Regular sauna use does appear to reduce chronic inflammation over time. A long-term study from the University of Eastern Finland found that people who used a sauna four to seven times per week had significantly lower levels of C-reactive protein (CRP), a key marker of systemic inflammation, compared to those who went just once a week. The relationship is dose-dependent: more frequent sessions are linked to greater reductions in inflammatory markers.
That said, the picture is more nuanced than “sauna equals less inflammation.” A single session can temporarily raise certain inflammatory signals, and the type of sauna, how long you stay, and your underlying health all shape whether the experience helps or harms.
What Happens to Inflammation During a Session
When you sit in a sauna, your core body temperature rises, and your body mounts a stress response similar to moderate exercise. Part of that response involves a short-term increase in interleukin-6 (IL-6), a signaling molecule that plays a dual role in inflammation. In the short term, IL-6 spikes tell the body to ramp up repair and immune activity. A study in healthy adults found that a longer Finnish sauna session (two rounds of 10 minutes at about 176°F) raised IL-6 levels, while a single 10-minute round did not produce a meaningful change.
At the same time, sauna exposure triggers the release of an anti-inflammatory counterpart called IL-1 receptor antagonist, which blocks one of the body’s key inflammation pathways. Both short and longer sauna sessions increased this protective molecule. CRP, however, did not change after a single session in either direction. This tells us something important: one sauna visit won’t lower your baseline inflammation. The benefits come from repeating that controlled heat stress over weeks and months, training the body to dial down its inflammatory set point.
Long-Term Effects on Inflammatory Markers
The strongest evidence for sauna’s anti-inflammatory benefits comes from the KIHD cohort study, which tracked Finnish men over more than a decade. Compared to men who used a sauna once a week, those who went two to three times per week had CRP levels about 0.68 mg/L lower after adjusting for other health factors. Men who went four to seven times per week saw an even larger drop of 0.84 mg/L. Over 11 years of follow-up, those reductions grew: the most frequent sauna users experienced CRP declines of roughly 1.66 mg/L compared to the once-a-week group.
To put that in perspective, CRP above 3.0 mg/L is generally considered high risk for cardiovascular problems, and reductions of this size can move someone from a higher risk category to a lower one. This pattern mirrors what researchers see with regular exercise: repeated bouts of short-term physiological stress lead to a lower resting state of inflammation.
Infrared vs. Traditional Finnish Saunas
Not all saunas produce the same physiological response. Traditional Finnish saunas operate at 150 to 195°F with low humidity and raise core body temperature more effectively than infrared alternatives. Far-infrared saunas, which use radiant heat panels at lower temperatures (typically 120 to 150°F), are the least effective at raising core temperature and produce weaker cardiovascular and immune responses in head-to-head comparisons.
That doesn’t mean infrared saunas are useless. Their gentler heat may benefit people with joint conditions like rheumatoid arthritis, where the goal is localized pain relief rather than a full systemic heat stress response. Infrared heat penetrates tissue and increases blood flow to joints, helping deliver oxygen-rich blood that clears away inflammatory byproducts. For people who find traditional saunas too intense, infrared versions offer a more tolerable entry point. But if your goal is to lower system-wide inflammatory markers like CRP, the existing research more strongly supports traditional saunas at higher temperatures.
Benefits for Joint Pain and Arthritis
People with rheumatoid arthritis and similar inflammatory joint conditions often report meaningful symptom relief from regular sauna use. The mechanism is straightforward: heat dilates blood vessels and increases circulation to inflamed joints, reducing the oxygen-starved environment that worsens swelling. This improved blood flow helps flush out reactive oxygen species, the molecular debris that accumulates during chronic inflammation and restricts joint movement.
There’s also a neurological component. Repeated heat exposure can recalibrate the body’s stress response, effectively turning down the volume on pain signaling. Over time, some people with chronic inflammatory conditions find that they perceive the discomfort from their condition less acutely. However, it’s worth noting that people with rheumatoid arthritis, ankylosing spondylitis, and chronic pain conditions also tend to report greater heat intolerance, so starting with shorter sessions is particularly important for this group.
How Often and How Long
The inflammatory marker data points toward a clear threshold: two to three sessions per week is where measurable benefits begin, and four or more sessions per week produces the largest reductions. Each session should last roughly 15 to 20 minutes for someone with experience. If you’re new to saunas, start with 5 to 10 minutes and gradually increase. Most guidance caps sessions at 20 to 30 minutes regardless of experience level.
Temperature matters too. Traditional Finnish saunas typically run between 150 and 195°F. The studies showing the strongest anti-inflammatory effects used temperatures around 176°F (80°C). You don’t need to push to the extreme end of the range to get results, and going above 212°F is not recommended in any setting.
Who Should Be Cautious
Sauna use is safe for most healthy people, but certain conditions change the calculus. If you have cardiovascular disease, uncontrolled high blood pressure, a seizure disorder, or diabetes, sessions should be limited to 5 to 10 minutes. People with unstable coronary artery disease face a real risk of reduced blood flow to the heart during heat exposure. Those with asthma, COPD, or kidney disease may also find that high heat worsens their symptoms.
The combination of sauna and sudden cold exposure (like a cold plunge) creates additional strain on the cardiovascular system. If you have a heart condition or high blood pressure, skip the abrupt temperature swings. Alcohol, sedating medications, and anything that interferes with your body’s ability to regulate temperature should be avoided before and during sauna use. Rare but serious adverse events, including heatstroke and a condition sometimes called “sauna lung” from inhaling contaminated steam, have been documented.
Perhaps counterintuitively, people with the inflammatory conditions most likely to benefit from sauna therapy, such as rheumatoid arthritis and chronic fatigue syndrome, are also the ones most prone to heat intolerance. If you fall into this category, starting very conservatively and paying close attention to how you feel during and after sessions is the safest approach.