What Is an Infrared Sauna and How Does It Work?

Rather than mainly heating the air, an infrared sauna uses infrared heating elements that transfer warmth to your body and to the surfaces in the room. That is why the air temperature can be lower while your body still becomes gradually warm.

For many people this makes for a gentler and more approachable sauna experience – especially if the intense air of a traditional sauna feels a little too hot.

What is an infrared sauna?

IR is short for infrared radiation. It is a form of electromagnetic radiation that lies outside the part of the light spectrum our eyes can see, but which we can experience as warmth.

Infrared radiation occurs naturally around us, for instance in the warmth of the sun and of a fire. It is not the same thing as ultraviolet radiation, UV, which is present in sunlight and in sunbeds. Infrared and ultraviolet light sit in different parts of the electromagnetic spectrum.

In an infrared sauna, the heating elements convert electrical energy into infrared heat radiation. When that radiation is absorbed by the skin and other surfaces, the energy turns into warmth.

How does an infrared sauna work?

In a traditional sauna it is above all the air that is heated by the stove. The hot air and the warmed surfaces then transfer the heat to your body.

An infrared sauna instead uses heating elements that emit infrared radiation. The air in the cabin becomes warm too, but it usually does not need to reach the same temperature as in a traditional sauna for the body to feel distinctly warm.

Many infrared saunas are used at temperatures of around 45–60 degrees Celsius. The exact temperature varies with the construction of the cabin, the settings and how long it has been heating.

The warmth is often experienced as more even, drier and less intense in the air. That can make it more comfortable to stay seated for a longer, calmer while. Mayo Clinic also describes the lower temperature as one reason some people prefer an infrared sauna to a traditional one.

At the same time, the experience is individual. Some people start to perspire fairly quickly, while others need longer before the body feels properly warm.

What happens in the body when it gets warm?

When the body is exposed to heat, it works to keep its core temperature at a stable level.

The blood vessels near the surface of the skin widen and more blood is directed towards the skin. At the same time the sweat glands are activated. As sweat evaporates from the skin, it helps the body get rid of excess heat. Your pulse may also rise while the body works on regulating its temperature.

These natural responses lie behind much of the sauna experience. The skin becomes warm, perspiration increases and after a while the body can feel softer, heavier or more relaxed.

One study comparing an infrared sauna with moderate physical activity found that the responses during the sauna session could mainly be explained by the body’s temperature regulation. An infrared sauna should therefore not be seen as a replacement for exercise or everyday movement.

How does an infrared sauna differ from a traditional one?

The clearest difference is in how the warmth is created and how it feels.

That does not mean one form of sauna is better than the other. They simply offer different kinds of experience.

Does an infrared sauna warm the body from within?

Infrared saunas are sometimes described as “warming the body from within”, or as if the heat travelled very deep into the body. That is a simplified description that can easily become misleading.

How far infrared radiation is absorbed depends on the wavelength used. Some infrared wavelengths are absorbed mainly at the surface, while others can reach a few millimetres further into the skin and the adjacent tissue. Once warmth has formed, it can then spread further through the tissue and the blood circulation.

In a 2025 study, muscle temperature rose during a far-infrared sauna session. The increase was smaller the deeper it was measured, however, and was negligible at greater depths.

A more accurate description is therefore that the heat radiation of an infrared sauna is absorbed by the skin and nearby tissue, after which the warmth gradually spreads further through the body.

How can a session feel?

When you sit down in the cabin, the temperature often feels pleasant and relatively mild. The warmth then builds up gradually.

After a while the skin can feel warmer and perspiration begins to increase. How quickly this happens depends on things such as the temperature, where you sit in relation to the heating elements, your own heat tolerance and how used to sauna bathing you are.

Common experiences during or after a session include:

• a sense of relaxation
• softness and warmth in the body
• noticeable perspiration
• a calmer pace
• a pleasant feeling of winding down
• a while where everyday impressions feel further away

These are personal experiences and should not be seen as guaranteed medical effects. For many people the value lies above all in the moment itself: closing the door on the world outside, feeling the warmth build and being undisturbed for a while.

What does research say about infrared saunas?

Research into sauna bathing and other forms of passive heat has examined possible links with blood pressure, cardiovascular health, pain, recovery and wellbeing, among other things.

It is important, however, to distinguish between research on traditional Finnish saunas and research specifically on infrared saunas. The most extensive and long-term research concerns traditional saunas, and the results cannot automatically be transferred to infrared saunas.

A comparative study from 2025, for example, showed that a far-infrared sauna produced a smaller rise in core body temperature and weaker immediate physiological responses than a traditional sauna and hot water immersion.

There are smaller studies in which infrared saunas have been examined in relation to various conditions and complaints. Some results are interesting, but the studies are often small, short-term or carried out in specific patient groups.

Mayo Clinic summarises the evidence by noting that some studies have shown possible benefits, but that larger and more rigorous studies are needed before firm conclusions can be drawn.

The most responsible view is therefore to see an infrared sauna as a form of warmth, relaxation and wellbeing – not as a treatment or a cure for illness.

Is an infrared sauna the same as red light therapy?

No. An infrared sauna and red light therapy are two different things, even though the technologies can use wavelengths within or close to the infrared range.

In an infrared sauna the main purpose is to create warmth in the body and the room. Red light therapy, sometimes called photobiomodulation, uses specifically selected wavelengths, light doses and distances for other purposes.

Research findings on red or near-infrared therapeutic light can therefore not be used as evidence that an infrared sauna produces the same effects.

Research on infrared saunas and the skin is still limited. There is not enough evidence to say that an ordinary infrared sauna builds collagen, rejuvenates the skin or treats skin conditions.

The warmth can, however, temporarily leave the skin warm and rosy, which some people experience as a fresher glow afterwards.

Do you sweat out toxins in an infrared sauna?

Perspiration is above all the body’s way of regulating its temperature.

Sweat consists mainly of water and salts. Smaller amounts of other substances may also be present, but the sweat glands are not the body’s main system for breaking down and removing waste products. That central role belongs to the liver, the kidneys and the gastrointestinal tract, among others.

An infrared sauna should therefore not be described as a detox or as a way of cleansing the body of toxins.

It is more accurate to say that the warmth makes the body perspire as a natural part of temperature regulation.

Your first time in an infrared sauna

There is no reason to push your body during the first session. Start at a calm pace and give yourself time to notice how you feel.

Drink water

When you perspire, your body loses fluid. Drink water as usual before your visit and top up afterwards.

Anyone who has been given specific advice about fluid intake because of heart or kidney disease, for example, should follow the guidance of their healthcare provider.

Avoid a very heavy meal beforehand

Many people find it more comfortable to use a sauna after a light or normal meal than immediately after eating a great deal.

Listen to your body

Leave the cabin if you feel dizzy, nauseous, unusually weak or confused, or if you develop a severe headache or palpitations. Such symptoms can be a sign that the heat or the loss of fluid is affecting your body too much.

Avoid alcohol

Alcohol can affect both judgement and the body’s fluid balance and should not be combined with sauna bathing. The Swedish healthcare guide 1177 recommends avoiding alcohol and paying attention to fluid intake in strong heat.

Who should take extra care?

An infrared sauna is not suitable for everyone or for every situation.

Seek advice from a healthcare professional before sauna bathing if you are pregnant, have cardiovascular disease, kidney disease, very low or unstable blood pressure, or a condition that affects the body’s temperature regulation.

The same applies if you have a reduced ability to sense heat or take medication that can affect blood pressure, perspiration or the body’s fluid balance.

Older people and people with certain conditions can be more sensitive to heat and fluid loss. According to 1177, some medicines can also affect fluid balance.

A calm moment – not a performance

Even recovery can easily turn into something to be measured: the highest temperature, the longest time or the most sweat.

But an infrared sauna does not have to be about performing.

The temperature and the amount of perspiration do not determine how successful the experience is. A shorter, comfortable while can be more rewarding than staying until the body feels tired or overheated.

For many people the value lies in something far simpler: being able to close the door, letting the warmth build at its own pace and giving yourself a while without outside demands.

Frequently asked questions about infrared saunas

Experience an infrared sauna at Solportalen in Uppsala

At Solportalen you can experience infrared warmth in a calm and private setting in central Uppsala.

Here the moment does not have to be about enduring the highest possible temperature. You can let the warmth build gradually, disconnect from the world outside and settle into a while of stillness and recovery.