Infrared and heat: what does the research really say?
Search for infrared and you get two extremes. On one side, pages claiming that half an hour of heat detoxes you, burns six hundred calories and heals your joints. On the other, people saying it is all nonsense. Neither is right, and the difference lies in the research that actually exists.
This page is our evidence base. For each use, it shows what was studied, how many people took part, what came out of it and how solid that is. Including the studies that found nothing, because they belong here just as much. We sell infrared products, so you are welcome to check us on this: every source is listed with a link to the original publication.
How to read research on heat
Before you dive into the results, here are three things that make the difference between a strong and a weak finding in heat research.
Blinding is almost impossible. With a pill, the control group gets a placebo and nobody knows who got what. With heat, every participant knows whether they are lying somewhere warm or not. Anything measured with a questionnaire, and pain is nearly always a questionnaire, therefore contains a share of expectation. Studies that solve this with a sham treatment are rare and carry more weight.
During is not the same as after. Many studies measure an improvement during or just after a session. That is a real effect, but it is comfort, not treatment. The question that matters is whether anything is left after four weeks, and that is exactly where most studies drop off.
The device decides whether a result carries over. The word infrared covers devices that technically have little in common. A result from one device says little about another.
| Device in the research | What it is | Comparable to a sauna blanket? |
|---|---|---|
| Infrared cabin | Cabin with emitters, 55 to 60 °C, air can circulate | Partly: same wavelength range, different heat dissipation and no skin contact |
| Finnish sauna | Hot air of 80 to 100 °C, no infrared emitters | No, a different mechanism and a much higher temperature |
| Light therapy device | LEDs or lasers, for example 890 nanometres, hardly any heat | No, that is light, not heat |
| Ceramic patch or clothing | Passive material that reflects body heat | No, no heat source of its own |
| Medical hyperthermia | Clinical installation that raises core temperature in a targeted way | No, that is a treatment device in a hospital |
| Heat pack or heat wrap | Conductive heat directly on the skin | Partly: also skin contact, but on a small area |
Remember that table, because it explains nine out of ten exaggerated claims. Someone finds an effect with a ceramic patch on a knee, and it gets quoted as proof for a blanket. The background on wavelengths is in far infrared versus near infrared and in wavelengths of red light and infrared. What an infrared sauna is exactly and how the three forms relate to each other is explained in what is an infrared sauna.
Five devices, one word. That is where nearly every inflated claim about infrared begins.
Pain and stiffness in rheumatic conditions
This is what most people search for, and it is a good example straight away of how carefully you need to read.
The best known study is Dutch. Researchers had 34 patients, 17 with rheumatoid arthritis and 17 with ankylosing spondylitis, do eight sessions of thirty minutes in an infrared cabin at 55 °C, spread over four weeks. During and directly after a session, pain and stiffness fell by a statistically significant amount, with p below 0.05 for rheumatoid arthritis and p below 0.001 for ankylosing spondylitis. Over the full four weeks there was an improvement, but it did not reach statistical significance; stiffness in rheumatoid arthritis came closest with p equal to 0.06. The sessions were well tolerated, 88 percent felt comfortable or very comfortable afterwards, and the disease did not flare up.
The authors therefore call their own finding "a trend towards long-term beneficial effects" and write that further research needs at least 25 patients per group. There was also no control group during the treatment weeks.
It was shown that pain and stiffness decreased during the session. It was not shown that the condition itself was affected or that the effect lasted. That difference is exactly what adverts skip over.
Fibromyalgia
Here two studies of very different quality sit side by side, and the contrast is instructive.
The first is Japanese, using Waon therapy: fifteen minutes in a far infrared cabin at 60 °C, followed by thirty minutes of keeping warm under a blanket. Thirteen women, no control group, not blinded. Pain roughly halved after the first session and stabilised after ten treatments, with p below 0.01. Impressive numbers, but with a subjective pain score and no control group, you are also measuring expectation and the natural course of things.
The second is German and far more robust: a randomised study with a sham treatment as control. 41 participants, six treatments in three weeks with water filtered infrared A whole body hyperthermia. Pain intensity in week four differed significantly between the groups in favour of the heat group, with p equal to 0.015. The drop was 1.7 points on a scale of 0 to 10, roughly 31 percent.
Put the two side by side and you see what blinding does: from roughly 50 to 78 percent less pain without a control to roughly 31 percent with one. The effect has not gone, it is smaller. And the device in the strongest study was a medical installation, not a consumer product.
Chronic pain
A Japanese study followed 46 inpatients with chronic pain for two years. Everyone received a complete multidisciplinary programme with cognitive behavioural therapy, rehabilitation and exercise therapy. Half also received infrared heat every day for four weeks on top of that. Both groups improved significantly in pain, pain behaviour and mood. The most striking difference was in returning to work: 17 of 22 in the heat group were working again after two years, against 12 of 24 in the control group, with p below 0.05.
What you cannot take from this is the effect of the heat alone. The heat came on top of a full treatment programme in a hospital, and the control group improved too.
Muscle soreness after exercise
This is the area with the most studies and the least favourable outcome for infrared.
A meta analysis of 32 randomised studies with 1,098 participants looked at heat and cold for muscle soreness after exertion. Heat reduced the pain, both within 24 hours and afterwards. But when you split it by type of heat, almost the entire effect comes from the heat pack. About the other forms of heat, the authors write literally that they were not statistically significant.
The systematic review on infrared for musculoskeletal conditions is even more direct: infrared failed to aid recovery after sports injuries. And a 2025 umbrella review that summarised 29 reviews and 863 randomised studies did give heat therapy a large point estimate, but placed the evidence in the weakest category, noting that 17 of the 29 underlying reviews were of critically low methodological quality.
| Use | Best evidence | How strong |
|---|---|---|
| Muscle soreness after exercise, heat pack | Meta analysis of 32 studies | Reasonable, but with wide confidence intervals |
| Muscle soreness after exercise, infrared | Systematic review | No proven effect |
| Recovery after sports injury, infrared | Systematic review | Explicitly negative |
Lower back pain
The Cochrane review on superficial heat for lower back pain covers nine studies with 1,117 participants. A heat wrap reduced pain significantly after five days compared with a placebo pill, and a heated blanket lowered acute back pain directly after use. The reviewers' conclusion is sober: moderate evidence from a small number of studies for a small, short lived effect, and better studies are needed.
Two notes that really matter. This was conductive heat, so wraps and blankets, not infrared radiation. And the effect applied to acute and subacute back pain, not chronic. The review has also not been updated since 2006.
Knee osteoarthritis
Here two studies contradict each other, and the stronger of the two is negative.
The positive study used an infrared emitting patch in 60 participants, single blind, and found a significantly lower pain score after one week and after one month. The negative study was randomised, double blind and placebo controlled, with 73 participants and six forty minute sessions using an 890 nanometre light therapy device. No significant difference was found on any outcome measure. Those authors conclude that short term therapy brought no benefit for body functions, activities, participation or quality of life.
Heart and blood vessels
This is the area with the biggest numbers and at the same time the biggest chance of a wrong conclusion.
The Finnish cohort studies
A large population study has been running in eastern Finland since the 1980s. Among 2,315 men followed for twenty years, those who used the sauna four to seven times a week had a lower risk of sudden cardiac death than men who went once a week: hazard ratio 0.37 with a confidence interval of 0.18 to 0.75. For all cause mortality it was 0.60. Later publications from the same cohort found similar patterns for high blood pressure and stroke.
Those are big numbers, and they come with four serious catches.
- It is observational. Anyone who can go to the sauna four times a week is usually already healthy enough to do so. The authors themselves write that residual confounding remains possible and name reverse causation as a limitation.
- Sauna frequency was asked once, at the start, with a questionnaire, and then not measured again for twenty years.
- The most favourable group was small: 201 men out of 2,315. Hence that wide interval of 0.18 to 0.75.
- It is about the Finnish sauna. The authors state in their own publications that the findings do not apply to other forms of passive heat, and not to steam rooms or hot water therapy.
Two independent research groups also published criticism in the same journal, under the heading that the link between sauna use and mortality may not be causal. That is not a side note, it is the heart of the debate.
Infrared for heart failure
The only infrared specific research in this area comes from Japan, with the Waon protocol: fifteen minutes at 60 °C, followed by thirty minutes of bed rest under a blanket, in inpatients with heart failure. Smaller studies showed improvement in vascular function and heart failure markers. A comparative study over five years found fewer cardiac events in the treated group.
But the best designed study in that series, a multicentre randomised trial with 149 patients in 19 centres, missed its primary endpoint: the change in BNP did not reach statistical significance. The positive results there were secondary and within group. A randomised study that misses its primary endpoint is a negative study.
Blood pressure and vascular function
The most convincing experimental work used not a sauna but hot water immersion. Twenty young, healthy and inactive participants, eight weeks of four to five sessions a week in which core temperature was held at 38.5 to 39 °C for sixty minutes. Vasodilation improved from 5.6 to 10.9 percent, arterial stiffness fell and mean blood pressure dropped by five millimetres of mercury. In the sham group nothing changed. Ten people per group, no randomisation but matching.
A meta analysis of fifteen studies on passive heat therapy found an average drop in arterial pressure of almost six millimetres of mercury and an improvement in vasodilation of almost two percent. That is a real effect, but the studies vary widely and it concerns heat therapy in the broad sense, not a blanket at home.
How solid is this evidence, really?
One review assessed this formally. Of 40 clinical studies with 3,855 participants, 13 were randomised, and of those only three had a low risk of bias. Nine of those thirteen had fewer than fifty participants. That is the honest state of the field.
Sleep
The strongest line of evidence here is not about infrared. A meta analysis of thirteen studies on passive body heating found that water at 40 to 42.5 °C, one to two hours before bedtime, was linked to better perceived sleep quality, higher sleep efficiency and falling asleep faster, in the order of about ten minutes.
A newer meta analysis of ten randomised studies is more critical: total sleep time and sleep efficiency improved significantly, but time to fall asleep did not, and no effect was found on perceived sleep quality. The authors conclude that the sleep promoting effect has its limits.
All the studies above used a warm bath or shower. There is no randomised study with objective sleep measurement that links sauna or infrared heat to better sleep. In a questionnaire survey of 482 sauna users, 83.5 percent reported sleep benefits, but that is self reporting by people who choose to go to the sauna.
What we take from this for an evening ritual with heat: the idea of warming up and then cooling down before bed has a plausible basis, and the timing of one to two hours beforehand comes from that research. It is no more than that.
What the research actually disproves
Detoxing
An extensive physiological review of sweat glands is explicit: the role of sweating in excreting waste products and toxic substances is small compared with the kidneys and the gastrointestinal tract. Sweat glands cannot step up their excretion the way a kidney can.
There is one review that did find measurable amounts of heavy metals in sweat, and the industry likes to quote it. But the same physiological review points out the methodological problem: sweat collected from the skin also contains sebum, skin cells and residue from outside, which artificially raises the measured concentrations. And the authors of that first review themselves call for trials to establish whether there is any clinical benefit. Those trials do not exist.
Weight loss
A study of 674 people after two ten minute sauna sessions showed weight loss that was greater at a higher BMI, and the authors explicitly treat it as fluid loss that needs rehydration. An experimental study in 22 women measured a loss of 0.14 kilos after twenty minutes at 80 °C and 0.30 kilos at 120 °C. That is fluid, and it comes back as soon as you drink.
The same study estimated energy expenditure at 119 and 186 kilocalories, but that estimate comes from a heart rate monitor, not from calorimetry. With passive heat, heart rate rises sharply without oxygen consumption rising to match, so that figure is almost certainly too high. That is why we do not use it as a sales argument.
Cholesterol
A review of far infrared saunas assessed nine studies and concluded that there is consistent fair evidence to actually refute claims of lower cholesterol. That is the rare case where a claim is not merely unproven, but has been actively studied and does not hold up.
And the sauna blanket itself?
This is the question we would most like to skip, and precisely the one we do not skip. Of all the studies above, not a single one used a sauna blanket. Not one.
There is exactly one publication in which an infrared sauna blanket is the device studied. Eight participants, twenty years old on average, in a randomised crossover: sixty minutes in a blanket at about 75 °C against the same blanket switched off. Temperature under the tongue rose from 36.8 to 38.2 °C, with no change in the control condition. Sweat loss was 1.3 against 0.3 litres, but that difference was not statistically significant. At the end, participants gave the highest score for thermal discomfort.
Not a single measure of pain, stiffness or recovery was taken, it was one session, and it is a conference abstract, not a full peer reviewed paper. The authors' conclusion is modest and honest: the blanket produces a thermal response comparable to traditional heat sources, which makes it interesting for future research into heat therapy at home.
For the sauna blanket there is one study with eight participants, and it shows that you get warm in it. Nothing more.
So what follows from that? That a sauna blanket does what a heat source does: it warms you up, makes you sweat and lets you lie still for half an hour. That the clinical results from cabins, patches and hospital equipment simply apply to it does not follow. So we do not take that step, even when competitors do.
Safety: what is well supported
Interestingly, on some points the evidence about risks is stronger than the evidence about benefits.
| Topic | What the research shows | What you do with it |
|---|---|---|
| Alcohol | Of 103 deaths in Korean saunas, 78.6 percent had alcohol in their blood, 73.8 percent above the intoxication threshold. The authors name alcohol as the most important risk factor | Never a session after alcohol, not even after one glass |
| Pregnancy | A meta analysis links raised body temperature in early pregnancy to a higher risk of neural tube defects. The NHS advises avoiding saunas and hot tubs because of overheating, dehydration and fainting | Do not use, and ask your midwife |
| Medication | A meta analysis of 35 studies found that strongly anticholinergic drugs raise core temperature in heat by 0.42 °C, adrenaline by 0.41 and nonselective beta blockers by 0.11. A review classified 110 medicines with strong evidence of increased heat vulnerability, of which 127 drugs act through reduced sweating | If you take medication, ask your pharmacist or doctor |
| Heart and vascular disease | One review lists situations in which heat should be avoided, including infectious diseases, acute chest pain, unstable angina, decompensated heart failure and severe aortic valve stenosis. Blood pressure medication taken just before a session can encourage orthostatic hypotension | Talk to your doctor and do not take your medication just beforehand |
| High temperatures | In a study of 22 women, three participants fainted at 120 °C. The authors advise occasional sauna users against 120 °C | Starting gently works better than starting high |
| Dehydration | A weight loss of 0.14 to 0.30 kilos per session is fluid, and people with a higher BMI in particular lose more | Drink before, during and after |
What that means in practice is covered in the safety guide for sauna blankets, in drinking around your session and in signs that a session was too long or too hot.
The risk that belongs to blankets specifically
There is one hard, documented fact about sauna blankets as a product category, and it is not about a benefit. In October 2025, the US product safety authority recalled around 78,000 infrared sauna blankets from one manufacturer because of overheating, after 65 reports, 32 of which involved burns.
That says nothing about other brands, and that is exactly why it matters: with a device you close around yourself and that lies directly against your skin, build quality is not a detail. What to look for, whatever the brand:
- Automatic shut off and overheating protection, and not just as a word in the advert but in the manual.
- A timer that limits the session, so dozing off does not become a risk.
- A manufacturer that tells you who tested the product, not just that it was tested.
- A real power rating in the specifications, not a marketing number.
Luxyor has its products assessed by an independent testing body that we hire but that reaches its own judgement. What comes out of that and how it works is on product testing and transparency.
The sources at a glance
Every study this page relies on, with a link to the original publication. Check them, that is exactly why they are here.
| Topic | Publication | Design and size |
|---|---|---|
| Rheumatism and spondylitis | Oosterveld et al., Clinical Rheumatology | Pilot, 34 patients, infrared cabin |
| Fibromyalgia, uncontrolled | Matsushita et al., Internal Medicine | Open label, 13 women, Waon |
| Fibromyalgia, with sham treatment | Langhorst et al., Journal of Clinical Medicine | Randomised, 41 participants, medical hyperthermia |
| Chronic pain | Masuda et al., Psychotherapy and Psychosomatics | 46 inpatients, heat on top of a programme |
| Infrared for the musculoskeletal system | Tsagkaris et al., EJIHPE | Systematic review, 13 studies, five device types |
| Muscle soreness after exercise | Wang et al., Physical Therapy in Sport | Meta analysis, 32 studies, 1,098 participants |
| Muscle soreness, overarching | Wiecha et al., Sports Medicine | Umbrella review, 29 reviews, 863 studies |
| Lower back pain | French et al., Cochrane | 9 studies, 1,117 participants, heat wrap |
| Knee osteoarthritis, positive | Bagnato et al., Reumatismo | Single blind randomised, 60 participants, patch |
| Knee osteoarthritis, negative | Hsieh et al., JOSPT | Double blind randomised, 73 participants, 890 nm |
| Sauna and mortality | Laukkanen et al., JAMA Internal Medicine | Cohort, 2,315 men, 20 years, Finnish sauna |
| Criticism of that cohort data | Kivimäki et al., JAMA Internal Medicine | Letter to the editor, possibly not causal |
| Infrared for heart failure | Tei et al., Circulation Journal, WAON CHF | Randomised, 149 patients, primary endpoint not met |
| Vascular function | Brunt et al., The Journal of Physiology | 20 participants, 8 weeks, hot water immersion |
| Quality of the sauna evidence | Hussain and Cohen, eCAM | 40 studies, 3,855 participants, 13 randomised |
| Infrared sauna, claims tested | Beever, Canadian Family Physician | Review, 9 studies, cholesterol claim refuted |
| Heat and sleep | Haghayegh et al., Sleep Medicine Reviews | Meta analysis, 13 studies, warm bath |
| Sweating and excretion | Baker, Temperature | Physiological review of sweat gland function |
| Medication and heat | Hospers et al., eClinicalMedicine | Meta analysis, 35 studies, 27 medicines |
| Alcohol and sauna | Yang et al., Forensic Science, Medicine and Pathology | 103 deaths, forensic analysis |
| Sauna blanket as a device | Nicolet et al., IJES Conference Proceedings | Conference abstract, 8 participants, one session |
Judging a claim yourself
You do not need to be a researcher to weigh up a product claim. Six questions filter out most of the nonsense.
- Which device was studied? A cabin, a patch, a light therapy device and a blanket are not interchangeable.
- Was there a control group? Without one, with pain you mainly measure expectation.
- Was it measured during or after the treatment period? Improvement during the session is comfort, not treatment.
- How many participants? Under fifty, it is a hint, not a conclusion.
- Is there a source you can open? A claim without a clickable source is an opinion.
- Would the same claim also hold for a warm bath? If so, it says nothing about infrared in particular.
A seller who is honest about what a device does not do is usually reliable about what it does do as well. If the downsides are missing entirely from a product description, that in itself tells you something.
What this means for each product
Below, per type of product, what you can reasonably expect based on all of the above, and what you should not expect. None of these products is a medical device.
Infrared sauna blanket
What is certain: it makes you warm, your core temperature rises, you sweat and you lie still for half an hour. That is exactly what the only blanket study measured. What does not follow: clinical results from cabin studies, patches or hospital equipment. What people mention in practice as their reason to make it a habit is the moment of rest itself and the warm feeling.
If you are choosing one, have a look at the buying guide with checklist and at materials, finish and quality.
- Far infrared across the entire inner surface of 180 × 80 cm
- Adjustable from 30 to 80 °C, with a timer up to 60 minutes and automatic shut off
- 60 days to change your mind and a 2 year warranty
Want more room or a different finish? The Comfort 150 and the Deluxe 310 work on the same principle and differ in fabric, zips and finish. The comparison is in Slimline, Comfort or Deluxe.
Infrared lamp
A lamp gives targeted heat on one spot. The most transferable research here is on superficial heat, and that is about heat wraps and heated blankets: a small, short lived effect for acute complaints. So what you can expect from a lamp is warmth on the spot you aim it at, for as long as it is on.
Distance and time determine the intensity, not the wattage on the box. That is explained in distance and duration with an infrared lamp.
- 275 W heat lamp for targeted use on one spot
- Also available separately as the Redlight 160 on a mobile stand
- 60 days to change your mind and a 2 year warranty
Red light panel and LED mask
This is a different field with different literature. Red light and near infrared work through light, not heat, and the research on them is separate from everything on this page. We have a separate evidence page for that: red light therapy, what does the research really say, with the dose in joules per square centimetre, the wavelengths and the same honest limitations.
Take a look at the red light panels and masks if that is the direction you are leaning.
Infrared brace
A brace sits snugly around a knee, elbow or wrist and gives off heat there. In terms of how it works, it is closest to the heat wrap from the Cochrane review, which also makes that the most transferable research there is: a small and short lived effect for acute complaints. Expect warmth and support, not treatment.
- For knee, elbow or wrist, with adjustable settings
- Aimed at one joint instead of your whole body
- 60 days to change your mind and a 2 year warranty
Further reading in the knowledge base
This page is the evidence base. The practical side is spread across the knowledge base and the articles.
| You want to know | Then read |
|---|---|
| How infrared heat works technically | How infrared heat works exactly |
| What an infrared sauna is exactly | What is an infrared sauna |
| Everything about sauna blankets in one place | Knowledge base infrared sauna blankets |
| Everything about red light therapy | Knowledge base red light therapy |
| When a blanket is less suitable | When is a sauna blanket less suitable |
| What the research says about red light | Red light therapy, what does the research really say |
| What heat does to your circulation | Infrared and circulation |
| How often and how long to do a session | Weekly schedule for infrared and red light |
| How independent testing works at Luxyor | Product testing and transparency |
To sum up
The honest answer to whether infrared works is that it depends on what you mean by works. That heat can reduce pain and stiffness during and shortly after a session has been found in several small studies, and in fibromyalgia even in a study with a sham treatment. That infrared treats a condition, that effects last, or that it speeds up muscle recovery has not been shown, and on that last point it has even been refuted. And about the sauna blanket specifically, nothing more is known than that it makes you warm.
For us, that is enough to sell a product people happily spend half an hour in. It is not enough to attach a health promise to it, so we do not. If you come across a seller who does, ask for the study. It is the quickest test there is.
Browse the Luxyor infrared sauna blankets or read on in the knowledge base.
Frequently asked questions
Is infrared scientifically proven?
Partly. That heat can reduce pain and stiffness during and shortly after a session has been found in several small studies, including a randomised study with a sham treatment in fibromyalgia. That infrared treats a condition, or that effects last, has not been shown.
Is there research on infrared sauna blankets?
One publication, a conference abstract with eight participants and one session. It shows that your core temperature rises and that you sweat. Pain, stiffness or recovery were not measured. All clinical studies used cabins, patches, light therapy devices or hospital equipment.
Does infrared help with muscle soreness after exercise?
The research actually points the other way. In a meta analysis of 32 studies, the effect came almost entirely from heat packs, and a systematic review concluded that infrared did not aid recovery after sports injuries.
Do the Finnish sauna studies also apply to an infrared cabin or blanket?
No. Those figures come from Finnish saunas at 80 to 100 °C, and the researchers themselves write that their findings do not apply to other forms of passive heat. They are also observational studies, so not proof of cause and effect.
Do you detox by sweating in a sauna blanket?
No. An extensive physiological review states that the role of sweating in excreting waste products is small compared with the kidneys and the gastrointestinal tract. Sweat consists mainly of water and salt.
Do you lose weight from a session?
The weight you lose is fluid, in the order of 0.14 to 0.30 kilos per twenty minutes, and it comes back as soon as you drink. The calorie estimates from sauna studies come from heart rate monitors, not from calorimetry, and are almost certainly too high.
