Infrared Light: is it safe or dangerous?

Whether from the sun, fire, electric lights or light-emitting diodes (LEDs), people have never known a world without infrared radiation (IR). It toasts your bread, changes the channel on the TV and bakes the paint on a new car. On the downside, you cannot see IR, and it travels only in straight lines.

Humans are inundated with light waves every second of every day. There's the light we think about — visible light pouring forth from the sun and electric light bulbs and ultraviolet (UV) light that turns our skin red, tan, and eventually wrinkled. And there's the light we don't think about, like the radio waves bouncing off of us and the gamma rays that shoot right through us. Given the ubiquity, diversity, and power of light, everyone from neurologists to dermatologists to wellness gurus are trying to harness light waves to enhance and heal the body. And although it sounds pretty fringe, it turns out there's more to light than meets the eye.

In part because of the clear impact UV light has on the skin, dermatology has led the charge in using light therapeutically — harnessing red, blue, and even UV light itself to get rid of acne, eczema, and pre-cancerous skin cells. More recently, anesthesiologists started to explore whether green light can be used to dull the pain from migraines and fibromyalgia. More than any other wavelength, though, infrared light appears to have the most therapeutic potential, and advocates claim it can treat everything from arthritis to Alzheimer's disease.

While it may seem far-fetched that light has all these effects on the body, it begins to make more sense when you think of light as a form of energy. That energy can affect the behaviour of the electrons in atoms that are in, well, everything. What we experience as visible light is really just one small portion of what's called the electromagnetic spectrum, which consists of different wavelengths of energy-carrying photons. This spectrum ranges from radio waves, which are very long, low-energy wavelengths, to gamma rays, the shortest and highest-energy wavelengths. It includes microwaves and X-rays, too.

What is infrared therapy?

Infrared light is one of several innovative therapies that are being trialled for the management of patients with acute or chronic pain. The therapy uses certain wavelengths of light that are delivered to sites of the body that have injuries.

Unlike ultraviolet light - which has damaging effects upon the tissues and cells of the body - infrared light helps cells regenerate or repair themselves. Infrared light also improves the circulation of oxygen-rich blood in the body, promoting faster healing of deep tissues and relieving pain.

Pain relief

Infrared saunas may be helpful in at least relieving serious pain for patients with conditions such as rheumatoid arthritis. In one study, 17 rheumatoid arthritis patients and 17 ankylosing spondylitis patients were treated over a four-week period with eight infrared sauna sessions. Improvements of pain and stiffness were "statistically significant," with comfort felt especially after sessions and no enhancements in disease activity.

While chronic pain relief and FIR technology have been studied, the evidence of its positive effects is limited. Of 46 patients with chronic pain, people in the sauna test group were more likely to have improved sleep and/or have returned to work after two years of therapy, in addition to improvement in pain behaviour and anger scores.

When it comes to pain relief from strength or endurance training, a small study involving ten healthy and physically active men found that the deep penetration of infrared heat may help athletes recover from tough workouts faster.

One of the characteristics of infrared light is its ability to penetrate below the skin layers, providing a much greater depth which is able to effectively provide pain relief. In fact, this invasive, natural, and painless method can provide a vast range of health benefits, without damaging the skin through UV radiation.

Infrared light is the heat people feel when exposed to the sun. The skin naturally radiates infrared heat every day. Infrared light has shown immense health benefits, from pain relief to reducing inflammation.

Invisible

The word "infrared" means "below the red," so infrared light has frequencies lower than the red light you can see. This is similar to low sound vibrations you feel rather than hear. Since you cannot see infrared light, most of an incandescent bulb's light is wasted, as is a candle's. You might grab a pan on the stove, not realizing it's hot until you burn yourself. Although life might be easier if you could see IR, your eyes are not equipped for it.

Line of Sight

Being a form of light, infrared moves in straight lines. If you've ever used a remote control in a room with furniture, pets and people, you know if anything gets between you and your television, the remote won't work. Scientists call this line-of-sight transmission, meaning you need to see the target to send infrared light to it. If it's around a corner, behind a big dog or beyond the horizon, you are out of luck.

Heating

From grade-school science class, you may recall that you can send heat by conduction, convection and radiation. Of these three, radiation is the fastest, moving at the speed of light. In addition to sheer speed, Infrared radiation simplifies heating by removing the need for direct contact between a hot object and the one you want to heat. You can control radiant heat easily by turning the power up or down.

Production

The ease of making and controlling IR is one of its key advantages. You can make IR with fire or a light bulb. Your body produces IR as you sit and read this. The global communications network that powers the Internet depends largely on infrared light made by inexpensive electronic devices.

How safe is infrared therapy?

Cardiovascular Health

One of the key health benefits of infrared therapy is an improvement in cardiovascular health. Infrared light increases the production of nitric oxide, a vital signalling molecule that is important for the health of blood vessels. This molecule helps relax the arteries and prevents blood from clotting and clumping in the vessels. Aside from these, it also combats free radicals to prevent oxidative stress and regulate blood pressure.

Nitric oxide is essential in improving blood circulation, which provides more oxygen and nutrients to injured tissues. Thus, infrared light hastens wound healing and stimulates the regeneration of injured tissues, reducing inflammation and pain.

man and woman running on treadmill

Pain and Inflammation

Infrared therapy is an effective and safe remedy for pain and inflammation. It can penetrate deep through the layers of the skin, to the muscles and bones. Since infrared therapy enhances and improves circulation in the skin and other parts of the body, it can bring oxygen and nutrients to injured tissues, promoting healing. It helps ease pain, relieve inflammation, and protect against oxidative stress.

Heart health

According to a review of published evidence regarding infrared saunas and heart health, FIR may normalize blood pressure and treat congestive heart failure, but this evidence is limited and moderate at best. At least three scientific papers support using infrared saunas for people with coronary risk factors, such as hypertension, obesity, and smoking; however, there were problems with some of the reporting methods used by study authors to give the results more validity of the studies were too short of duration.

That said, there is one long study on heart health and saunas, and it's a good one, involving 2,300 middle-aged men in Finland.

Over a period of 20 years, researchers found that the men who went to sauna more frequently died less, particularly from cardiovascular disease and stroke. The Finnish consider their saunas "unique" (and they're not infrared), with nearly as many saunas in Finland as TV sets. Most Finnish people go to the sauna once a week, but only half of men and one-third of women meet exercise recommendations, leading researchers to note that the saunas may have an effect on cardiovascular conditioning as they raise the heart rate, similar to exercise. But, even the authors of this study noted that further research should be done, and we don't see how they could have tracked all other lifestyle and environmental factors that could have led to these results.

In another systemic review of heart health studies, infrared saunas were found to increase peripheral blood circulation possibly, and artery blood flows, along with promoting capillary dilatation. Because saunas may simply decrease oxidative stress, some of the claims may hold true, but we'd like to see more human studies and larger sample sizes before truly weighing in.

Muscular Injuries

Infrared therapy improves the action of the mitochondria within cells, thus triggering the growth and repair of new muscles cells and tissues. In other words, infrared light can hasten the repair process after a muscle injury.

woman sitting on bed holding sore lower back
 

Detoxification

Infrared therapy can be applied through saunas. Detoxifications are important since they may strengthen the immune system. At the same time, detoxification aid biochemical processes to function properly, improving food digestion. In infrared saunas, the body's core temperature increases, leading to detoxification at the cellular level.

Anti-aging

Many infrared sauna owners promote a "natural anti-aging" benefit to their saunas to help get customers in the door. But can we really reverse the effects of aging with a sauna session?

Researchers in one study looked into the effects of infrared radiation on collagen and elastin production in dermal fibroblasts, in addition to how the technology would affect photo-aged facial skin lesions. Twenty patients with mild-to-moderate face wrinkles and hyper-pigmented lesions received daily FIR treatments for six months, after which, collagen and elastin production was found to have increased. Most patients thought their skin texture improved, while about 1 in 4 thought their skin colour tone did as well — though researchers did not see any improvements in hyper-pigmented lesions.19 Although infrared saunas could help reduce wrinkles, some of the results may be in the eye of the beholder.

It should be noted that some types of near-infrared radiation (NIR) have detrimental effects on the skin, with chronic exposure to heat via NIR leading to more wrinkles. However, NIR is also used as a type of light therapy, and it all depends on the level of irradiance.

Potential Cancer Cure

Infrared therapy is a potentially viable cancer treatment. Studies show significant activation of nanoparticles when they are exposed to infrared radiation, rendering them highly toxic to surrounding cancer cells. One such modality is photoimmunotherapy, using a conjugated antibody- photo absorber complex that binds to cancer cells.

Scientists have discovered that infrared light can penetrate cells and tissues in the body by an inch and a half and heat them up. This has spurred the rise of infrared saunas, which have gained popularity in recent years through endorsements by the celebrity Pseudoscience Squad — Gwyneth Paltrow, Jack Dorsey, Joe Rogan, Tom Brady, and the Kardashian sisters. 

Manufacturers and proponents of infrared saunas make the classic Wellness™ claim that they "detoxify" the body — and by "detox," they mean by enabling you to sweat in a special way that purges your cells of heavy metals, calories, and signs of aging. In case it needs saying, sweat is the same no matter how it's produced, and it does not detoxify the body (the liver and kidneys do). The purpose of sweat is to cool you down when it evaporates off your skin.

While traditional saunas heat up the ambient temperature of the room, infrared saunas heat the cells in your body. Infrared lamps used in incubators for premature babies and in cafeteria heat lamps to keep French fries warm employ the same technology. Because they heat you up from the inside out instead of outside in, infrared saunas run cooler than regular saunas, maxing out at 120 degrees Fahrenheit instead of 200 degrees. This means you might be able to last longer in an infrared sauna than you could in a traditional one. Other than that, there's really no difference between the two, and the general consensus seems to be that any health effects conferred by infrared saunas likely stem from the heat rather than the light itself.

This is not to say that saunas — infrared or otherwise — don't have their benefits. There is some evidence, particularly from Scandinavian and East Asian studies, that they may improve circulation and cardiovascular function, reduce pain, and speed up muscle recovery. Regular sauna use is also linked to a longer lifespan, although whether that's due to the sauna itself or a result of prioritizing relaxation and well-being is impossible to say.

"The mid-infrared light in the sauna is really used more for health, wellness, athletic recovery, possibly increased athletic performance," says Michael Hamblin, a principal investigator at the Wellman Center for Photomedicine at Massachusetts General Hospital. "There's some evidence that it helps with all sorts of systemic disorders."

Notice Hamblin said mid-infrared light, which has longer wavelengths and is the kind of light used in infrared saunas. This is in contrast to near-infrared light, which has shorter wavelengths and is used in infrared helmets — literally a helmet or headset with small infrared lights glued to the inside.

Dangers of Infrared Radiation

Infrared radiation can only penetrate approximately 4 cm into the human body, so the primary risks of infrared radiation exposure are to the skin and the eyes.

 

Additionally, large-scale safety trials should determine the long-term side effects of infrared radiation, different wavelengths, and light "dosages."

Therefore, this is not intended to be a complete list of potential adverse effects of infrared radiation.

anti ageing

Skin Damage

Approximately 65% of the infrared radiation that reaches the human body penetrates to the dermis before absorption. At this point, one potential concern is an increase in photoaging (aging due to light).

UV rays are the main agents of photoaging, but one study found that increased exposure to infrared radiation increased MMP-1 production. MMP-1 is a potential contributor to photoaging, which decreases collagen and elastin production in the skin.

The increase in skin temperature can also have negative effects. An increase in temperature via induced heat shock can lead to the creation of reactive oxygen species, which may cause damage over time.

Infrared radiation may also harm tattooed skin. In one man, far infrared light cause skin inflammation (pseudolymphoma)

There are numerous papers showing that near-infrared exposure causes photoaging of the skin, similar to the effect of exposure to ultraviolet light. Photoaging is the formation of coarse wrinkles, uneven skin pigmentation, loss of skin elasticity, and a disturbance of skin barrier functions (Yaar, 2006). 

Starting with Kligman's paper in 1982, it was noted that near-infrared alone caused skin damage and skin aging in albino guinea pigs similar to that from ultraviolet light.

Kim et al. 2005 found near-infrared caused wrinkles in hairless mice. Since then, it has been demonstrated and confirmed that near-infrared (IR-A) causes the production of reactive oxygen species (ROS) in human dermal fibroblasts, which cause skin aging. Fibroblasts are cells in the dermis layer of the skin which produce collagen and the extracellular matrix. Healthy collagen gives skin its structure and youthful appearance. These ROS cause harm on their own, but they also trigger increased gene expression of matrix metalloproteinase-1 (MMP-1) in the skin (Schieke et al., 2002; Kim et al., 2006; Schroeder et al., 2007; Buechner et al., 2008; Cho et al., 2008; Schroeder et al., 2008; Calles et al., 2010; Costa et al., 2015). This is a major factor in skin aging because the MMP-1 enzyme degrades type-1 and type-3 collagen as well as elastic fibres (Krutmann 2011 ßSkin Aging in Nutrition for Healthy Skin (book)first reference in Costa 2015).

Premature aging of the skin is not a desirable side effect in an infrared sauna that one is purchasing to improve and restore health. This is a near-infrared sauna danger that is not a risk in a far infrared sauna.

water being poured into glass

Overheating and Dehydration

The primary risk of either a dry or steam sauna is overdoing it, as explained by physician Andrew Weil. Overheating can lead to fainting and dehydration, and dehydration can cause electrolyte depletion. Elderly people are more prone to overheating, as sweat gland function decreases with age. Circulatory conditions also can be a problem, as noted by Sauna Talk. A child's body temperature also rises more quickly than that of adults, so parents should consult with a pediatrician before allowing a child to spend time in a sauna.

Alcohol increases the risk of overheating. Additionally, Sauna Talk advises people taking antihistamines, barbiturates, beta-blockers or diuretics to be cautious about using an infrared sauna. These drugs can impair the ability to perspire and also may cause dehydration. People with certain health disorders may not be able to handle the heat of an infrared sauna safely. These disorders include adrenal suppression, diabetic neuropathy, multiple sclerosis and Parkinson's disease.

Worsening Eczema

Sweating during a sauna may increase itching in people with eczema (atopic dermatitis), according to a "American Journal of Medicine" study. Another study published in the "European Journal of Pediatrics" in December 1989 evaluated children regularly participating in saunas and found that half of those with atopic dermatitis experienced worse symptoms in the sauna.

Silicone Implants

One potential danger particularly associated with an infrared sauna compared to a wet sauna regards silicone implants of any sort. Silicone absorbs infrared heat, as explained by Sauna Talk. Anyone with a silicone implant should check with a doctor before using an infrared sauna.

eye with red background

Eye Damage

The lens of the eye is extremely sensitive to infrared radiation. Long-term exposure to high power sources may contribute to cataract formation.

Infrared radiation can damage crucial proteins that facilitate the normal function and passage of ions and enzymes through the lens. This could reduce the clarity of the lens.

Near-Infrared Sauna Dangers: Cataracts

Near-infrared has been proven to promote cataract development with high or repeated exposure. Cataracts are an age-related clouding of the lens of the eye and are the leading cause of blindness worldwide. A large study in 1984 showed that long term exposure to near-infrared is associated with increased cataract formation. Iron, steel, and glass workers are exposed to high levels of near-infrared. Thirty-two per cent of ironworkers had early signs of cataract formation by age 60, compared with 12% of controls. By age 70, 16% of glassworkers required cataract surgery, compared with 1% of controls (Lydahl, 1984). 

Animal studies have since confirmed that near-infrared promotes cataract formation, and have uncovered some of the mechanisms. Crystallin is a soluble lens structural protein that maintains the transparency of the lens. Crystallin degradation and decreased production cause a clouding of the lens and are associated with cataract formation. A study in 2011 found that near-infrared exposure decreases crystallin levels, and changes its structure to a less soluble form (Aly, 2011). A study in 2013 showed an increase in matrix metalloproteinases in the cornea and the lens after exposure to near-infrared, an enzyme that degrades structural proteins. This parallels one mechanism by which near-infrared causes skin damage (Dadoukis, 2013). Scientists have found only wavelengths under 3000nm (near and mid-infrared) to cause this damage to the eye. Shorter wavelengths, 780um to 1400nm (near-infrared), are the most damaging. Wavelengths over 3000nm (far infrared) have never been shown to damage the eye.   

The International Commission on Non-Ionizing Radiation Protection (ICNIRP) sets occupational limits on near-infrared exposure. While animal studies have been able to determine thresholds for acute exposure causing immediate cataract formation, there is little data on safe levels of long-term exposure, and thresholds have not been established. The ICNIRP acknowledges that "cataract has been epidemiologically associated with chronic intermittent exposure at low irradiance", as in a near-infrared sauna. 

Caveats

There are not many available human clinical trials that use infrared radiation. Additionally, most of the available human studies are not high quality (not double-blind or have a large sample size).

Consult a doctor before going to an infrared sauna.

Pregnant women, children, the elderly, and people with a weak immune system should avoid infrared light due to a lack of safety data and the dangers of excess heating.

Each day, humans are immersed in infrared radiation from the sun in the form of heat. In fact, infrared saunas are in-demand today, but experts warn of possible health risks. Thermal or heat injuries can happen, depending on the wavelength of the infrared light. Thermal injury can occur even without pain. Also, pregnant women, people with heart diseases, and those who are sick should never undergo infrared therapy.

Moreover, experts warn against using infrared therapy to treat chronic diseases while neglecting the use of medications and recommended treatment procedures. Though infrared therapy promises many health benefits, its study is far from complete. At present, therefore, it should be considered an adjunct to medical treatment, and other regimens should be continued as prescribed.

Near-Infrared Sauna Dangers: Oxidative Stress and ROS

Reactive oxygen species (ROS), such as superoxide (02-), cause damage and need to be detoxified out of the body. This means that they consume some of your body's supply of antioxidants leaving you more vulnerable to harm from other toxins.

Schroeder 2007 specifically found that near-infrared led to the generation of superoxide (02-) originating in the mitochondria of human fibroblasts, leading to MMP-1 expression. It also leads to increased oxidized glutathione (glutathione is antioxidant — oxidized glutathione is the form it has after it is "spent"). Schroeder 2008 also found a reduction in antioxidants in the skin after near-infrared exposure. Costa 2015 found that after near-infrared exposure, there was a significant reduction in catalase and superoxide dismutase, both enzymes that protect against ROS. Darvin et al. 2010, concluded: "Hereby, it has to be considered that IRA irradiation near-infrared) is used only in cases of lesions and injury, i.e., infrequently." Their point is that due to the production of free radicals, habitual near-infrared exposure, as you would have in a near-infrared sauna, is to be avoided.

Near-Infrared Sauna Dangers: Potential to Cause Cancer

Near-infrared (IR-A) has been found to suppress the apoptosis that would normally occur after ultraviolet-B (UVB) exposure (Jantschitsch 2009). Apoptosis is when cells with genetic damage die, to prevent them from becoming malignant. Calles 2010 found that near-infrared exposure affects the expression of 599 genes. Eleven of those genes related to apoptosis. Costa 2015 confirmed that reduced apoptosis is dangerous, especially because they also showed decreased repair of DNA. This is due to a reduction of GADD45a protein (specifically 57.2% decrease at 48 hours, and 34.6% decrease at 72 hours).

Kimeswenger 2016 specifically looked at near-infrared effects on human melanocytes. Melanocytes are cells that produce melanin, which absorbs ultraviolet light to protect the skin. The worst form of skin cancer is melanoma, and it forms in melanocytes. In this study, at 24 hours, by itself, near-infrared did not affect apoptosis, but in combination with UVB, it significantly reduced apoptosis. They then looked at what effect near-infrared was having on DNA repair (since DNA damage is the major trigger for ultraviolet radiation-induced apoptosis). They found that at 6h, 24h and 48h there was no effect from near-infrared on DNA repair. They showed that near-infrared was altering the expression of several apoptosis-related proteins. The conclusion was "Since IRA (near-infrared) does not affect the repair of DNA-damaged melanocytes, the enhanced survival of severely DNA-damaged melanocytes might support the accumulation of UVB-induced mutations, malignant transformation, and ultimately melanomagenesis." This means that evidence shows the possibility that near-infrared is what makes UVB cause melanoma. This is very real and very concerning near-infrared sauna danger.

Infrared therapy is a safe and effective way to reduce pain and treat a wide array of conditions. It seems to be a safe, effective, and drug-free way for long-lasting pain relief. It also helps to heal injured body parts.

With the treatment of injuries come multiple benefits such as pain relief, reduction of inflammation, and the restoration of the function of the affected body part. Other conditions that can be treated by infrared therapy include joint pain, joint inflammation, muscle pain, spine injuries, nerve pain, and sports injuries.

Infrared therapy is a technique by which infrared wavelengths of light are applied to inflamed or diseased tissues. Its proponents believe that by heating the tissues, infrared light improves circulation and decreases inflammation, thereby improving wound healing and other processes.

So far, the best evidence for infrared light is for psoriasis, diabetic ulcers, and general inflammation. Many popular applications of infrared therapy do not have sufficient evidence to recommend it.

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