A 20-Year Study With 2,315 People Changed What We Know About Saunas — And The Result Surprised Researchers

20% less cardiovascular risk. Better sleep. Less joint pain. And a simple ritual, done at home, which is now back at the centre of the conversation about longevity.

From the age of 30, something begins to happen almost invisibly to the body: the loss of daily resilience. A small effort costs more. Rest is no longer as restorative. Stress accumulates more easily. And what once seemed natural — recovering well, sleeping soundly, and maintaining stable energy — now requires more attention.

For a long time, the idea of using heat as a health tool was associated only with spas, hotels, or specific cultural habits. But in recent years, a new generation of studies has brought saunas back into the discussion about recovery, longevity, and prevention.

Among these, a study involving 2,315 participants, followed for two decades, stands out, helping to change how many researchers view regular heat exposure.

What the 20-year study says

In 2015, a widely cited study followed 2,315 adult men for about 20 years, seeking to understand if there was a relationship between the frequency of sauna use and various long-term health indicators.

The results were consistent: participants who used saunas more regularly showed better overall health indicators compared to less frequent groups.

More than an isolated result, this study helped consolidate an idea that physiology had already been suggesting: when used consistently, heat can act as a positive stimulus for the body.

The most interesting thing is that the benefits do not seem to depend on extreme routines. In many cases, regular sessions of moderate duration are enough to produce relevant adaptations over time.

In other words: sauna doesn't have to be a luxury. It can be a routine tool.

The effect on sleep most people don't expect

Those who use a sauna for the first time tend to think mostly about immediate relaxation. But one of the most valued effects by those who maintain this habit is the quality of sleep in the following hours.

When the body is exposed to heat and then gradually returns to its baseline temperature, a response is triggered that promotes deep relaxation. In many people, this translates into reduced muscle tension, calmer breathing, and easier falling asleep.

For those living under constant stress, this can be one of the most underestimated advantages of a sauna: not just the comfort of the moment, but the indirect impact on nocturnal recovery and the feeling of rest the next day.

Muscles, joints and chronic pain

Another point frequently associated with regular heat use is the relief of muscle and joint stiffness. The feeling of "body locked up", very common after training, long periods of sitting, or phases of accumulated tension, tends to decrease with controlled thermal exposure.

Heat improves the sense of mobility, helps relax tense tissues, and can make recovery more comfortable — especially for those who combine frequent workouts with sedentary work or high levels of daily stress.

This is also why saunas are increasingly seen as a simple complement to recovery, well-being, and self-care routines. Not as a substitute for medical treatment, but as real support for the sensation of a functional body in daily life.

The angle no one expected: heat and metabolism

A sauna session represents a controlled physiological effort for the body. Heart rate increases, circulation is stimulated, and there is a higher energy expenditure than during absolute rest. This is why some people describe sauna as a form of “active rest”.

This is not to replace exercise, of course. But this type of response helps explain why heat has been analyzed not only for the feeling of comfort but also for the systemic effect it can trigger when integrated into a consistent routine.

The most interesting thing is that the benefit seems to result from the combination of moderate thermal stress, subsequent relaxation, and repetition over time. In other words: the body adapts — and this adaptation can impact how it recovers, regulates tension, and responds to effort.

How much does it cost to access these benefits?

A traditional fixed-installation sauna can involve construction work, dedicated space, and a significant investment. For many people, this model is simply not compatible with the reality of their home.

In recent years, portable alternatives have emerged that allow heat to be integrated into the routine with much less friction: simple assembly, compact format, and use in domestic spaces. For those seeking consistency, this makes all the difference.

The big change is here: what once seemed reserved for hotels, spas, or clinics can now be incorporated much more practically into real life.

Portable saunas available on the Portuguese market

Alaska Recover has been popularising this format in the Portuguese market with portable models and systems designed for home use. The logic is simple: compact, affordable solutions geared towards a real recovery routine.

The most relevant models currently include simpler options, models with better insulation, and alternatives designed for those who want an experience closer to a traditional sauna.

All models include essential accessories and have been designed to fit into real home environments, without requiring a dedicated room or complex installation.

“I bought the sauna for the winter, but it was on the most stressful days that I noticed the biggest difference. It helps me unwind, sleep better and recover faster.”

— João M. - Aveiro, Portugal

“I didn't want a complicated solution or something fixed. The portable version was exactly what I needed to create a realistic ritual at home.”

— Susana P. - Setúbal, Portugal

“The direct effect wasn't just physical. After a few weeks, I started to feel less tense, lighter, and with a better ability to rest.”

— Carlos A. - Porto, Portugal