Saunas and light therapy—or photobiomodulation (PBM), as it’s technically called—are becoming popular options for those seeking wellness, and there’s an overwhelming amount of information available on each. Unfortunately, much of this information is confusing, not based on science, or just plain incorrect. Both therapies offer proven benefits—but there are some key differences to understand.

This article will clear up some common misconceptions and provide clarity around the critical differences between saunas and PBM, helping you along your wellness journey.

The History of Saunas

What we now call a sauna originated hundreds of years ago in Finland, and remains a strong feature of the Finnish culture to this day. In fact, almost every home in Finland includes a built-in sauna. They are found everywhere: from country cottages to city apartments. Even the President has a private sauna—and so do most citizens!

The oldest saunas contained a fireplace with large stones and were typically dug into the slope of a hill, along with the rest of the home. When water was splashed onto these heated stones, the steam rising off them warmed the room so well that people inside could remove all their clothing—even in the dead of winter! Although the technologies have advanced, saunas are still viewed as a necessity and often used for both sanitation and health. Common practices include stimulating the skin with birch twigs and leaves and cooling off by jumping into nearby snow, water, or a cold shower. The Finns shared their sauna practices with surrounding countries in Europe, and eventually, it spread to North America.[1]

Modern convection-type saunas made popular by the Finns deliver heat by warming the air inside the sauna. In recent decades, infrared saunas have become popular. Instead of warming the air, they actually heat objects inside the space. Infrared saunas use charcoal, carbon fiber, or other types of emitting surfaces to deliver infrared heat. While many saunas are marketed as providing “full spectrum” infrared wavelengths, the vast majority of research supporting the health benefits of saunas is tied directly to the temperature, humidity, and treatment time under which your body is exposed to heat. The most effective wavelengths, in terms of generating heat, are in the far infrared spectrum. We’ll cover this in more detail below—but in short, the purpose of all saunas is to deliver heat in sufficient amounts to raise your body’s core temperature.

How Do Saunas Benefit the Body?

All saunas work by inducing thermal stress on the body—but what, exactly, does this accomplish?

There are several biological responses, which include increased heart rate and perspiration. Also, a sufficient amount of heat affects the body’s protein metabolism process—essential in all living things. A special kind of protein—technically referred to as heat shock proteins—actually respond only to cellular stress caused by heat. So, by inducing heat stress on the body, these special proteins become activated—which leads to some interesting health benefits very similar to those gained through physical exercise.

For example, participants in one study sat for a 30-minute sauna treatment (at a humid 194℉) after 13 work sessions over the course of 3 weeks. At the end of the study, these participants experienced an increase of 32% in performance tests compared with those who didn’t use the sauna![2]

While the majority of benefits from saunas are related to increased cardiovascular function, other studies have demonstrated benefits like improvement in chronic fatigue, decreased depression, and helping your body clear toxins.[3] As you can see, saunas have some pretty amazing health benefits!

How Do Saunas Compare to Light Therapy?

The benefits of light therapy—or PBM—relate to how light energy impacts the body at the cellular level. Specific wavelengths of light have some amazing effects on the mitochondria in our cells, which are sometimes called the “engine” of the cell. Instead of using heat to induce a cardiovascular stress on your body—the way saunas do—PBM literally feeds energy into our cells with photons from light, similar to natural sunlight.

When looking at the entire light spectrum delivered by the sun, a vast majority of wavelengths, including ultraviolet (UV), are absorbed very quickly by the outer layers of the skin tissue—and felt as heat. This is why we feel warmth from sunlight, and from other sources like fire and hot coals.

But there is a narrow band of wavelengths that can penetrate human tissue much more effectively, and scientists have discovered that some of these wavelengths have a unique ability to boost cellular function and energy. A simple way to think of this process is that the photons in these wavelengths essentially charge your “cellular batteries.”

The improvements in cellular function generated by these wavelengths—at about 630-670 nm and 830-850 nm—have been shown to provide a wide range of benefits, including improved skin health, enhanced muscle recovery, reduced joint pain, increased fertility, and even weight loss![4,5,6,7,8] Just like saunas, light therapy—or PBM—has some pretty amazing physiological benefits too!

What You Should Look for in Saunas and Light Therapy Devices

In order to see benefits from a sauna, it needs to reach a certain temperature. Therefore, look for convection saunas that can sustain air temperatures between 170-200℉, the range cited in most published clinical literature. Alternatively, with infrared saunas, make sure to select one that provides an equal amount of heat using high-quality carbon emitters. Remember, saunas should provide heat as a form of therapy, so it’s important to understand the differences required for health benefits. Beyond that, be wary of additional unsubstantiated claims.

Light therapy works much differently. It boosts cellular function by restoring electrochemical pathways, enabling mitochondria to produce more cellular energy. But just like saunas, light therapy devices aren’t created equal. In our definitive guide to choosing a light therapy device, we cover this in great detail. But in short, look for a device that can deliver the right wavelengths and effective irradiance (intensity) over a large treatment area. These factors will make all the difference in the world.

But What About Near Infrared Saunas?

Technically, a near infrared sauna is almost a contradiction of terms since near infrared wavelengths produce very little heat. And remember, the primary goal of sauna therapy is to generate a heat response in your body. High-quality saunas (like Clearlight, for example) utilize far infrared, or IR-C, wavelengths that are much more effective at delivering heat, as shown in the graph below:

Wavelengths that Work Best for Saunas

Light Therapy and Saunas—Friends, with Benefits!

Saunas and light therapy are two clinically-proven therapies that offer amazing benefits. Because saunas deliver energy in different forms and wavelengths, there is no effective overlap between the two therapies. They actually compliment each other quite well! Therefore, as you continue your personal wellness journey, consider adding both light and sauna therapy to safely and naturally enhance your overall health.