You feel it coming on — the scratchy throat, the stuffy nose, the low-grade fatigue that signals a cold is settling in. Your first instinct might be to crawl under the covers, but if you have a sauna at home, you're probably wondering: should I use it?
The idea of "sweating out a cold" has been around for centuries. Finnish families have used traditional saunas as a frontline wellness tool for generations. But what does the actual science say? Can a sauna session help you recover faster, or could it make things worse?
Here's what the research tells us — and how to use your sauna wisely during cold season.
What Happens to Your Body in a Sauna
Before diving into the cold-specific research, it helps to understand what happens physiologically when you sit in a sauna. Whether you're using a traditional Finnish sauna heated to 170–200°F or an infrared sauna operating at a gentler 120–150°F, your body undergoes a cascade of responses to the heat.
Your core temperature rises by 1–2°F, mimicking a low-grade fever. Your heart rate increases, sometimes reaching 100–150 beats per minute — similar to moderate exercise. Blood vessels dilate, circulation improves, and you begin sweating heavily. At a cellular level, your body ramps up production of heat shock proteins (HSPs), which play critical roles in cellular repair, protein maintenance, and immune signaling.
This "controlled stress" is what makes regular sauna use so compelling from a health perspective. It's also the foundation for understanding how sauna relates to fighting off colds.
The Landmark Study: Regular Sauna Use and Cold Prevention
The most frequently cited study on sauna and colds was published in the Annals of Medicine in 1990 by Ernst et al. The researchers divided 50 volunteers into two groups: 25 who used a sauna regularly (one to two sessions per week) and 25 who abstained from sauna bathing entirely. Both groups tracked the frequency, duration, and severity of common colds over a six-month period.
The results were notable. The sauna group experienced significantly fewer cold episodes, particularly during the last three months of the study, when the incidence of colds was roughly cut in half compared to the control group. However, when members of the sauna group did get a cold, the duration and severity of their symptoms were not significantly different from the control group.
The takeaway from this study is important to understand correctly: regular sauna bathing appears to help prevent colds, but it doesn't necessarily shorten or reduce the severity of a cold once you already have one. The researchers noted that it seemed to take about three months of consistent sauna use before the protective effect kicked in — suggesting that the benefits are cumulative and tied to long-term immune conditioning, not a one-time intervention.
Can You "Sweat Out" a Cold? What Science Actually Says
Let's address the elephant in the room. The popular idea of "sweating out" a cold — sitting in a hot steam sauna and flushing the virus out through your pores — is a comforting concept, but the science doesn't support it in a literal sense.
A rigorous randomized controlled trial conducted in Berlin (published in 2010) specifically tested whether inhaling hot dry air in a sauna could reduce common cold symptoms. The study enrolled 157 patients with newly acquired colds and randomly assigned them to either inhale hot sauna air or room-temperature air (both groups sat inside a heated sauna). After tracking symptoms over seven days, the researchers found no significant difference in overall symptom severity between the two groups.
This doesn't mean sauna is useless when you're sick — it means the mechanism isn't about the hot air directly killing viruses or the sweat carrying pathogens out of your body. Your immune system eliminates viruses, not your sweat glands. What sauna can do is support the conditions that help your immune system do its job more effectively.
How Sauna Supports Your Immune System
While you can't sweat out a cold in the literal sense, there's a growing body of evidence showing that sauna use positively influences immune function in several meaningful ways.
Increased White Blood Cell Production
A study published in the Journal of Human Kinetics (Pilch et al., 2013) found that a single Finnish sauna session significantly increased white blood cell counts, including lymphocytes, neutrophils, and basophils — all of which are frontline defenders against infection. This immune response was observed in both trained athletes and untrained individuals, though athletes showed a more pronounced response.
White blood cells are your body's primary weapon against viruses and bacteria. The temporary increase in WBC count after sauna use suggests that regular heat exposure may keep your immune surveillance system more active and responsive.
Heat Shock Protein Activation
When your core temperature rises during a sauna session, your cells dramatically increase production of heat shock proteins, particularly HSP70. Research published in Experimental Gerontology has shown that 30 minutes in a 163°F sauna can increase HSP70 levels by approximately 49%.
These proteins do far more than protect cells from heat damage. HSPs have been shown to stimulate the innate immune system by activating dendritic cells and natural killer (NK) cells — both of which are essential for identifying and eliminating infected cells. Some preclinical research has even suggested that HSP70 can directly inhibit viral replication of influenza A, though more human studies are needed to confirm this effect.
Importantly, HSP levels build over time with regular heat exposure. Individuals who are heat-acclimated produce HSPs faster and at higher levels, which is another reason why consistent sauna use appears to be more protective than occasional sessions.
Reduced Chronic Inflammation
Chronic low-grade inflammation suppresses immune function and makes you more susceptible to infections. Multiple studies have linked regular sauna bathing to lower levels of C-reactive protein (CRP), a key marker of systemic inflammation. When your body isn't fighting unnecessary background inflammation, it has more resources available to mount an effective response against acute infections like the common cold.
Cortisol Regulation and Stress Reduction
Chronic stress is one of the most well-documented suppressors of immune function. Regular sauna use has been shown to help lower cortisol levels over time, which can have a meaningful downstream impact on your body's ability to fight off infections. Better stress management also contributes to improved sleep quality — and sleep is when your body produces and releases cytokines, the signaling proteins that help coordinate your immune response.
Sauna for Cold Symptom Relief
Even if sauna won't cure your cold faster, there are legitimate reasons it can make you feel better while you're fighting one off — as long as your symptoms are mild.
Nasal Congestion and Sinus Relief
If you've ever noticed your nose clearing up in a hot shower, the same principle applies in a sauna — but more effectively. Warm, humid air helps loosen mucus and moisturize irritated nasal passages. A traditional sauna is particularly effective for this because you can add water to the hot stones to create steam, which provides more direct relief for congestion. This is one reason why people dealing with sinus infections, seasonal allergies, or cold-related congestion often report feeling notably better after a session.
Muscle Ache and Body Pain Relief
Colds often come with body aches and general soreness. The improved circulation and deep heat from a sauna session — whether from a traditional heater or an infrared sauna — can help relax tight muscles and reduce that all-over achiness. Infrared saunas are particularly good at this because the infrared wavelengths penetrate deeper into tissue, providing relief at lower and more tolerable air temperatures.
Mood and Energy Boost
Feeling miserable is part of having a cold, and sauna sessions have been consistently shown to promote the release of endorphins and dopamine. These neurotransmitters help manage pain perception, improve mood, and promote a general sense of well-being — which can make a meaningful difference when you're dragging through a cold.
Traditional Sauna vs. Infrared Sauna for Colds
Both types of sauna can be beneficial during cold season, but they work somewhat differently and may suit different situations.
Traditional saunas operate at higher temperatures (150–200°F) and allow you to add water to sauna heater stones for steam. This makes them especially effective for congestion relief and creating the fever-mimicking effect that activates immune responses. The combination of high heat and humidity is what Finnish sauna culture has relied on for centuries as a wellness practice during cold and flu season.
Infrared saunas operate at lower temperatures (120–150°F) but use infrared wavelengths that penetrate directly into body tissue, raising your core temperature efficiently without the intensity of extreme ambient heat. If you're feeling weak, fatigued, or mildly feverish from a cold, an infrared sauna may be more comfortable and easier to tolerate while still providing immune-supporting benefits.
Hybrid saunas give you the best of both worlds — combining traditional heating with infrared panels so you can adjust the experience based on how you're feeling on any given day. When you're healthy, crank up the traditional heat for an intense session. When you're coming down with something, switch to gentler infrared wavelengths for a more comfortable immune-support session.
If you're not sure which type fits your lifestyle and wellness goals best, our guide on choosing the best sauna for your home breaks down the key differences in detail.
When You Should NOT Use a Sauna With a Cold
Sauna use during a mild cold can be fine — and even helpful — for many people. But there are important situations where you should skip the sauna entirely:
If you have a fever. Your body is already working hard to raise its temperature to fight the infection. Adding external heat on top of a fever can push your core temperature to dangerous levels and puts extra strain on your cardiovascular system. Wait until your fever has broken for at least 24 hours before using the sauna.
If you have the flu (not just a cold). Influenza is a much more serious illness than the common cold and typically involves higher, longer-lasting fevers, intense body aches, and more severe fatigue. Sauna use with the flu increases the risk of dehydration and cardiovascular stress. Rest, fluids, and medical advice should take priority.
If you're severely dehydrated. Colds already deplete your body's fluid levels through mucus production, reduced appetite, and sometimes mild fever. A sauna session adds significant fluid loss through sweat. If you haven't been drinking enough water, the combination can lead to dehydration that actually impairs immune function and slows recovery.
If you feel dizzy, lightheaded, or extremely fatigued. Listen to your body. If standing up feels like an effort, a sauna session isn't going to help. Your energy is better spent resting.
If you're using a shared or public sauna. This is an etiquette and public health point. If you have a contagious cold, using a public sauna or gym sauna exposes others to your virus. This is one of the best arguments for having a home sauna — you get the health benefits without worrying about infecting others or picking up someone else's germs.
How to Use Your Sauna Safely During a Cold
If your symptoms are mild — think runny nose, light congestion, scratchy throat, and mild fatigue (but no fever) — a sauna session can be a soothing and potentially beneficial part of your recovery routine. Here's how to do it safely:
Keep sessions shorter than usual. If you normally do 15–20 minutes, scale back to 10–15 minutes. Your body is already under stress from fighting the infection, so pushing through a marathon session is counterproductive.
Lower the temperature slightly. There's no need to go full intensity when you're under the weather. Drop the temperature 10–20°F below your usual setting or choose the infrared mode if you have a hybrid sauna.
Hydrate aggressively. Drink water before, during, and after your session. Consider adding electrolytes to your water since you're losing both fluids and minerals through sweat and from the cold itself.
Add steam for congestion. If you're using a traditional sauna, gently pour water over the heater stones to create steam. Adding a few drops of eucalyptus oil to the water can further help open up your sinuses (check that your specific heater and sauna manufacturer support essential oil use).
Skip the cold plunge. Under normal circumstances, alternating between sauna heat and cold plunge immersion is excellent for recovery and immune conditioning. But when you're actively sick, the cold shock adds additional stress that your body doesn't need. Save the contrast therapy routine for when you're healthy.
Rest afterward. Don't jump back into your day after a sauna session when you're sick. Lie down, stay warm, and let your body continue its recovery work. A sauna session before bed can be particularly effective since it promotes deeper sleep — and sleep is the single most important thing you can do when fighting a cold.
Building Long-Term Immune Resilience With Sauna
The most compelling evidence for sauna and cold prevention isn't about using it as a quick fix when you're already sick. It's about using it consistently as part of your wellness routine so your immune system is better equipped to handle whatever cold season throws at you.
Here's what the research suggests for building immune resilience:
Frequency matters. The 1990 Ernst et al. study used one to two sessions per week, and the Finnish KIHD (Kuopio Ischaemic Heart Disease Risk Factor) study — which linked frequent sauna use to reduced risk of pneumonia and respiratory disease — found that four to seven sessions per week provided the greatest protective effect. Aim for at least two to three sessions per week to support immune function.
Duration matters. Sessions of 15–30 minutes appear to be most effective for stimulating heat shock protein production and white blood cell mobilization. Shorter sessions may not raise core temperature enough, while extremely long sessions can be counterproductive due to dehydration and excessive stress.
Consistency matters most. The cold-prevention benefits appear to build over time. The Ernst study showed the protective effect becoming most pronounced after three months of regular use. This isn't a weekend warrior activity — it's a lifestyle practice.
Having a sauna in your home makes consistency dramatically easier. When your sauna is 20 steps away instead of a 20-minute drive to a gym or spa, you're far more likely to maintain the regular routine that produces the best results. Whether you choose a compact indoor sauna, a beautiful outdoor barrel or cabin sauna, or a space-efficient infrared sauna, the best sauna for immune health is the one you'll actually use regularly.
Complementary Wellness Strategies
Sauna works best as part of a holistic approach to immune health, not as a standalone silver bullet. Here are some strategies that pair well with regular sauna use during cold season:
Contrast therapy (when healthy). Alternating between sauna heat and cold plunge immersion has been shown to enhance circulation, reduce inflammation, and strengthen the body's adaptive stress response. This hot-cold cycling can amplify the immune benefits of sauna use alone — just make sure you're doing it when you're healthy, not while actively fighting an infection.
Red light therapy. Many sauna users are combining their sessions with red light therapy, which uses specific wavelengths (typically 660nm red and 850nm near-infrared) to support cellular energy production, reduce inflammation, and promote tissue repair. While the direct evidence for red light therapy and cold prevention is still emerging, the anti-inflammatory and circulation-boosting effects complement what sauna heat provides. You can learn more in our guide on how to add red light therapy to your sauna.
Adequate sleep, nutrition, and hydration. No amount of sauna use can compensate for chronic sleep deprivation, poor nutrition, or dehydration. These fundamentals are the foundation that makes every other wellness practice — including sauna — more effective.
Regular exercise. Physical activity is one of the most well-established immune boosters, and research suggests that exercise paired with sauna use may provide synergistic benefits for respiratory health. Some studies have found that the combination of regular exercise and frequent sauna bathing reduces pneumonia risk more than either practice alone.
The Bottom Line
So, is sauna good for a cold? The honest, research-backed answer is nuanced:
For cold prevention: Yes — and the evidence is encouraging. Regular sauna use (two or more sessions per week over several months) is associated with fewer cold episodes, likely due to enhanced white blood cell production, heat shock protein activation, reduced chronic inflammation, and improved stress management. The benefits are cumulative and build with consistent use.
For treating an active cold: It depends. Sauna won't kill the virus or dramatically shorten your cold, but mild sessions can provide meaningful symptom relief — especially for congestion, body aches, and general malaise. The key is keeping sessions short, staying hydrated, and avoiding the sauna entirely if you have a fever or flu-like symptoms.
For long-term immune resilience: Absolutely. The strongest case for sauna and immune health is the long game. Consistent heat exposure trains your body's stress response systems, keeps immune cells active and responsive, and reduces the chronic inflammation that makes you vulnerable to infections in the first place.
If you're ready to make sauna a cornerstone of your wellness routine, explore our full collection of traditional saunas, infrared saunas, and hybrid saunas to find the right fit for your space and goals. Add sauna accessories like a quality thermometer, bucket and ladle set, and proper ventilation to optimize every session. And if you're building a complete home wellness setup, don't overlook our contrast therapy collection for when you're ready to take your immune conditioning to the next level.
Your immune system is your most valuable asset during cold season. Give it every advantage you can.
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