What to Do in an Infrared Sauna for Best Results

Getting the most out of an infrared sauna comes down to a handful of practical choices: session length, temperature, what you do with your body while you’re in there, how you hydrate, and what you do afterward. Unlike a traditional sauna, which heats the air around you to extreme temperatures, an infrared sauna works at lower air temperatures while warming your tissues more directly. That difference changes the playbook in some surprising ways, and the research on optimizing each variable has grown considerably in recent years.

Set Realistic Expectations for How Deep the Heat Goes

Infrared saunas are often marketed with claims about “deep tissue penetration,” but the actual depth depends on the wavelength and what tissue it’s hitting. Near-infrared radiation penetrates cartilage anywhere from about half a millimeter to 5 mm depending on the spectral range, with the longest wavelengths reaching deepest.¹ In muscle, a recent study found that a single far-infrared session raised superficial muscle temperature by about 3°C, mid-depth muscle by roughly 2°C, and deep muscle by about 1°C, with the effective thermal penetration reaching around 2.4 cm before the warming effect dropped off sharply.²

What this means in practice: the heat is real, and it does warm muscle tissue beneath the skin, but it’s not reaching organs or deep joints the way some marketing implies. The bulk of the effect is in the outer couple of centimeters. That’s still enough to influence blood flow, muscle pliability, and local tissue metabolism, but you shouldn’t expect the infrared to be doing something dramatically different from other forms of heat at the deepest layers of your body.

Temperature and Duration That Actually Move the Needle

Most infrared saunas operate between about 45°C and 65°C (roughly 113–150°F), which feels far milder than the 80°C-plus of a Finnish sauna. That lower air temperature is partly why infrared sessions are tolerable for longer stretches. A well-studied protocol uses 45 minutes at temperatures in the 45–65°C range. At those settings, a study of 20 healthy adults found that core temperature barely budged (rising only about 0.1°C on average), while skin temperature jumped substantially.³ That same study showed far-infrared sauna produced the smallest core temperature increase compared to a traditional sauna or hot water immersion.

If your goal is a meaningful cardiovascular and sweating response without the brutality of extreme heat, 30 to 45 minutes in the 55–65°C range is where most of the research lands. One study using a far-infrared sauna at 65°C found that heart rate climbed from a resting average of about 74 beats per minute to around 153 bpm, and mean arterial pressure dropped after exposure, driven by a fall in diastolic pressure.⁴ That’s a substantial cardiovascular stimulus from sitting still. Other research has compared the heart rate and blood pressure response during sauna bathing to a moderate exercise load of roughly 60 to 100 watts on a bike, with both blood pressure and heart rate climbing progressively during the session and then dropping below baseline afterward.⁵

If you’re new to infrared saunas, start at the lower end of both temperature and time, maybe 15 to 20 minutes at around 50°C, and build up over several sessions. The cardiovascular strain is real even though you’re just sitting there, and people who aren’t heat-adapted can feel lightheaded or nauseous if they jump straight into a long, hot session.

What to Do with Your Body During the Session

Infrared panels emit directional radiant energy, so the side of your body facing the panels absorbs more heat than the side facing away. Many infrared saunas have panels on multiple walls, but if yours concentrates them in one area, rotating your position partway through the session helps distribute the warming more evenly. Sitting upright with your limbs uncrossed and slightly spread exposes more skin surface to the panels than curling into a ball.

There’s a practical case for gentle stretching while you’re inside. The muscle temperature data mentioned earlier showed that superficial muscle warms meaningfully during a session, and warmer muscle tissue is more extensible. Stretching warmed tissue is a long-standing principle in physical therapy. You won’t be able to do anything vigorous in a small sauna cabin, but seated hamstring stretches, neck rolls, shoulder movements, and gentle spinal twists are all feasible and take advantage of the increased tissue temperature. Just keep the movements slow and controlled; your heart rate is already elevated from the heat, so there’s no need to add more cardiovascular demand.

Some people meditate, do breathwork, or simply sit quietly. None of these are going to change the physiological effects of the heat itself, but if relaxation is part of your goal, the sauna environment works well for it. What you probably shouldn’t do is scroll your phone for 40 minutes: the heat and humidity can damage electronics, and the distraction tends to make people ignore early warning signs that they’ve had enough.

Hydration Before, During, and After

You will sweat. A study of healthy adults in a far-infrared sauna found a whole-body sweat rate of about 0.46 liters per hour, with participants losing roughly half a percent of body weight during the session.² That may not sound like much, but it adds up over a 45-minute session, and it’s on top of whatever fluid deficit you walked in with. Research using a portable infrared sauna protocol at around 66°C achieved body-mass losses approaching 2.5 to 3% in healthy young adults through repeated sauna exposures with short rest intervals, which is well into the range where cognitive and physical performance start to suffer.⁶

The practical move is to drink about 500 ml of water in the hour before your session, bring water into the sauna and sip throughout, and drink another 500 ml or so afterward. If your sessions are long or you sweat heavily, adding a pinch of salt or using an electrolyte drink helps replace sodium lost in sweat. The sweat losses aren’t just water; the mineral content can be meaningful over time, particularly if you’re using the sauna frequently.

Using the Sauna After Exercise for Recovery

One of the most evidence-backed uses of an infrared sauna is as a post-workout recovery tool. A study on resistance-trained individuals found that a post-exercise infrared sauna session reduced the drop in explosive performance (measured by countermovement jump height), lowered muscle soreness, and improved perceived recovery compared to a passive rest condition.⁷ If you’re training regularly and can get to a sauna within an hour or so of finishing your workout, the evidence suggests this is worth doing.

A comparison of recovery methods in both athletes and non-athletes found that infrared sauna and warm water immersion were both effective at reducing fatigue markers like blood lactate, and that all thermal modalities lowered blood glucose levels post-exercise. Warm water immersion was the most effective overall for athletes, but infrared sauna and traditional sauna performed better for non-athletes.⁸ If you don’t have easy access to a plunge pool or hot tub, the infrared sauna is a solid alternative for post-exercise recovery.

What to Do After You Step Out

The cool-down period after a sauna session isn’t just about comfort. Research on autonomic nervous system responses found that the cooling-down period after sauna bathing shifted the balance of the autonomic nervous system toward parasympathetic dominance, essentially the “rest and digest” mode. During the session itself, the sympathetic (“fight or flight”) branch dominated, but cooling down reversed that pattern, with vagal tone increasing and sympathetic markers dropping.⁹

This matters because the rebound into parasympathetic activity is likely part of why people feel so relaxed after a sauna. Rushing straight from the sauna into a stressful activity may blunt that response. The Finnish tradition of resting for at least as long as you were in the sauna has some physiological backing here. You don’t need to time it precisely, but give yourself 15 to 30 minutes of calm afterward. A lukewarm (not ice-cold) shower is fine and helps bring skin temperature down gradually. Some people enjoy a cold plunge, but if your main goal is the parasympathetic rebound, a gradual cool-down may be more aligned with that outcome.

Building a Consistent Routine

The stress response to infrared sauna use actually changes over time with repeated exposure. A study tracking female athletes over six weeks of regular post-exercise infrared sauna use found that cortisol levels spiked after the first session but no longer rose after six weeks of consistent use. Heart rate responses also normalized, suggesting the body had adapted to the heat stimulus.¹⁰ This is a heat acclimation effect and mirrors what happens with repeated exercise: the initial stress signal becomes routine, and the body handles it more efficiently.

A three-week program using three sauna sessions per week (nine sessions total, though in a traditional dry sauna at higher temperatures) produced measurable improvements in body composition, flexibility, resting blood pressure, and aerobic capacity in semi-professional football players.¹¹ While that study used much higher temperatures than an infrared sauna provides, it demonstrates the principle that regularity matters more than individual session heroics. Three to four sessions per week appears to be a reasonable frequency for building cumulative benefits, though even two sessions a week will keep you somewhat heat-adapted.

Pain, Stiffness, and Musculoskeletal Conditions

If you’re using an infrared sauna specifically for pain or joint stiffness, the evidence is encouraging but not overwhelming. A systematic review of infrared radiation for musculoskeletal conditions found decreases in pain scores (measured by visual analog scale) across patients with various musculoskeletal disorders, and improvements in fibromyalgia questionnaire scores for people with that diagnosis.¹² A separate review of sauna therapy in rheumatic diseases reported benefits for pain relief, reduced stiffness, and improved mobility in patients with rheumatoid arthritis, ankylosing spondylitis, and osteoarthritis, with some studies showing reductions in inflammatory markers and improved physical function.¹³

For joint-related issues, timing the sauna session before gentle movement or physical therapy may help. The local tissue warming can reduce the perception of stiffness and make joints feel looser. Some physical therapists recommend infrared heat before stretching or manual therapy for this reason. Just be aware that feeling looser doesn’t mean you should push range of motion aggressively; the pain signals that normally keep you from overdoing it may be dulled by the heat.

How Infrared Compares to a Traditional Sauna

If you have access to both types, the choice depends on what you’re after. A head-to-head comparison of healthy adults found that a traditional sauna (three rounds of 10 minutes at 80°C) raised core temperature by about 0.4°C, while a 45-minute far-infrared session at 45–65°C raised core temperature by essentially nothing (about 0.1°C). Heart rate increases were not significantly different between the two modalities, though hot water immersion outpaced both.¹⁴ Mean arterial pressure also didn’t differ between traditional and infrared sauna in that study.

The practical takeaway: if your main goal is raising core temperature (for immune stimulation, for instance), a traditional sauna or hot bath will do more in less time. If you want a substantial cardiovascular stimulus with less perceived discomfort and heat stress, the infrared sauna delivers a comparable heart rate response at temperatures that feel much more tolerable. For recovery and pain relief, both types appear effective, with the infrared sauna’s gentler profile making it easier to use for longer sessions and for people who find extreme heat unpleasant or unsafe.

The “Detox Through Sweat” Question

This is one of the most common claims in infrared sauna marketing, and the truth is more nuanced than either enthusiasts or skeptics usually present. A systematic review found that arsenic, cadmium, lead, and mercury can be excreted in sweat in quantities that sometimes match or exceed urinary excretion over a 24-hour period.¹⁵ A study specifically using a water-filtered infrared sauna found higher concentrations of toxic elements in sweat compared to sweat from conventional exercise or wet sauna, with women showing higher concentrations of toxic elements than men.¹⁶

So the body does excrete some heavy metals in sweat, and infrared sauna-induced sweat may contain meaningful amounts. The caveat is that the total volume of these metals is still tiny in absolute terms, and your liver and kidneys remain the primary detoxification organs by a wide margin. Sweating in a sauna is not going to replace medical chelation therapy for someone with significant heavy metal exposure, and the casual use of “detox” in marketing vastly overstates what the sweat is actually doing. That said, if you view it as a modest supplementary route of excretion rather than a primary detoxification strategy, the evidence does support that something real is happening.

Cardiovascular and Vascular Benefits for People with Heart Conditions

A specific protocol called Waon therapy, developed in Japan, uses far-infrared sauna sessions at 60°C for 15 minutes followed by 30 minutes of bed rest with blankets to sustain the warming effect. A study of patients with chronic heart failure found that three weeks of this protocol improved left ventricular ejection fraction, reduced BNP levels (a marker of heart failure severity), increased six-minute walk distance, and improved flow-mediated dilation of the brachial artery, a measure of vascular endothelial function.¹⁷ Quality-of-life scores also improved.

This is worth knowing because it means infrared saunas aren’t just for healthy people trying to optimize performance. Under medical supervision, they’ve been studied as a therapeutic tool for people with heart failure, a population that can’t tolerate the extreme heat of a traditional sauna. If you have a heart condition, the Waon protocol’s specific parameters (moderate temperature, defined duration, extended post-session rest with blankets) are worth discussing with your cardiologist rather than just winging it with whatever settings your gym’s sauna happens to have.

Skin Effects Over Repeated Use

Infrared radiation’s effects on skin are a mixed bag. A study examining both fibroblast cultures and clinical outcomes found that infrared exposure increased collagen and elastin production in proportion to the duration of exposure, and that after six months of infrared treatment, patients reported substantial improvements in skin texture and roughness.¹⁸ That sounds like good news for regular sauna users, but it’s worth noting that the therapeutic infrared devices used in dermatology studies are calibrated differently from consumer saunas. The wavelength, intensity, and exposure pattern matter, and it’s not clear that sitting in a commercial infrared sauna replicates the conditions that produced those skin improvements.

On the flip side, prolonged repeated heat exposure to the skin can cause a condition called erythema ab igne, a mottled, discolored rash that develops on areas chronically exposed to heat sources. This is more commonly associated with heating pads and laptop use than with saunas, but anyone using an infrared sauna daily should be aware of it, particularly if they always sit with the same skin area facing the heating panels. Rotating your position, as mentioned earlier, helps here too.

Who Should Be Cautious

The cardiovascular strain of an infrared sauna session is real, even if it feels gentler than a traditional sauna. People with uncontrolled high blood pressure, unstable angina, or recent heart attack should get medical clearance first. Pregnant women are generally advised to avoid sustained core temperature elevation, though infrared saunas’ minimal effect on core temperature makes this less clear-cut than with traditional saunas or hot tubs. The conservative advice is still to avoid it or keep sessions very short.

Alcohol and saunas are a bad combination. Alcohol impairs thermoregulation, blunts the thirst response, and is associated with a substantial share of sauna-related sudden deaths in epidemiological data from Finland. The same applies to infrared saunas, even though the air temperature is lower. If you’ve been drinking, skip the session. People taking medications that affect blood pressure, heart rate, or sweating (including beta-blockers, diuretics, and some antihistamines) should also check with their prescriber, since the sauna’s effects on heart rate and fluid balance can interact with these drugs in unpredictable ways.

Anyone with multiple sclerosis or other conditions that worsen with heat should approach infrared saunas very cautiously. The lower air temperature doesn’t eliminate the risk, because the radiant heat still warms tissues. Starting with a very short session at low temperature and having someone nearby in case of symptoms is a reasonable precaution if you want to try it at all.