Last updated: May 2026
In October 2024, a Helsinki-based physiotherapist named Mira told our team something most clients only suspect: she had not taken a sick day in nine years, and she credited her Finnish sauna ritual of four sessions a week. She is not alone. A landmark Austrian trial published in Annals of Medicine found that participants who took regular saunas reported roughly half as many common colds over a six-month period as a non-sauna control group (Ernst et al., 1990).
If you have ever stood in front of your sauna with a sniffle and wondered, does a sauna help a cold or make it worse, the honest answer is “it depends on the stage of the illness.” There is solid evidence for sauna’s role in reducing how often you catch colds, modest evidence for symptom relief once a cold has started, and clear contraindications for certain conditions where sauna use is dangerous. This guide separates each strand cleanly.
As a manufacturer that has installed saunas in 38 years of residential, hotel, and clinical wellness projects, our team is asked this question almost weekly during the autumn and winter months. Below, we walk through what the peer-reviewed research shows, when sauna use can ease symptoms, when to skip the session, the safety rules to follow, and how regular use supports immune resilience year-round. Considering a sauna for your home wellness routine? Explore our custom sauna range or request a free consultation with our design team.
Does a sauna help a cold, according to the research?
Yes, with caveats. Regular sauna use, defined as two or more sessions per week, is associated with roughly 30–50 % fewer common colds over time. Once a cold has already started, a single sauna session may temporarily ease congestion and muscle ache, but it does not shorten the illness. The strongest evidence supports prevention, not cure.
What did the famous Ernst study find?
The 1990 Ernst trial randomised 50 participants to either regular sauna bathing twice weekly or a no-sauna control group, then tracked common-cold incidence for six months. During the second three-month observation period, the sauna group experienced significantly fewer episodes of cold infection (Ernst et al., 1990). The protective effect appeared only after sustained use, not from a single session.
How robust is the more recent evidence?
A large Finnish prospective cohort study followed 1,935 men for an average of 25.6 years and found that those who used a sauna four to seven times per week had a 41 % lower risk of pneumonia compared to once-weekly users (Kunutsor, Laukkanen & Laukkanen, 2017, European Journal of Epidemiology). The dose-response relationship was clear: more frequent sauna sessions tracked with lower respiratory infection risk.
When can a sauna help with cold symptoms?
A sauna can help with cold symptoms during the very early “scratchy throat” stage or once the worst is over and you are recovering. Heat exposure increases nasal blood flow, loosens mucus, and provides short-term symptom relief. If you have a low fever, body aches, or chest infection, the answer is no: skip the sauna and rest until those signs resolve.
Which symptoms respond best to sauna heat?
Three common cold symptoms respond reasonably well to sauna or steam exposure: nasal congestion, sinus pressure, and the muscle stiffness that often accompanies the early phase. The warmth dilates blood vessels in the nasal passages and helps thin mucus. A 2017 Cochrane review concluded that heated humidified air offers modest symptomatic relief in upper respiratory infections (Singh et al., 2017).
Should you choose dry or humid heat for cold symptoms?
For respiratory and sinus symptoms, humid heat works better than dry. A bespoke steam room or a Bio Sauna running at 50 °C with 40–55 % humidity is gentler and more decongesting than a 90 °C Finnish sauna. For muscle aches without respiratory involvement, a traditional Finnish sauna at lower temperatures (60–70 °C) is acceptable provided you are not feverish.
Why early-stage timing matters
The “scratchy throat” stage typically reflects an immune response just beginning to mobilise. Heat exposure at this point may help by raising core temperature briefly, mimicking a mild fever response that supports white-cell activity. Once a cold is fully established with fever, fatigue, or chest involvement, heat stress competes with the body’s recovery resources rather than supporting them.
When should you avoid a sauna during sickness?
Avoid the sauna entirely if you have a fever above 37.5 °C (99.5 °F), chest infection, productive cough, gastrointestinal illness, or any rapid heart rate, dizziness, or shortness of breath. Sauna use during fever raises core temperature further, accelerates dehydration, and stresses an already stressed cardiovascular system. The same caution applies to the elderly, pregnant women, and anyone with cardiovascular disease.
Why fever and sauna are a dangerous combination
A normal Finnish sauna session raises core body temperature by 0.5–1.5 °C (Hannuksela & Ellahham, 2001, American Journal of Medicine). Adding that to an already fever-elevated baseline can push core temperature into hyperthermia territory. Heart rate climbs by 60–70 beats per minute during sauna use, which compounds the cardiovascular load of fighting infection.
Which medical conditions are absolute contraindications?
Skip the sauna entirely during illness if you have any of the following:
- Fever or recent fever within 24 hours
- Chest infection, bronchitis, or pneumonia symptoms
- Active gastrointestinal illness (vomiting or diarrhoea)
- Diagnosed cardiovascular disease without medical clearance
- Pregnancy, particularly first trimester
- Recent heart attack, stroke, or unstable angina
- Severe asthma flare or uncontrolled asthma
- Any infection with chills, sweats, or rapid heart rate
What about the day after a cold ends?
Once your cold symptoms have resolved for at least 48 hours and your temperature is normal, a short, mild sauna session can be a comfortable way to ease residual stiffness. Start with 8–10 minutes at lower temperature, hydrate well, and skip the cold plunge. Build back to your usual routine over several sessions rather than jumping straight in.
Building a sauna for your home wellness routine? Our team designs cabins to support immune resilience, recovery, and long-term cardiovascular health. Request a free consultation and we will help you design a private wellness suite you will use for decades.
How does regular sauna use strengthen the immune system?
Regular sauna use strengthens the immune system through three measurable mechanisms: a transient increase in white blood cell counts after each session, sustained reductions in inflammation markers, and improved respiratory tract resilience. A single 30-minute session has been shown to raise lymphocyte and basophil counts in athletes within an hour of exposure (Pilch et al., 2014, Journal of Human Kinetics).
What happens to white blood cells during a sauna session?
The 2013 Pilch study measured white blood cell profiles in 20 healthy male participants before and after a single 30-minute Finnish sauna session at 90 °C. Total leukocyte counts, including lymphocytes, neutrophils, and basophils, increased significantly within an hour after the session, with athlete participants showing larger gains than non-athletes. The transient mobilisation of immune cells is one proposed mechanism behind the long-term protection seen in cohort data.
How does heat exposure affect inflammation?
Repeated heat exposure increases production of heat-shock proteins, which support cellular repair and modulate inflammation. A 2018 evidence review in Mayo Clinic Proceedings concluded that regular sauna bathing is associated with lower levels of systemic inflammation markers like C-reactive protein and fibrinogen (Laukkanen et al., 2018). Lower baseline inflammation is generally protective against infection and chronic disease alike.
Why does respiratory health improve with regular sauna use?
The Kunutsor 2017 prospective cohort found a clear inverse relationship between sauna frequency and pneumonia risk. The proposed mechanisms include improved mucociliary clearance, transient warming of the respiratory tract, and stress-adaptation effects on the autonomic nervous system. Regular sauna users essentially train their respiratory system to handle thermal stress, which appears to translate to better defence against infection.
What does this look like in practice?
In November 2025, a Munich household of four (parents and two school-age children, both prone to winter respiratory infections) began using their Sauna Dekor Finnish sauna three evenings a week. The mother, Anja, reported that during the 2025–26 cold season, the family collectively missed eight school and work days from colds, compared to 22 the previous winter. Anecdotal but consistent with the research.
What are the safety guidelines for sauna use during illness?
The core safety rule is simple: if you have a fever, infection symptoms below the neck, or any cardiovascular concern, skip the sauna. If you are using a sauna at the early or recovery stage of a mild cold, limit sessions to 10–15 minutes, hydrate with at least 500 ml of water before and after, avoid alcohol, and do not combine with cold plunge or contrast therapy. Listen to your body and exit early if you feel unwell.
How long should sessions be when you are slightly under the weather?
A short 8–12 minute session at moderate temperature (60–75 °C for Finnish, 50 °C for Bio Sauna or infrared cabin) is enough at the early stage of a cold or in recovery. Skip the second round and the cold plunge. Save the longer 15–20 minute high-heat sessions for when you are fully well.
What about hydration and electrolytes?
Sauna sessions cause significant fluid loss, typically 300–800 ml of sweat per session. When you are unwell, dehydration risk is already higher. Drink water before entering, sip during longer sessions, and replenish 500–1,000 ml after exiting. For longer sessions or hot climates, consider a small electrolyte addition; plain water is fine for shorter sessions.
What signs mean you should leave immediately?
Exit the sauna at the first sign of:
- Dizziness or light-headedness
- Rapid or irregular heart rate
- Nausea or stomach discomfort
- Chest tightness or shortness of breath
- Headache that worsens during the session
- Tingling or numbness in the limbs
- Any feeling that “this isn’t right”
How often should you use a sauna to reduce cold frequency?
Two to four sessions per week is the threshold most studies associate with measurable immune benefits, including roughly 30–50 % fewer common colds reported in the Ernst trial and a 41 % lower pneumonia risk in the Kunutsor cohort. Daily sauna use does not appear to add significantly more protection beyond four sessions per week, but it does not appear to be harmful for healthy adults either.
What does an effective weekly routine look like?
A protective routine for a healthy adult might look like this:
- Two evening sessions per week of 15–20 minutes at 75–90 °C
- One morning or post-exercise session of 10–15 minutes
- Optional fourth session at the weekend, longer if desired
- Adequate hydration and at least one rest day between intense sessions
- Skip if you are travelling fatigued, sleeping poorly, or unwell
Does the type of sauna matter for immune benefits?
Most peer-reviewed cold and respiratory research has been conducted on traditional Finnish saunas. Infrared saunas show similar cardiovascular and inflammation results in available studies but have less direct evidence on cold prevention. A Bio Sauna offers a middle ground at 45–60 °C with humidity, which suits people who find Finnish heat too intense.
How long does it take to see immune benefits?
The Ernst trial saw measurable cold-frequency reduction in the second three-month period, suggesting consistent use over roughly 8–12 weeks before benefits become visible. Cardiovascular and longevity benefits in the long-term Finnish cohorts emerged with years of consistent use. Habit-building matters more than intensity here.
Should you use a sauna when you have a cold? Bottom line
Use a sauna early in a mild cold (scratchy throat, mild congestion, no fever) to support comfort, and use one regularly when well to reduce how often you get sick in the first place. Skip the sauna entirely if you have fever, chest involvement, or any below-the-neck symptoms. The research strongly supports prevention; the case for cure is weaker but not zero.
If you are designing a sauna for your home, the immune-support angle is one of the most consistent year-round wellness arguments. Combined with cardiovascular benefits, sleep improvement, and stress reduction, it is one of the easiest at-home wellness investments to justify medically. The 38 years of installations our team has completed in private homes and hotels confirm that the most loyal users are those who build sauna into their weekly routine.
Ready to design a sauna that supports year-round immune health? Our manufacturer-direct team handles design, manufacturing, delivery, and installation worldwide. Request a free consultation and we will help you specify a Finnish, infrared, or Bio Sauna that fits your home, your budget, and your wellness goals.
Frequently asked questions about saunas and colds
Can a sauna give you a cold?
No. Saunas do not cause respiratory infections; viruses do. However, sauna use during fever or illness can worsen symptoms, dehydrate you, and stress your cardiovascular system. The risk is in mistiming sauna use, not in the sauna itself.
Is a sauna or steam room better for a stuffy nose?
A steam room generally works better for nasal congestion because the 100 % humidity directly hydrates nasal passages and loosens mucus. A Finnish sauna at low humidity helps less with congestion but more with body aches. Both can ease early-cold symptoms safely.
How quickly do immune benefits from regular sauna use appear?
Measurable reduction in cold incidence appeared in the Ernst trial after roughly three months of twice-weekly sauna use. Acute white-cell mobilisation occurs within an hour of a single session, but lasting protective effects need sustained, regular use over weeks to months.
Can children use a sauna for cold prevention?
Children over six years of age can use a sauna safely with a parent for short 5–10 minute sessions at lower temperatures (50–70 °C). Below age six, sauna use is generally not recommended. Children with any acute infection should skip the sauna entirely until they are well.
Does an infrared sauna help with colds the same way?
Infrared saunas show similar inflammation and cardiovascular benefits in available research, but direct evidence on cold prevention is thinner than for Finnish saunas. The mechanism likely overlaps; the dose-response relationship is less well characterised. Use the same safety rules for both.
Can I take a sauna with antibiotics?
Generally yes for healthy adults on standard oral antibiotics, but only if you are no longer feverish and the underlying infection is resolving. Some antibiotics, photosensitisers in particular, can interact with heat exposure or affect sweating, so consult your prescribing doctor first.
Does sauna use replace flu vaccination or hand hygiene?
No. Sauna is a complementary lifestyle factor, not a substitute for vaccination, hand hygiene, or other proven public health measures. Think of regular sauna use as one component of resilience, alongside sleep, nutrition, exercise, and standard preventive care.
Sources
- Ernst, E., Pecho, E., Wirz, P., & Saradeth, T. (1990). Regular sauna bathing and the incidence of common colds. Annals of Medicine, 22(4), 225–227. PubMed
- Kunutsor, S. K., Laukkanen, T., & Laukkanen, J. A. (2017). Sauna bathing reduces the risk of respiratory diseases: a long-term prospective cohort study. European Journal of Epidemiology, 32(12), 1107–1111. PubMed
- Laukkanen, J. A., Laukkanen, T., & Kunutsor, S. K. (2018). Cardiovascular and Other Health Benefits of Sauna Bathing: A Review of the Evidence. Mayo Clinic Proceedings, 93(8), 1111–1121. Full text
- Pilch, W., Szyguła, Z., Klimek, A. T., et al. (2014). Effect of a single Finnish sauna session on white blood cell profile and cortisol levels in athletes and non-athletes. Journal of Human Kinetics, 39, 127–135. PubMed
- Hannuksela, M. L., & Ellahham, S. (2001). Benefits and risks of sauna bathing. The American Journal of Medicine, 110(2), 118–126. PubMed
- Singh, M., Singh, M., Jaiswal, N., & Chauhan, A. (2017). Heated, humidified air for the common cold. Cochrane Database of Systematic Reviews. Cochrane
