Sauna suit

Traditionally, a sauna suit is commonly worn during physical exercise as an aid to weight loss,[1] for example by boxers, MMA fighters or wrestlers, who wish to qualify for a specific weight class. The body temperature elevation and the profuse sweating induced by wearing the suit cause a rapid loss in body weight by loss of water. Because of this dehydration effect, sauna suits should be used with great caution. The body temperature elevation and water loss while wearing a sauna suit can lead to the possibility of heat stroke and dehydration.[2] Thus, a sauna suit should not be worn in hot conditions. A sauna suit is not intended for use in a sauna.

A 2017 study[3] at Western State Colorado University found that wearing a sauna suit while exercising increased fat loss, improved cardiovascular health and boosted muscle performance.[4]

The researchers recruited 14 people (12 men, 2 women) to participate in this study, half of whom were in the “treatment” group and half of whom were in the control group. It’s important to highlight the fact that, in addition to being low-risk and free of any cardiovascular, pulmonary or metabolic disease, the participants were highly trained endurance athletes. Each individual had six or more years of endurance training and competition experience, and trained for seven to 12 hours each week.[5]

Prior to the onset of the study, the 14 participants underwent a battery of physiological and performance assessments. The order of the tests was randomized to prevent an “order effect,” the participants were instructed to avoid the consumption of alcohol or caffeine for at least 24 hours before each assessment, and there was a minimum of 48 hours between visits to the lab.[6]

During one visit, they performed a maximal exercise test on a treadmill to measure their maximal oxygen uptake (VO2max). A metabolic analyzer was used to establish each participant’s VO2max.[7]

During another visit, they completed a 5K time trial on a treadmill in a simulated hot environment (approximately 95° F/35° C). Participants were instructed to give maximal effort; the pace was initially set to each participant’s personal best in a 5K race.[8]

Finally, during a third visit to the lab, they again completed a 5K time trial, this time in a temperate environment (approximately 64° F/18° C). The same instructions were given to the participants during this test as during the hot-environment run.[9]

Prior to each of the 5K time trials, each participant was weighed, so that weight lost through sweating could be measured via a second weighing immediately after the run. In addition, heart rate, ratings of perceived exertion, core body temperature and time elapsed were recorded every 400 meters and at 5000 meters (i.e., the end of the 5K run).[10]

After the completion of the baseline testing, the participants were paired according to sex, VO2max and their personal best times on the 5K runs, and then randomized into the treatment and control groups so that the groups were as equal in terms of fitness level as possible.[11]

After 14 days of training with a sauna suit there were significant (p < 0.05) improvements in VO2max (+9.1%) and ventilatory threshold (4.6%). The 5km time trial performances in both hot (52 sec) and temperate conditions (38 sec) were significantly faster (p < 0.05) in the sauna suit treatment group after 2wks of training. Relative to the control group, sweat rate and thermoregulation improved (p < 0.05) during the 5km heat time trial after 14 days of training with a sauna suit.[12]

The primary finding of this study is that short-term training in a sauna suit improves heat acclimation and endurance performance. The researchers state that these findings “support the use of a practical and portable sauna suit as a form of heat acclimation to enhance aerobic capacity and endurance performance.”[13]

The athletes who took part in this study saw a 3% increase in their speed after only two weeks of training in the sauna suit. That may not seem like a huge improvement, but it can easily represent the difference between victory and defeat.[14]

Those who exercised with the sauna suit also had lower blood sugar levels, lost more total body weight, burned more fat and increased the amount of calories they burned while in a resting state.[15]

Sauna suits are also worn for body wrapping in some health spas. The wearer is first wrapped in bandages saturated with mineral and/or herbal preparations and then covered with a sauna suit. The objective of this process is to enable the wearer to "sweat out toxins", however there is little scientific evidence to support the effectiveness of this practice.[16] Sauna suits are often worn specifically for such sweat excretion rather for exercise or weight loss.

A medical use for a sauna suit is in the treatment of psoriasis, an inflammation of the skin causing itchiness and discomfort. The symptoms of psoriasis can be relieved by use of ointments and by keeping the skin moist. The wearing of a sauna suit helps to retain skin moisture and to prevent the ointment from leaking out and staining other clothing, furniture or bedding. In medical literature, a sauna suit is also called an "occlusion suit".[17]

• Sportswear (activewear)