Sauna COVID Risk

In this blog post, I explore the topic of the sauna COVID risk you’re exposed to when spending time inside a sauna. I’ll also talk about whether a sauna can kill COVID when you’re infected - the science on this topic is actually quite surprising. But first, the basics:

COVID Basis: The Scientific Consensus

Fortunately, there’s a heap of science published continuously on the SARS-CoV-II virus and the illness it causes called “COVID-19”. I’ll just talk about COVID here for convenience as that’s the term most people are familiar with.

In the introduction I’ve written below, I’ve only used the latest publications from 2021-2022 (1; 2; 3; 4; 5). For that reason, all the knowledge below is up to date.

Due to the availability of many high-quality studies, many good predictors of COVID are available today. Age, being overweight or obese, many different pre-existing health conditions (such as heart disease, cancer, poor liver health, diabetes, and especially pre-existing lung conditions), are great predictors of COVID severity. Low vitamin D status and being of the male gender also increase risk.

COVID symptoms vary from person to person though. These symptoms include shortness of breath, pain on the chest, headaches, a fever, low blood oxygenation, loss of taste and smell, joint pain, fatigue, and others. In severe cases, COVID leads to hospitalisation, ICU admission, and even death. Mild cases also exist, of course, but these are of less importance for this blog post - because they can be asymptomatic and the problem mostly resolves itself.

Not everyone has it easy, however:

Up to one to six months after an infection, about 17% of people surviving COVID still have long-term health issues. Issues include lower functioning in everyday life and poorer quality of life. As a result, you might need rehabilitation.

All of these characteristics might change over time though, as the virus evolves genetically. Nevertheless, there are great indications saunas might play a major role in preventing COVID:

I’ve written about other airway health conditions in the past, such as pneumonia and asthma. In such cases, infrared saunas are generally a very good treatment for improving overall physical functioning and lowering the risk of developing long-term conditions of the airways. However, I’m only talking about preventive or rehabilitative, not treatment during the acute phase.

Nevertheless, the outcome in other lung and airway conditions such as asthma and pneumonia is very promising for COVID. It’s reasonable to expect that the long-term benefits of infrared sauna use also extend to COVID due to the overall reduction in mortality and improvement in health and well-being exists for respiratory diseases across the board.

This outcome is especially promising as infrared saunas lower the risk of having lung conditions and also lower the severity of them in some cases, as lung conditions are one of the major risk factors for COVID.

Later on, I’ll explore the infrared sauna and COVID connection in more detail. First up though, let’s consider your risk of getting COVID in a sauna - a frequent question people have:

Precautions 101: Can You Catch COVID In A Sauna?

Many people ask: “can you catch COVID in a sauna?” I’ll now answer that questoin and consider the COVID and sauna risk.

Technically, what you’re asking here is can COVID survive in a sauna - or more aptly, can the virus that causes the COVID illness survive in a sauna. Before considering that link though, let’s have a short detour:

Scientific consensus, right now, is that indoor spread of the virus is much more likely than outdoor spread (6; 7; 8; 9; 10). Since 2019, indoor ventilation and air quality have been considered progressively more important until today.

Ventilation here, points at indoor CO2 levels and air quality, among others. Having fresh air coming into a room ensures that fewer viral particles or “aerosols” (which are subsumed into the air) remain inside that area. The fact that humans are spending more time indoors is one of the reasons the virus might spread more quickly during the winter seasons.

Now, here’s where the concept of a sauna comes in: saunas are the ultimate enclosed space. Saunas, in turn, when they’re not ventilated, are the ultimate space where air easily recirculates and is able to infect people. For that reason, if you use a sauna at all, make sure to ventilate the sauna properly before use. You’ll also have to be very careful spending time with another person inside a sauna.

If you want to measure ventilation, get a CO₂ monitor for your sauna and ensure levels are below 500 parts per million.

Next to ventilation, air purification and disinfecting surfaces before use could also lower your risk. These are common-sense strategies to lower COVID infection risk but become more important because of an enclosed space of a sauna.

Now, before you think saunas are the worst place you could ever spend time, there’s a cliffhanger - temperatures have an independent effect on their own:

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Can A Sauna Kill COVID?

The other part of the equation is the question of whether can a sauna kill COVID. So, do the viral particles die when they’re exposed to infrared heat or a hot air temperature? Let’s explore the answer to this question. Once again, we’re blessed with lots of high-quality research on this topic - I’ll explore these studies one by one (11; 12; 13; 14; 15; 16).

Under very high heat, over 150 degrees Celsius, the virus is killed very quickly. However, traditional saunas don’t even approximate those temperatures, let alone infrared saunas. Infrared saunas have a maximum temperature of 60 degrees Celsius.

Now, here’s the good part:

Between 25 degrees Celsius and ~34 degrees Celsius, higher temperatures increase the spread of the virus. Above 34 degrees, however, the spread slows down. And, given that infrared saunas are much hotter than 34 degrees, the spread of the virus slows down significantly, in a linear fashion with higher temperatures.

Therefore, if you ask “can I catch covid in a sauna”, a guesstimate based on the current science is that your risk is about the same as spending time in other indoor environments or even lower. A Sauna can kill COVID due to high temperatures but increases spread due to an enclosed space.

Moreover, higher humidity also decreases the overall spread of the virus. Humidity is normal in an infrared sauna though, unlike a traditional sauna. So, if you want to dramatically reduce COVID risk maximally, use a traditional sauna, although an infrared sauna shouldn’t increase your overall risk either.

So let's take a step back and connect some dots on this principle:

Temperatures and humidity are one of the reasons COVID is seasonal and peaks at the end of winter, and why cases go down until the end of summer. A sauna has properties of both that winter and summer environment, but, predominates towards the summer.

Next up, the burning question of what to do if you’re infected - can and should you use a sauna in that case?

Is It Safe To Use A Sauna During COVID?

Next up, is the question “is it safe to use a sauna during COVID”. Well, just with any viral infection, you have to be very careful using a sauna with COVID.

For many people - if you have significant symptoms -  using a sauna during COVID is a very bad idea. During illness, your body is already stressed. In such a case, you need rest, not to add stress on top of existing stress.

Sure, some people might get away with it. If you’ve tested positive for COVID but don’t have any symptoms, such as a fever, coughing, malaise, pain in your joints, a loss of smell, etcetera, then the case can be made to engage in some mild sauna sessions.

Now, lastly, there are some studies on using a sauna to prevent COVID and use it for treatment when your symptoms are reasonable and not excessive. Let’s explore these topics:

Infrared Sauna Safety For Treating Mild COVID Symptoms

So, lastly, I want to discuss using saunas as a preventive strategy against COVID. Remember I talked about how saunas could prevent other respiratory diseases in general, such as pneumonia and asthma - or help manage their symptoms at the very least (17; 18; 19).

Remember that I’d only recommend using a sauna if you’ve got very mild or no COVID symptoms. Also always consult with your physician if spending time inside a sauna is warranted.

• First, of all, breathing in hotter air might reduce the activity of the virus in your airways and lungs. Even though more research is needed on this topic, plausible biological explanations have been given in studies.
• Secondly, heated air and saunas, in general, activate your immune system. For instance, after a sauna session, your body increases its white blood cell count, which is the main cell of your immune system. Chronic inflammation is also impeded, which is a side-effect of many diseases and viral infections. If you’d like to learn more about this topic, read my blog about saunas and the immune system. In a way, the heat simulates a fever in your body, which is central to the immune system responses against infections.
• Thirdly, the higher heat has antiviral effects on its own, and by increasing the heat above the earlier 34 degrees threshold, viruses might not be able to survive. If you’re thus in an infrared sauna that’s 50 or 60 degrees Celsius, the higher heat might also kill the virus in your airways.
• Fourthly, the high heat counters “mucus” and “sputum”, and opens up your nasal passages and airways. Read my blog on nasal congestion and saunas for that topic.
• Lastly, heat exposure creates feelings of well-being and promotes a zen-like state of mind. Saunas also promote sleep quality, which you’ll need when recovering from COVID.
  

All in all, though, spending time inside an infrared sauna is really promising to counter and prevent COVID. And with that being said, let’s conclude:

Conclusion: Sauna COVID Risk And COVID In Sauna: Treat It Like Any Other Environment

So, overall, the covid in sauna risk is similar to what you’d see in other enclosed spaces. In other words, there’s no higher risk of getting COVID in a sauna than in a train or car or shop. Perhaps, due to high temperatures, the risk is even lower in a sauna.

Also, for both acute and preventative measures, the COVID and sauna combination may be a great one, depending on early research. Through several mechanisms, such as boosting your immune system and decongesting your airways, infrared saunas may be very helpful. Only use a sauna under physician supervision and if you don’t have symptoms or if the symptoms aren’t that intense.

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