body – and why that matters for the effect

Infrared saunas work in a fundamentally different way from traditional saunas. Instead of heating the air in the room to 80–100 °C, infrared panels emit radiation that penetrates 3–4 centimetres below the skin and heats muscle tissue directly – without the air temperature having to rise beyond 40–60 °C.

That property is what gives the infrared sauna its particular profile. At an air temperature of 50 °C the session is mild enough for you to sit for 30 minutes without feeling overwhelmed. At the same time the muscles are heated more deeply and more directly than in a traditional sauna. The sweating is different – more gradual and longer lasting.

The practical consequence: an infrared sauna is easier to use daily. That is one of the most important differences from a longevity perspective, because the strongest health effects in the research require frequent sessions.

Infrared saunas and mental health – the research that surprised the researchers themselves

The strongest and most unexpected finding in modern infrared sauna research concerns mental health. The results are strong enough that they have changed how leading psychiatrists think about treating depression and anxiety.

UCSF HEATBed Study 2024: a study at the University of California, San Francisco combined infrared heat therapy with cognitive behavioural therapy. The result: 86.2 % of participants diagnosed with major depression no longer met the criteria for the diagnosis after the treatment period. That is a figure few medicines can match.

Psychosomatic Medicine 2023 – cortisol: a randomised controlled trial with 156 participants over 8 weeks. The group using an infrared sauna three times a week for 30 minutes showed 24 % lower cortisol levels compared with the control group. Their score on the validated Perceived Stress Scale improved by 41 % – the control group improved by 15 %.

Psychiatry Research 2024 – endorphins: a single infrared sauna session increased endorphin levels by 210 % and serotonin levels by 18 % as measured in blood samples. The effect appeared after just one session.

The mechanism behind the mental health effects is probably a combination of endorphin release, reduced inflammation (strongly linked to depression), improved sleep quality and activation of the parasympathetic nervous system, which counteracts the chronic stress response.

Infrared saunas and cardiovascular health – what happens in the blood vessels

One of the strongest arguments for the infrared sauna as a longevity tool is its cardiovascular effects. A single 30-minute session produces cardiovascular responses comparable to a moderate cardio workout – the heart rate rises to 100–120 beats per minute, stroke volume increases and the blood vessels dilate.

Frontiers in Cardiovascular Medicine 2025: a systematic review of the sauna as a treatment method for cardiovascular health and peripheral artery disease highlighted heat therapy as a "novel management approach" – particularly for patients who cannot exercise for physical reasons. Infrared saunas were mentioned specifically for their advantages at lower temperatures.

Laukkanen & Kunutsor 2024: a broad review of passive heat therapy confirmed improved vascular function, reduced arterial stiffness, lower blood pressure and lower risk of cardiovascular disease, stroke and dementia with regular sauna bathing – including infrared.

The cardiovascular case for the infrared sauna is especially strong for one particular group: those who for various reasons cannot exercise. An infrared sauna provides exercise-like cardiovascular stimulus without the mechanical load on joints and muscles.

Infrared saunas and inflammation – CRP, rheumatic conditions and chronic pain

Inflammation is a common denominator behind most chronic illnesses – cardiovascular disease, diabetes, depression, autoimmune conditions and some cancers. It is also the area where infrared sauna research is most specific and most clinically relevant.

Reduction in CRP: studies show a 28–30 % reduction in C-reactive protein (CRP) – one of the most important markers of systemic inflammation – after 3 weeks of regular infrared sauna use. That is a clinically meaningful reduction.

Rheumatoid arthritis and ankylosing spondylitis: a study at Saxion University of Applied Sciences treated 34 patients (17 with rheumatoid arthritis, 17 with ankylosing spondylitis) with eight 30-minute infrared sauna sessions at 55 °C over 4 weeks. Patients reported a significant reduction in pain, stiffness and fatigue during the treatment period.

One important nuance: the research shows that anti-inflammatory effects take time. One or two sessions produce no measurable change in inflammatory markers. It is consistent, regular use over weeks that gives the measurable results – exactly as with exercise.

Infrared saunas and muscle recovery – a deeper effect at a lower temperature

This is the effect most people notice first: the body feels different afterwards. Muscles that were stiff are soft. Tension that sat there all day is gone. That is not placebo – it is physiology.

Infrared radiation penetrates 3–4 centimetres into muscle tissue and increases blood flow locally. That accelerates the removal of lactic acid and metabolic waste products from the muscle, reduces swelling and dampens the inflammatory response that causes delayed onset muscle soreness (DOMS).

Compared with a traditional sauna – which is also effective for recovery – the infrared sauna has the advantage of being available immediately. You do not have to wait 45–60 minutes for the cabin to warm up. You start it from the app, step in after 10–20 minutes and can take the session straight after training without having to reorganise the whole evening.

• DOMS is measurably reduced after even single sessions taken straight after training

• Blood flow increases locally in the treated muscle tissue thanks to IR penetration

• Sleep quality improves – deep sleep increases with regular infrared sauna use

• Cortisol falls – the stress hormone's baseline level drops by 24 % at 3x per week over 8 weeks

How often should you use an infrared sauna? A frequency guide based on research

The short answer: more is better, and consistency is everything. But here are the specific recommendations broken down by goal:

One important difference from the traditional sauna: the lower temperature of an infrared sauna makes daily use genuinely achievable for most healthy adults. You do not need to rest as long between sessions. That makes it easier to reach the frequency that delivers the strongest effects.

Building your infrared sauna routine – from beginner to optimal protocol

The most important advice is to start gently. Your body needs to get used to IR heat just as it does to any other training. Here is a gradual build-up:

Always listen to your body. Dizziness, nausea or extreme tiredness after a session are signals to lower the temperature or shorten the session. Drink water before and after.

Infrared or traditional sauna – do you have to choose?

It is the wrong question. The research shows clearly that they solve partly different problems.

The traditional sauna is superior for:

• Cardiovascular stimulus and longevity data (the KUOPIO study's 50 % lower cardiac mortality)

• The löyly experience and Nordic sauna culture

• Outdoor siting and contrast therapy with an ice bath

The infrared sauna is superior for:

• Mental health and depression treatment (86 % remission, UCSF 2024)

• Daily muscle recovery and pain relief

• Stress reduction and cortisol regulation

• Indoor installation and daily accessibility

The optimal solution is both. The Swedish Cold Hybrid Sauna combines a traditional 6 kW Harvia heater with full spectrum infrared heat in the same cabin – you choose the mode from the touch panel depending on what you need that day. One system. No compromises.

Read more about the Hybrid Sauna: Swedish Cold Hybrid Sauna – traditional and infrared in one

Scientific sources:

1. Mason et al., UCSF HEATBed Study (2024) – Infrared heat therapy and depression: 86.2 % of participants no longer met the criteria for major depression

2. Psychosomatic Medicine (2023) – Randomised controlled trial, 156 participants, 8 weeks: 24 % lower cortisol and 41 % improvement on the Perceived Stress Scale

3. Psychiatry Research (2024) – Single infrared sauna session: endorphins +210 %, serotonin +18 %

4. Zayed, M.A., Frontiers in Cardiovascular Medicine (2025) – The sauna as a treatment method for cardiovascular health and peripheral artery disease

5. Laukkanen & Kunutsor (2024) – Review of passive heat therapy: vascular function, arterial stiffness, blood pressure and dementia risk

6. Oosterveld et al., Saxion University – Infrared sauna in rheumatoid arthritis and ankylosing spondylitis: pain, stiffness and fatigue

7. Laukkanen et al., JAMA Internal Medicine (2015) – Traditional sauna bathing and cardiovascular mortality, 2,315 participants over 20 years