Can Infrared Sauna Help Rheumatoid Arthritis and Ankylosing Spondylitis? An Early Pilot Study

People with inflammatory joint conditions are often told to avoid heat during flares, so a study specifically testing whether infrared sauna is safe and helpful for these conditions is worth including — with its limitations clearly stated.

What the research looked at

Published in Clinical Rheumatology in 2009, this pilot study enrolled 17 patients with rheumatoid arthritis and 17 patients with ankylosing spondylitis. Over four weeks, participants received eight infrared sauna sessions. Researchers tracked pain, stiffness, and fatigue both during individual sessions and across the full four-week period, along with any signs of disease flare-up.

What they found

During individual sauna sessions, pain and stiffness decreased significantly in both groups. Fatigue also decreased. Across the full four-week treatment period, pain, stiffness, and fatigue showed clinical improvement, though these longer-term changes weren't statistically significant. Importantly, the therapy was well tolerated, with no reported adverse effects and no disease flare-ups in either group.

What this means in practice

This is a small, uncontrolled pilot study (34 patients total, no placebo comparison group), so the improvements can't be fully separated from natural fluctuation in symptoms or a placebo-like response to a pleasant, relaxing treatment. What it does establish reasonably well is safety — infrared sauna didn't trigger flare-ups in either inflammatory condition, which is a meaningful finding given that heat is sometimes assumed to be risky for these patients. Anyone with rheumatoid arthritis or ankylosing spondylitis should still check with their rheumatologist before starting regular sauna use, particularly during active flares.