Short answer: warmth can help stiff joints and tight muscles feel better for a while, and a small study found that infrared sauna sessions eased pain and stiffness in people with rheumatoid arthritis and ankylosing spondylitis during treatment. But the evidence is limited, a sauna doesn't treat the disease or reduce joint damage, and heat can feel worse during a flare. Think of it as a comfort measure alongside your treatment plan, not a replacement for it.
This article is general information, not medical advice.
Arthritis in Brief
Arthritis means inflammation or swelling of the joints, and the CDC notes that it covers more than 100 conditions. Two common ones are:
Osteoarthritis (OA): the cartilage that cushions the ends of bones breaks down over time, causing pain and stiffness.
Rheumatoid arthritis (RA): an autoimmune disease in which the immune system attacks the lining of the joints, causing inflammation, pain and swelling.
Because the causes differ, your best plan depends on your type of arthritis and your doctor's advice.
What the Research Shows
The main infrared sauna study: in a 2009 pilot study in Clinical Rheumatology, 17 people with rheumatoid arthritis and 17 with ankylosing spondylitis had eight infrared sauna sessions over four weeks. Pain and stiffness dropped significantly during sessions, and fatigue also eased. Over the four weeks, improvements were noticeable but not statistically significant. Sessions were well tolerated and didn't worsen disease activity. It was small and had no comparison group.
Heat for osteoarthritis: the 2019 American College of Rheumatology and Arthritis Foundation guideline gives a conditional recommendation for thermal treatments (heat or cold) for OA of the hand, hip and knee. It strongly recommends exercise, tai chi, weight loss where needed and self-management programs. That guideline is about heat in general, not saunas specifically.
What heat doesn't do: no good studies show that a sauna reduces joint inflammation, repairs cartilage or changes the course of arthritis. Claims that infrared heat lowers inflammatory proteins or "heals" joints aren't backed by reliable evidence.
For more on what sauna research does and doesn't support, see our guide to infrared sauna benefits and our post on infrared saunas and joint pain.
Heat or Cold? When to Skip the Sauna
Many people with arthritis find warmth soothing for everyday stiffness, especially in the morning or before gentle exercise. But if a joint is hot, red and swollen, as in a flare or after an injury, heat may make it feel worse. Many people use a cold pack in those moments instead. If you're not sure whether you're having a flare, ask your doctor before using a sauna.
How to Use an Infrared Sauna Safely With Arthritis
| Step | What to do |
|---|---|
| Get the OK | Check with your doctor first, especially if you have heart problems, high or low blood pressure, or take medicines that affect blood pressure or sweating. |
| Start cool and short | Set the sauna to about 120°F and start with 10 minutes. Harvard Health advises no more than 15 to 20 minutes per session. |
| Hydrate | Drink water before and after your session. |
| Protect your skin | Sit on a towel and keep a towel under your feet. Take extra care if you have numb skin, since you may not feel a burn. |
| Move carefully | Stiff joints and a light-headed feeling don't mix. Use a handrail or a steady hand when getting in and out, and stand up slowly. |
| Follow with gentle movement | Some people like to stretch or do range-of-motion exercises while their joints feel warm. |
Our sauna session time guide and first-timer's guide cover the basics, and our guide on what to wear in a sauna helps with comfort.
Arthritis Medicines and Heat
The CDC notes that NSAIDs (such as ibuprofen and naproxen) are linked to kidney injury when combined with dehydration. If you take NSAIDs regularly, keep sessions short, drink water and ask your doctor or pharmacist whether sauna use is OK for you.
Who Should Check With a Doctor First
People with heart disease or uncontrolled high blood pressure
People with low blood pressure or who often feel faint
Anyone who is pregnant
People with nerve damage or numb skin (see our post on saunas and nerve pain)
Anyone with a fever or infection, or a hot, swollen joint
Never use a sauna after drinking alcohol.
What Helps Arthritis Most
The CDC says physical activity can help people with arthritis reduce joint pain and improve function and mood, and that it's safe for people with arthritis. It recommends:
At least 150 minutes a week of moderate activity, such as brisk walking, cycling or swimming
Muscle-strengthening activities on at least 2 days a week
Starting slowly; even 5 or 10 minutes at a time helps
Keep following the treatment plan from your doctor, and ask about a physical therapist if you'd like help getting started. A warm, relaxing sauna session can fit around this as a comfort habit.
The Bottom Line
An infrared sauna can make stiff joints feel better for a while, and a small study found it was well tolerated by people with RA and ankylosing spondylitis. It doesn't treat arthritis itself. Skip it during a hot, swollen flare, keep sessions short and cool, stay hydrated, and talk to your doctor first.
