Red Light Therapy vs Infrared Sauna: The Difference

I was at a friend's hytte a few weekends back, the kind with a proper wood fired sauna tucked into the corner of the hytte, and after about ten minutes of sitting in there sweating like I'd run somewhere, someone said, "isn't this basically what your red panels do?" And I get it. Both involve sitting near something glowing, both make you feel good afterwards, both get filed under "recovery" in most people's heads. But no. Not even close. And the mix up matters, because if you're using one expecting the results of the other, you'll end up disappointed by something that's actually working perfectly well, just not for the thing you thought it was doing.

On a personal note, I use both, and there are certain circumstances where I use them close together in time, but that's a topic for a different post.

Red light therapy and infrared saunas are both useful, but they work through almost entirely different mechanisms. Red light therapy uses specific red and near-infrared wavelengths, roughly 630 to 850nm (and up to around 1100nm in some devices), delivered at low power to trigger a response inside your cells, mainly in the mitochondria, without meaningfully raising your body temperature. Infrared saunas work by heating your body directly, raising your core temperature by a degree or two over 20 to 40 minutes, and the benefits come largely from that heat stress itself, the sweating, the cardiovascular load, the relaxation response. One is a light signal. The other is a heat workout. Both have research behind them, and both involve the electromagnetic spectrum, but they are not interchangeable.

What's actually different at the cellular level

Here's the bit that gets lost in all the marketing. Red and near-infrared light at the wavelengths used in photobiomodulation get absorbed by specific enzymes in your mitochondria called cytochrome c oxidase. A 2018 review by Hamblin lays this out in detail, the light helps free up the electron transport chain inside the cell, which can increase ATP production and reduce some markers of oxidative stress. You can read it here: https://pmc.ncbi.nlm.nih.gov/articles/PMC5844808/. This happens at low light intensities, with barely any heat involved. You could, in theory, sit under a red light panel for twenty minutes and your skin temperature would barely register it.

An infrared sauna is a completely different conversation. Far infrared wavelengths, much longer than the ones used in red light panels, get absorbed mostly as heat. Your core temperature climbs, your heart rate goes up, you sweat. The benefits being researched here are things like heat shock protein production, cardiovascular conditioning, and the kind of relaxation response you get from any sustained heat exposure. It's a stress response, a good one, similar in some ways to what moderate exercise does, just without moving.

So when someone asks "isn't it the same thing", the straight answer is that they're both using light-adjacent technology to do something useful to your body, but one is a chemical signal to your cells and the other is a thermal workout. Different tools, different toolbox slots.

The sauna research is real, but read the fine print

I want to be careful here, because this is exactly the kind of thing where I get a bit sceptical of my own industry. The most cited research on sauna and cardiovascular health comes from Finland, a large prospective study following over two thousand middle aged men, where frequent sauna bathing (four to seven sessions a week) was linked to a meaningfully lower risk of fatal cardiovascular events compared to occasional use. You can read that one here: https://pubmed.ncbi.nlm.nih.gov/25705824/.

Here's the thing though. That study was on traditional Finnish saunas, the kind heated to 80 to 100 degrees Celsius with low humidity, often wood fired, the sort of sauna that's been part of Nordic life for centuries. A lot of infrared sauna marketing borrows this research wholesale, even though infrared cabins typically run at much lower air temperatures, 45 to 60 degrees, and work through a different heating mechanism entirely. I personally choose traditional heaters where possible, for exactly this reason. That doesn't mean infrared saunas don't do anything, there's a reasonable case that the core temperature rise and the sweating response share some of the same pathways. But the strongest cardiovascular evidence we have is for the traditional hot, dry, high temperature sauna, not specifically the infrared cabin sitting at a much gentler heat. If a brand is showing you that Finnish cardiovascular study to sell you an infrared cabin, that's a bit of a stretch, and it's worth knowing.

So which one were you actually after?

This is the question I'd ask anyone trying to decide between the two, or wondering whether they need both. If what you're after is the feeling of being thoroughly warmed through, sweating properly, the kind of deep relaxation that comes after a proper heat session, plus the cardiovascular conditioning that comes with doing that regularly, that's the sauna lane. If what you're after is something you can do daily, sit in front of for ten to twenty minutes without breaking a sweat, aimed at joint pain, skin, muscle recovery, or just generally supporting your mitochondria through a Norwegian winter when sunlight is scarce, that's the red light lane.

So go on, which of those two were you actually picturing when you searched for this? Because they're two pretty different evenings.

Why this matters even more in Norway

Here's the bit that's quite specific to where we live. An enormous number of Norwegian homes and hytte already have a sauna. I have a few friends with different variations, wood fired, electric, barrel saunas out in the garden. That's wonderful, there's a good reason it's been part of life here for so long. But it means a lot of people in Norway already think of "warm box that makes you feel good" as a solved problem, and assume a red light panel is just a fancier, more expensive version of the same thing.

It isn't. Your sauna is doing very little for your mitochondria's cytochrome c oxidase, and your red light panel isn't going to make you sweat in any meaningful way (there are exceptions, I've occasionally noticed a mild warmth after a longer session, but nothing close to a sauna) or give you the cardiovascular workout a proper sauna session does. If you've got access to both, and a lot of people here do without realising it, they complement each other rather nicely. Sauna for the heat and cardiovascular side, red light for the cellular and recovery side. Just don't expect one to do the other's job.

How I'd think about combining them

If you've got both available, most of the practical guidance suggests doing them at different times rather than stacking them in the same session, since you're asking your body to do two quite different things. Those red light panels you sometimes see marketed for use inside a sauna cabin? At present I haven't found any mechanism or research that suggests that's beneficial, and the heat inside a sauna may actually work against some of what the light is trying to do at the cellular level.

Some people do red light in the morning as part of a routine and save the sauna for evening winding down. Others do it the other way round. There isn't a single right answer, and if anyone tells you there is, I'd be a little sceptical. My own approach, when doing them close together, is red light before a workout and sauna after. Red light beforehand can also help mobilise fat stores and may help dilate blood vessels before the heat stress of the sauna, so there's a reasonable case for that order if you're doing them in the same session.

What I would say is don't buy a red light panel expecting it to replace your sauna, and don't assume your sauna is doing what a red light panel does for joint pain or skin. If you want to read more about how red light fits into a Norwegian winter routine specifically, I wrote about that here: red light therapy as your mitochondrial heater for Norwegian winter. And if dosing is something you're unsure about, this connects directly to the biphasic dose idea I keep coming back to, more isn't always better, and I wrote about that here: why the right dose of red light therapy matters.

If you want to look at the panels I've tested, the red light panels collection has the specs and irradiance data for each one. And if you're trying to work out what actually makes sense for your situation, sauna, panel, or both, message me, that's what I'm here for.

Disclaimer: This post is for educational purposes and does not constitute medical advice. Both red light therapy and sauna use can affect blood pressure, heart rate and circulation. If you have a cardiovascular condition, are pregnant, or have any chronic health condition, speak with your doctor before starting either.

Frequently Asked Questions

Is an infrared sauna the same as red light therapy?

No. Infrared saunas work mainly by raising your core body temperature using longer infrared wavelengths, producing sweating and a heat stress response. Red light therapy uses much shorter red and near-infrared wavelengths at low power to trigger a cellular response, mainly in the mitochondria, without significantly raising body temperature. They're both light-related technologies but work through different mechanisms.

Can I use red light therapy and an infrared sauna on the same day?

Generally yes, most people use them at different times of day rather than in the same session, since they ask your body to do different things. There's no strong evidence that combining them in one sitting is harmful, but there's also no clear evidence it's better than doing them separately.

Which is better for muscle recovery, red light or infrared sauna?

Both have research suggesting benefits for recovery, but through different routes, red light therapy through its effect on mitochondrial energy production and inflammation, sauna through increased blood flow, heat shock proteins and relaxation. Many people use both, just not necessarily for the same purpose or in the same session.

Does an infrared sauna give the same skin benefits as red light therapy?

Not in the same way. Red light therapy's skin benefits are linked to specific red wavelengths interacting with skin cells at a cellular level. Sauna related skin benefits are mostly attributed to increased circulation and sweating, which is a different mechanism, useful in its own right, but not a substitute for the wavelength-specific effects of red light.

Er infrarød sauna det samme som rødlysterapi?

Nei. Infrarød sauna virker hovedsakelig ved å heve kroppstemperaturen din ved hjelp av lengre infrarøde bølgelengder, noe som gir svetting og en varmestressrespons. Rødlysterapi bruker mye kortere røde og nær-infrarøde bølgelengder ved lav styrke for å utløse en cellulær respons, hovedsakelig i mitokondriene, uten å heve kroppstemperaturen nevneverdig. Begge er lysrelaterte teknologier, men de virker gjennom forskjellige mekanismer.

References

Hamblin MR. Mechanisms and mitochondrial redox signaling in photobiomodulation. Photochemistry and Photobiology. 2018. https://pmc.ncbi.nlm.nih.gov/articles/PMC5844808/

Laukkanen T, Khan H, Zaccardi F, Laukkanen JA. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Internal Medicine. 2015. https://pubmed.ncbi.nlm.nih.gov/25705824/

Zhao J, Tian Y, Nie J, Xu J, Liu D. Red light and the sleep quality and endurance performance of Chinese female basketball players. Journal of Athletic Training. 2012. https://pubmed.ncbi.nlm.nih.gov/23182016/