Fad or Legitimacy – Is There a Use for Far Infrared Technology Clothing?
Sportswear is often viewed as a marginal profit opportunity for the relentless pursuit of performance, and we often see new technologies designed to aid recovery by manipulating physiology. Often times, technology begins as medical or therapy specific and moves to examples of sports, including compression, which is now considered essential to many sports, including runners.
Far infrared (FIR) emitting treatments have long been used in physical therapy clinics and now the technology has found its way into the sports environment through the use of FIR enabled clothing. But what is FIR, how does it work and are these garments just another marketing fad?
Should you use infrared for runners?
Well, FIR is a specific wavelength band in the infrared spectrum of electromagnetic ratiation, which our skin thermoreceptors perceive as heat that penetrates up to 4 cm deep. Theoretically, it has been suggested that this stimulates molecules and cells and changes biological function, although the real-world evidence isn't quite as clear-cut, but there is evidence that studies anti-inflammatory, antioxidant, and antimicrobial effects.
A new systematic review published in PLoS ONE has summarized the scientific evidence on the use of far-infrared emitting clothing for sport to determine whether the technology can be used clinically.
Methods
This systematic review used the PRISMA guidelines throughout and was registered with PROSPERO, both characteristics of a methodologically sound systematic review. The review took place in November 2020 and included five databases.
The databases were PubMed, Cochrane, ScienceDirect, Scopus and SPORTDiscus, the following combination of keywords with network terms being used where appropriate:
(((“Bioceramics” OR “Ceramic” OR “Far Infrared” OR “FIR”) AND (Garment OR Clothing OR Apparel OR “Cloth” OR “Glove” OR “Sock”) AND (Exercise OR Performance OR recovery OR physical activity OR physical exertion OR fatigue OR "muscle contraction" OR "muscle damage"))))
Articles were included when published in English or French, due more to the researchers' language skills than France, which was doing a plethora of research on infrared emitting clothing.
Studies were included in the review if they included studies with intra-red clothing as an intervention, in which participants over the age of 18 participated, used outcome measures related to exercise performance or recovery, and included all experimental designs were.
If studies examined other infrared emission therapy such as saunas or electrically operated devices, they were excluded because they had a higher power density and thus a higher radiation intensity. If the textile was not intended for sports or exercise, they were also excluded.
The quality of the studies included in the review was assessed using the 10-point PEDro. When using this tool, a rating of 5 or 6 usually indicates adequate study. The use of PEDro has been questioned in recent years due to concerns that the quality of experiments is being overestimated, which is why the Cochrane Risk of Bias Tool is the recommended tool.
Should You Use Infrared Clothing Clinically?
A total of eleven studies were included in the review, which were divided into two categories. One group of studies looked at the effects of infrared garments worn during exercise and the other after exercise. As you can imagine, the participants were younger people (18-57) who exercised regularly with small samples (14-22).
Nine studies focused on short exercises of the HIIT type, while two studies focused on consecutive and aerobic exercises. Ten studies used clothing for the lower limbs and seven for the upper limbs, and six studies in which both the upper and lower limbs were covered with clothing. These garments included t-shirts, long sleeved shirts, shorts, pants, shin guards, and stockings with a variety of tightnesses.
With regard to the quality of the studies included in the review, a mixed bag was created with four studies with less than 6 and the rest with more than six points. Understandably, the area where points were dropped was obfuscation and randomization, both of which are difficult in smaller studies where an infrared emitting garment is buckled up!
FIR-emitting clothing during training
Exposure to FIR during exercise was no longer than 90 minutes and the results can best be summarized as the inconclusive tendency to ineffectiveness. When cycling with upper and lower limbs covered with FIR clothing or upper limbs, the performance in Vo2 only decreased by 1% when cycling with low or moderate intensity. One study showed an increase in the VO2 peak at the anaerobic threshold in sedentary people, but this can be explained by numerous other factors.
The same applies to runners who showed no change in heart rate, perceived exertion, DOMs or maximum blood lactate. There was also no change in running speed or endurance. What about the impact on recovery?
FIR-emitting clothing after training
The exposure to FIR in the studies after training varied between 2 hours and 5 days. In the three studies that assessed the effects of wearing the clothes overnight, the results were mixed. There was no objective change in recovery in the assessment of strength the next day or in objective tests such as creatine kinase activity. But there was a noticeable improvement in DOMs compared to placebo.
For two consecutive weeks of elite futsal players, there were small positive effects on squat jump performance, 10 meter sprint in week 1 versus placebo. However, these may be due to natural variations in training effects as the improvements were minimal. As with those who wore the Garmets overnight, the reduction in DOMS was strongly linked to the wearing of the garments.
The increases in performance observed in futsal players were not taken into account in three other studies in which the Garmets were used between 30 minutes and 3 days immediately after training.
Brief summary of the FIR-capable garments
Far infrared (FIR) emitting garments had no influence on physical performance if they were worn during exercise
FIR emitting clothing possibly reduces the severity and duration of DOMs
When wearing it after exercise, there is conflicting evidence to suggest that physical recovery is beneficial
The quality of the studies varies, with there being no consensus as to what kind of sport or activity FIR Garmets would be useful for
The physiological advantages of FIR are theoretical and not fully understood
In summary, it is too early to say what type of exercise FIR garmets would be used for, but there is weak evidence that this could be useful in reducing the impact of DOMs if used longer than 3 consecutive days after exercise – which is not realistic for many people, including professional athletes.
