You feel it coming on — the scratchy throat, the stuffy nose, the bone-deep fatigue that tells you a cold is taking hold. If you have a sauna at home (or access to one), the temptation is obvious: fire it up, sit in the heat, and sweat this thing out.
But should you? The relationship between sauna use and the common cold is more nuanced than most wellness content would have you believe. Some of the science is encouraging. Some of it will surprise you. And some popular claims about "sweating out a cold" simply don't hold up under scrutiny.
This article breaks down what the clinical research actually tells us about saunas and colds — from prevention to symptom relief to the situations where a sauna session could make things worse.
A Quick Primer: What Is the Common Cold, Really?
The common cold is an acute viral infection of the upper respiratory tract, primarily caused by rhinoviruses (though more than 200 different viruses can be responsible). Most adults catch two to three colds per year, making it the most widespread infectious illness in humans.
A few things worth clarifying upfront. First, colds aren't caused by cold weather itself. The reason cold season peaks during fall and winter is largely because people spend more time indoors in close quarters, making viral transmission easier. Cold temperatures may also slightly suppress certain aspects of immune function in the nasal passages, but the virus — not the weather — is what makes you sick.
Second, because colds are viral, antibiotics don't work against them. Treatment is entirely symptomatic: rest, hydration, and comfort measures to manage the runny nose, sore throat, coughing, and fatigue until your immune system clears the infection on its own, usually within seven to ten days.
This is exactly why people look for alternative approaches — like sauna bathing — to either speed up recovery or prevent colds from happening in the first place.
What Happens to Your Body in a Sauna
Before we examine the cold-specific research, it helps to understand the physiological chain reaction that occurs during a sauna session. Whether you're sitting in a traditional Finnish sauna heated to 170–200°F or an infrared sauna operating at a gentler 120–150°F, your body responds to the heat in several measurable ways:
Your core temperature rises by 1–2°F, mimicking a low-grade fever. Fever is one of the body's primary defense mechanisms against infection — it creates an environment where pathogens struggle to replicate efficiently. A sauna session triggers a similar (though externally induced) temperature increase.
Your heart rate increases to 100–150 beats per minute, comparable to moderate-intensity exercise. This drives increased blood flow throughout the body, delivering oxygen and immune cells more efficiently to tissues and organs.
Blood vessels dilate and circulation improves. The vasodilation that occurs during heat exposure enhances the transport of white blood cells and other immune components through your bloodstream.
You begin sweating heavily. Sweat is primarily composed of water, sodium, and small amounts of minerals. Despite popular claims, sweat doesn't meaningfully "flush out toxins" or remove pathogens from the body. Its primary purpose is thermoregulation — cooling you down.
Your body produces heat shock proteins (HSPs). This is where things get particularly interesting for immune function. Research shows that HSP levels can increase by approximately 50% after a 30-minute session in a 163°F sauna. Once activated, these proteins can remain elevated for up to 48 hours. HSPs play documented roles in both innate and adaptive immunity — they help protect cells from stress, support protein repair, and can stimulate immune responses through toll-like receptor activation.
The Research: Can Saunas Prevent Colds?
This is where the science is most encouraging. The landmark study on sauna use and cold prevention was conducted at the University of Vienna by Ernst et al. and published in the journal Annals of Medicine in 1990. The researchers tracked 50 volunteers over six months — 25 who used the sauna regularly (one to two sessions per week) and 25 controls who abstained.
The results were notable: the sauna group experienced significantly fewer episodes of the common cold compared to the control group. This protective effect was most pronounced during the final three months of the study period, when the incidence of colds in the sauna group was roughly cut in half compared to controls.
There's an important detail here that most articles miss. The duration and severity of colds that did occur were not significantly different between the two groups. In other words, regular sauna use appeared to help people avoid catching colds altogether, but it didn't make the colds shorter or milder when they did happen. The benefit was preventive, not therapeutic — and it took roughly three months of consistent use before the protective effect became apparent.
This suggests that the immune benefits of sauna bathing are cumulative and tied to long-term conditioning of the immune system, not a one-time intervention you can deploy when you feel the sniffles coming on.
The Immune Mechanism Behind Prevention
So how does regular sauna use strengthen immune defenses over time? Multiple studies have examined the effect of sauna bathing on white blood cell profiles, and the findings are consistent:
A 2013 study published in the Journal of Human Kinetics found that a single Finnish sauna session was enough to increase circulating white blood cell counts, including lymphocytes, neutrophils, and basophils. The immune response was more pronounced in trained athletes than in untrained individuals, but both groups showed measurable increases.
A follow-up study published in the International Journal of Hyperthermia in 2023 examined both single sessions and a series of ten sauna baths. The researchers concluded that sauna bathing can improve immune response, but the benefits are most meaningful when undertaken as a series of treatments rather than isolated sessions — reinforcing the finding from the 1990 Ernst study that consistency is what matters.
The proposed mechanism involves several overlapping pathways: the heat-induced rise in core temperature activates heat shock proteins and stimulates white blood cell production; improved circulation enhances the delivery of immune cells throughout the body; and the repeated stress-recovery cycle of regular sauna use conditions the immune system to respond more efficiently to real threats.
The Research: Can a Sauna Help Once You Already Have a Cold?
This is where the science becomes less supportive — and where the popular belief in "sweating out a cold" collides with clinical reality.
The most rigorous study on this question is a randomized controlled trial conducted in Berlin, published in the Medical Journal of Australia in 2010. Researchers enrolled 157 patients with active cold symptoms and randomly assigned them to two groups: one inhaled hot dry air inside a heated sauna, while the other inhaled room-temperature air in the same sauna environment (both groups wore winter coats to control for body heat exposure). The study ran for three days with follow-up through day seven.
The conclusion was unambiguous: inhaling hot air in a sauna had no significant impact on overall cold symptom severity. Participants who breathed the hot sauna air showed no meaningful difference in symptom scores, medication use, or general feelings of illness compared to those who breathed room-temperature air.
A 2017 Cochrane-style analysis reviewing six related trials supported these findings, concluding that heated or humidified air has not been shown to provide consistent relief from common cold symptoms.
This doesn't mean a sauna session is completely useless when you're sick. But it does mean we need to be precise about what it can and can't do.
What a Sauna Might Help With During a Cold
Temporary congestion relief. If you're using a traditional sauna and pour water over the heater stones to generate steam, the warm, humid air can help loosen mucus and moisten irritated nasal passages. This is the same principle behind a hot shower providing short-term sinus relief — it doesn't treat the infection, but it can make breathing easier for a while.
Muscle and body ache relief. The heat from a sauna session improves blood circulation and relaxes tense muscles, which may ease the generalized achiness that often accompanies a cold. Think of it as a full-body heating pad rather than a medical treatment.
Stress reduction and better sleep. Being sick is inherently stressful, and stress impairs immune function. A gentle sauna session can activate your parasympathetic nervous system (the "rest and digest" response), lower cortisol levels, and promote the kind of relaxation that supports better sleep — which is one of the most important factors in cold recovery.
Endorphin release. Sauna exposure stimulates the release of beta-endorphins (your body's natural pain reliever) and dopamine (a feel-good neurotransmitter). These won't cure your cold, but they can provide temporary comfort when you're feeling miserable.
Can You "Sweat Out" a Cold? Debunking the Myth
The idea that sitting in a hot room and sweating profusely will flush a cold virus from your body is one of the most persistent wellness myths. It's comforting, it's intuitive, and it doesn't hold up.
Laboratory analysis of sweat shows that it's composed primarily of water, sodium chloride, and trace amounts of minerals and lipids. It doesn't contain significant quantities of pathogens, viral particles, or "toxins" that would explain a therapeutic effect from heavy sweating. Cold viruses replicate in the cells of your upper respiratory tract — they aren't circulating in a form that your sweat glands can access or expel.
When people report feeling better after a sauna session during a cold, the improvement is likely attributable to the temporary symptom relief described above (congestion clearing, muscle relaxation, endorphin release) rather than any direct antiviral action. These are real benefits, but they're comfort measures — not cures.
Traditional Sauna vs. Infrared Sauna for Colds
Different types of saunas affect the body in different ways, and this matters when you're considering a session during cold season.
Traditional saunas heat the air to 170–200°F, creating an intensely hot environment. When you pour water over the heater stones (löyly in Finnish), you produce steam that adds humidity to the air. This steam component is particularly relevant for cold sufferers because the moist heat can help open blocked sinuses and ease congestion more effectively than dry heat alone. If congestion relief is your primary goal, a traditional sauna with steam has the edge. Browse traditional saunas here.
Infrared saunas operate at lower air temperatures (typically 120–150°F) and heat your body directly through infrared radiation rather than heating the surrounding air. Because the ambient temperature is lower, many people find infrared sessions more tolerable when they're feeling run down. Infrared saunas are also effective at raising core body temperature, promoting sweating, and triggering heat shock protein production — all of the immune-conditioning benefits apply here. However, they don't produce steam, so they won't provide the same level of congestion relief as a traditional sauna session with löyly. Browse infrared saunas here.
Hybrid saunas — which combine a traditional electric heater with built-in infrared panels — offer the most flexibility. You can use the traditional heater with steam for sinus relief, switch to the infrared panels for a gentler session when energy is low, or use both for a comprehensive heat therapy experience. For households that want to optimize their sauna for both wellness and cold-season comfort, a hybrid model covers the most ground. Read our full infrared vs. traditional sauna comparison for a deeper dive into the differences.
When to Avoid the Sauna Entirely
There are situations where using a sauna while sick can do more harm than good. These are non-negotiable, regardless of sauna type:
If you have a fever. Your body temperature is already elevated as your immune system fights the infection. Adding external heat on top of a fever can push your temperature into dangerous territory, placing additional cardiovascular stress on a body that's already working overtime. If you have a fever, skip the sauna — no exceptions.
If you have the flu, not just a cold. Influenza is a significantly more serious illness than the common cold. It typically involves higher and longer-lasting fevers, extreme fatigue, severe body aches, and greater risk of complications. The flu demands rest, not heat stress. If you suspect you have the flu rather than a cold, stay out of the sauna and consult your healthcare provider.
If you're experiencing severe symptoms. Difficulty breathing, extreme dizziness, intense headache, chest pain, or debilitating fatigue are all signals that your body needs rest and possibly medical attention — not a sauna session.
If you're dehydrated. Colds naturally contribute to mild dehydration (through mucus production, reduced appetite, and sometimes fever). A sauna session causes significant additional fluid loss through sweat. The combination can lead to dangerous levels of dehydration that impair your immune system's ability to function and can cause dizziness, fainting, or worse.
If you'd be using a public or shared sauna. If you have an active cold, you're contagious. Using a communal sauna at a gym, spa, or community center exposes others to your virus. If you're going to use a sauna while mildly sick, do it in the privacy of your own home.
How to Use Your Sauna Safely During a Cold
If your symptoms are mild (stuffy nose, sore throat, low energy — but no fever), a careful sauna session may provide some comfort. Here's how to do it wisely:
Keep sessions short. Limit your time to 10–15 minutes. This isn't the time for marathon sessions or multiple rounds. Get in, get the comfort benefit, and get out.
Lower the temperature. Drop the heat 10–20°F below your usual setting. If you normally sauna at 180°F, try 155–165°F. If you're using an infrared sauna, stay at the lower end of its range. Your body is already under stress from fighting the infection — you don't need to push it further.
Hydrate aggressively. Drink water before, during, and after your session. Consider adding electrolytes to replace the minerals you're losing through both sweating and cold symptoms. This is critical — dehydration will make you feel worse, not better.
Use steam for congestion. If you're in a traditional sauna, gently pour water over the heater stones to create steam. A few drops of eucalyptus oil added to the water can further help open your sinuses (check your heater manufacturer's guidelines on essential oil use first).
Skip the cold plunge. If your normal routine includes cold plunge immersion after the sauna, skip it while you're sick. Contrast therapy is excellent for immune conditioning when you're healthy, but the shock of cold water on a body already fighting an infection can add unnecessary stress. Save the cold plunge for when you're feeling better.
Rest afterward. After your session, wrap up in something warm, continue hydrating, and rest. A mild sauna session should be followed by relaxation, not activity.
The Real Power Move: Using Your Sauna to Prevent Colds
If there's one clear takeaway from the research, it's this: sauna bathing is most effective as a cold-prevention strategy, not a cold treatment. The data consistently points toward regular, long-term sauna use as the key to building immune resilience.
Based on the available evidence, a solid prevention-focused sauna protocol looks something like this:
Frequency: Two to three sessions per week, year-round. The Ernst study showed the protective effect kicking in after about three months of one to two weekly sessions. More frequent use (four to seven times per week) has been associated with even broader health benefits in large Finnish cohort studies, though the cold-specific prevention data is based on the lower frequency.
Duration: 15–20 minutes per session is sufficient for triggering the heat shock protein response and white blood cell mobilization that underpin the immune benefits. You don't need to spend 45 minutes in the sauna to get the immune conditioning effect.
Consistency: This is the factor that matters most. The benefits are cumulative and depend on regular exposure to heat stress over time. A sporadic session here and there won't produce the immune-conditioning effect seen in the research. Build it into your weekly routine the same way you would exercise.
Pair with contrast therapy (when healthy). Alternating between sauna heat and cold plunge immersion has been shown to enhance circulation, reduce systemic inflammation, and strengthen the body's adaptive stress response. This hot-cold cycling can amplify the immune benefits of sauna use alone — just do it when you're healthy, not when actively fighting a cold.
Why a Home Sauna Changes the Equation
Here's a practical reality that the clinical studies don't address but that matters enormously for real-world results: consistency depends on convenience. When your sauna is in your backyard or a spare room — 20 steps away instead of a 20-minute drive to a gym — you're dramatically more likely to maintain the regular routine that produces the best results.
You also eliminate the public hygiene concern. During cold season, using a communal sauna means exposing yourself to other people's germs (and exposing others to yours if you're sick). A home sauna lets you maintain your routine in a controlled, private environment, whether you're perfectly healthy or dealing with mild symptoms.
Whether you go with a compact indoor infrared sauna that plugs into a standard wall outlet, a beautiful outdoor barrel or cabin sauna for the backyard, or a versatile hybrid model that gives you both heating options — the best sauna for immune health is the one you'll actually use three times a week, every week, all year long.
The Bottom Line
Can a sauna cure your cold? No. The clinical evidence is clear that sauna heat does not significantly reduce the severity or duration of a common cold once symptoms have set in.
Can a sauna help prevent colds? Yes — and this is where the real value lies. Regular sauna use over a period of months has been shown to reduce the incidence of common colds, likely through cumulative effects on heat shock protein production, white blood cell mobilization, and overall immune system conditioning.
Can a sauna provide comfort during a mild cold? Absolutely. Temporary congestion relief from steam, muscle relaxation, stress reduction, and endorphin release can all make you feel meaningfully better while your body does the actual work of clearing the virus.
The smartest approach is to think of your sauna as an immune-building tool — something you use consistently when you're healthy to reduce your chances of getting sick in the first place. If you do catch a cold, a gentle session can offer comfort, but the foundation of your recovery is rest, hydration, and time.
Ready to make regular sauna bathing part of your wellness routine? Explore our full collection of saunas — from infrared and traditional models to outdoor saunas built for year-round use. Every order ships free with financing options available.
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