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Sauna

Sauna featured article

Bathing oneself in heat for the purposes of purification, cleansing, and healing is an ancient practice, dating back thousands of years and observed across many cultures. Variations of its use are seen today in the banyas of Russia, the sweat lodges of the American Indians, and, most famously, the saunas of Finland.

Sauna use, sometimes referred to as "sauna bathing," is characterized by short-term passive exposure to extreme heat. This exposure elicits mild hyperthermia – an increase in the body's core temperature – that induces a thermoregulatory response involving neuroendocrine, cardiovascular, and cytoprotective mechanisms that work together to restore homeostasis and condition the body for future heat stressors.

In recent decades, sauna bathing has emerged as a means to increase lifespan and improve overall health, based on compelling data from observational, interventional, and mechanistic studies. Of particular interest are the findings from studies of...

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Episodes

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The Biggest Benefit of Saunas No One Is Talking About

Posted on April 1st 2025 (about 2 months)

In this clip, Dr. Rhonda Patrick and Brady Holmer discuss how sauna use enhances fitness, supports muscle health, and boosts longevity.

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The Best Sleep Hack Few People Know About - Rhonda Patrick

Posted on February 7th 2025 (3 months)

In this clip, Dr. Rhonda Patrick discusses sauna benefits for growth hormone, prolactin, sleep, and her pre-bed heat stress routine.

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Q&A #65 with Dr. Rhonda Patrick (12/7/24)

Posted on December 10th 2024 (5 months)

Dr. Rhonda Patrick discusses _Akkermansia muciniphila_, vitamin B1's effect on blood sugar, emulsifiers in food, and electrolyte supplements.

Topic Pages

  • Sauna

    Sauna use exposes the body to extreme heat and, in turn, induces protective responses that improve health and may increase healthspan.

  • Whole-body hyperthermia

    Hyperthermia stresses the body, activating its repair mechanisms. Whole-body hyperthermia is a therapeutic strategy used to treat various medical conditions.

News & Publications

  • Regular infrared sauna use increases blood vessel density in aged muscles by 33%, though muscle size, strength, and protein synthesis remain unchanged. pubmed.ncbi.nlm.nih.gov
    Aging Heat Stress Muscle Sauna Protein

    Scientists have speculated that regular heat exposure, such as that experienced in a sauna, might help aging muscles adapt in ways that preserve strength and mass. A recent study found that older adults who engaged in infrared sauna sessions regularly experienced a 33% increase in the number of small blood vessels surrounding their muscle fibers.

    Researchers asked 14 healthy older adults (65 to 85 years old) to sit in an infrared sauna (60°C, 140°F) for 45 minutes, three times weekly, for eight weeks. They collected muscle biopsies before and after the heat exposure to measure capillarization—the number of capillaries around each muscle fiber—as well as muscle size. They also tracked muscle protein synthesis using amino acid infusions and ultrasound imaging to assess how well blood flowed through muscle tissue after eating. Finally, they measured leg strength using a one-repetition maximum test.

    After eight weeks of heat therapy, participants had 31% to 33% more capillaries surrounding both type I and type II muscle fibers. However, muscle blood flow, protein synthesis rates, leg strength, and muscle size did not improve. Body weight, body composition, and walking speed also stayed the same. The only physical performance measure that improved was handgrip strength, which increased slightly. Interestingly, systolic blood pressure dropped by 2%, while diastolic pressure and resting heart rate were unchanged.

    These findings suggest that passive heat treatment can increase blood vessel density in older muscle tissue, but this change alone doesn’t improve nutrient delivery, muscle building, or strength. Heat exposure might support muscle health in other ways, but it doesn’t appear to be a replacement for resistance or aerobic exercise. Learn more about the benefits of heat exposure in Aliquot #96: Thermal Stress, Part I: The Science Behind Heat Stress and its Positive Effects on Health.

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  • Post-exercise hot tubs and saunas show minimal, inconsistent benefits in exercise performance enhancement, despite potential physiological effects. bmcsportsscimedrehabil.biomedcentral.com
    Exercise Heat Stress Sauna

    Training in hot conditions can drive marked improvements in endurance by triggering cardiovascular and thermoregulatory adaptations. However, access to heat training chambers is limited, and the physical demands of exercising in high temperatures can be risky or impractical. A recent study found that sitting in a sauna or soaking in hot water after exercise—a practice known as “passive heat acclimation"—might offer some of the same benefits as working out in the heat, but the evidence was weak and inconsistent.

    Researchers reviewed 10 studies involving nearly 200 healthy adults, comparing those who used post-exercise heat exposure via sauna or hot water immersion to those who did not. All participants completed similar exercise training programs, and the researchers analyzed outcomes related to performance in hot or neutral conditions, aerobic capacity, heart rate, body temperature, sweat response, and perceived exertion.

    The analysis revealed little to no improvement in performance for those using passive heat acclimation, identifying only a 4% difference between groups—an effect that was statistically weak and inconsistent across individuals. Heat exposure slightly improved maximum oxygen uptake, sweat rate, and thermal discomfort ratings. However, the overall certainty of the evidence was low to very low, due to small study sizes and inconsistent reporting.

    These findings suggest that while passive heat exposure may exert some physiological effects, its ability to improve exercise performance remains unclear. More rigorous, well-controlled trials are needed before recommending hot tubs or saunas as a reliable substitute for training in the heat. Learn more about heat exposure in this peer-reviewed article by Dr. Rhonda Patrick.

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  • Post-exercise infrared sauna use contributes to a 25% increase in jump height and a 6.8% peak power boost in female athletes—a potential tool for enhancing power production. pmc.ncbi.nlm.nih.gov
    Exercise Performance Muscle Sauna

    Infrared saunas are gaining in popularity among athletes as a recovery tool, but their effects on strength training adaptations remain uncertain. While traditional saunas can impair performance, infrared saunas may offer a more effective and comfortable recovery option. A recent study found that using infrared saunas after exercise enhances power production but doesn’t influence muscle growth.

    Forty female team sport athletes participated in the study, with half using an infrared sauna after training sessions for six weeks. Sauna sessions were done three times weekly for 10 minutes at 50°C (122°F) following their training. All participants underwent body composition measurements and physical performance tests, including sprint tests, jumps, and leg press exercises, before and after the training period.

    Both groups improved in neuromuscular performance and muscle size. However, the infrared sauna group showed greater jump height and peak power improvements, with a 25% increase in jump height and a 6.8% increase in peak power. Five-minute sprint times were also faster in the infrared sauna group, though not statistically significant. While both groups gained lean mass, the infrared sauna group experienced small body mass and fat mass increases. There were no marked differences between the groups in muscle hypertrophy or other body composition changes.

    These findings suggest that post-exercise infrared sauna use enhances power output over time but doesn’t affect muscle growth. Learn more about the benefits of infrared and traditional sauna use in our overview article.

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  • Warming muscles prior to high-intensity exercise boosts power and performance by 11%, suggests a small study on cyclists. link.springer.com
    Exercise Heat Stress Cold Stress Sauna

    Study link:

    Athletes often warm up before a big race, but does heating your muscles make a difference? An early study found that warming muscles boosts performance by 11% during intense exercise—but at a cost.

    Researchers asked four young, healthy adults to perform 20-second high-intensity sprints on an exercise bike under four different muscle temperature conditions: room temperature, after leg immersion in hot water (44°C/111.2°F), and after immersion in cool water (18°C/64.4°F and 12°C/53.6°F). They measured the participants' muscle temperature and analyzed their peak force and power output during each sprint.

    They found that increasing muscle temperature using warm water immersion boosted peak force and power 11% more than resting at room temperature. In contrast, cooling the legs in 18°C (64.4°F) and 12°C (53.6°F) water decreased power output 12% and 21% more, respectively. However, higher muscle temperatures also led to quicker fatigue during the sprints. The beneficial effect of temperature was greater at higher pedaling speeds, with a 10% increase in power for every degree (1°C/1.8°F) increase in temperature at the fastest speed.

    It’s important to note that this was a small study that was conducted several years ago. However, the findings suggest that warming muscles before high-intensity exercise enhances power and performance, particularly at faster speeds. This benefit comes with a trade-off of earlier fatigue, potentially limiting endurance activity performance. Cooling, on the other hand, may reduce power output but could extend endurance by slowing the onset of fatigue.

    Interestingly, research shows that warming the body after exercise—in a sauna, for example—can boost performance. In contrast, cCooling the body after exercise may improve glucose and lipid metabolism, decrease inflammation, improve cognitive performance, and enhance immune function — possibly at the cost of reductions in hypertrophy. Learn more in this episode featuring Dr. Rhonda Patrick.

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  • Whole-body hyperthermia activates muscle hormone irisin and increases neuroprotective factors. www.sciencedirect.com
    Exercise Brain Muscle Sauna BDNF Neurodegeneration

    Exposure to high heat while sauna bathing causes mild hyperthermia – an increase in the body’s core temperature – that induces a thermoregulatory response to restore homeostasis and condition the body for future heat stressors. These adaptations to high temperatures involve increased production of brain derived neurotrophic factor (BDNF), a promoter of neuroplasticity, and irisin, a biomarker of exercise. Findings of a new report demonstrate that whole-body hyperthermia increases BDNF and irisin in healthy young adults.

    Whole-body hyperthermia is a therapeutic strategy used to treat various diseases, including cancer and depression. Previous research has shown that use of a hyperthermia chamber increases BDNF to a greater extent than light intensity exercise. Some research has suggested that BDNF production is stimulated by irisin, a hormone secreted from muscle in response to exercise. Irisin may mediate some of the beneficial effects of exercise and sauna use in humans, but additional research is needed.

    The authors recruited 20 male participants (average age, 22 years) and assessed their baseline heat tolerance using a hyperthermia protocol. Participants reclined in a hyperthermia chamber while the researchers increased the temperature of the chamber by 50 degrees F every ten minutes until the participant reached their personal heat threshold. Next, participants completed ten hyperthermia sessions tailored to their baseline conditioning, during which the hyperthermia chamber was set to a temperature of 150 to 175 degrees F. Following a three-week wash-out period, they completed ten sham treatments over two weeks, during which the hyperthermia chamber was set to a temperature of 75 to 77 degrees F.

    Participants had an average core body temperature of 102 degrees F at the end of each whole-body hyperthermia treatment. Following ten whole-body hyperthermia treatments, participants had a significant increase in circulating irisin levels (6.3 micrograms per milliliter) compared to their baseline levels (5.0 micrograms per milliliter) and compared to their irisin levels following the sham treatment (5.4 micrograms per milliliter). Whole-body hyperthermia treatment also significantly increased BDNF levels (28.3 picograms per liter) compared to baseline (25.9 picograms per liter).

    In healthy young adults, ten whole-body hyperthermia significantly increased irisin and BDNF levels. The authors noted that future studies should explore the effects of whole-body hyperthermia on adipose tissue, which also produces irisin.

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  • Infrared sauna use reduces frailty in older adults. onlinelibrary.wiley.com
    Sauna

    Sauna use is associated with reduced risk for a wide range of age-related conditions, including cardiovascular disease, metabolic dysfunction, and neurodegenerative disease. Evidence from a new study suggests that infrared sauna use reduces frailty in older adults.

    The heat in a sauna is typically provided by conventional electric heaters or infrared heaters. Conventional heaters warm the air to a high temperature, ranging from 70°C to 100°C (158°F to 212°F), and the heat of the warmed air transfers to the body. Infrared heaters emit thermal radiation, which heats the body directly while also warming the surrounding air. They operate at lower temperatures than conventional saunas, typically at 45°C to 60°C (113°F to 140°F).

    Frailty is a progressive biological syndrome defined by the presence of three or more of the following characteristics: unintentional weight loss, fatigue, weakness, slowness, and physical inactivity. Evidence indicates that frailty increases a person’s risk of death.

    The intervention study involved 67 adults between the ages of 66 and 93 years who had been classified as having some degree of frailty. The participants sat in a 60°C infrared sauna for 15 minutes and then rested while lying down and covered with a warm blanket for an additional 30 minutes. The sauna sessions were conducted twice a week for three months.

    The authors of the study assessed the participants' muscle mass, body mass, physical strength, walking speed, cardiorespiratory fitness, cognitive function and mood before and after the intervention. They weighed the participants before and after each sauna session and instructed them to drink sufficient water to compensate for sweat losses.

    They found that 26 percent of the participants showed improvements on measures of frailty. The remainder showed no change (~71 percent) or declined (~2 percent). These findings suggest that infrared sauna use ameliorate measures of frailty in older adults.

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  • Whole-body heat exposure alters skeletal muscle signaling and mitochondrial biogenesis in humans. www.frontiersin.org
    Muscle Sauna

    Muscle loss can occur as part of a disease process, trauma, or aging. Although exercise can prevent muscle loss, some medical conditions or physical limitations can make exercise difficult or even impossible. Findings from a new study indicate that hyperthermia may preserve or increase muscle mass and increase mitochondrial biogenesis.

    Hyperthermia is a state of elevated core body temperature that activates molecular mechanisms that mitigate protein damage and drive the body’s in-house repair systems. Mitochondrial biogenesis is the process by which new mitochondria are made inside cells. Many factors can activate mitochondrial biogenesis including exercise, hyperthermia, and others.

    The study involved nine healthy young men (average age, 35 years) who underwent two 60-minute sessions of passive heat treatment, separated by one week. One session was a whole-body treatment at 44˚C to 50˚C (111˚F to 122˚F) and 50 percent humidity. The other session was a single-leg treatment using a water-perfused suit at approximately 50˚C (122˚F). The authors of the study monitored core, skin and quadriceps muscle temperatures throughout the sessions and took muscle biopsies before, 30 minutes after, and three hours after the heat treatments.

    The whole-body heat treatment switched on the activity of molecules involved in the Akt/mTOR biological pathway, a critical regulator in maintaining skeletal muscle mass. It also increased the expression of heat shock proteins and Nrf2. Nrf2 is a cellular protein that regulates the expression of antioxidant and stress response proteins. Its activity is an indicator of mitochondrial biogenesis. These changes were not evident when the participants received single-leg heat treatment, suggesting that whole-body hyperthermia elicits systemic improvements involved in muscle maintenance and mitochondrial health.

    Interestingly, whole-body heat inhibited the activity of some FOXO proteins and switched on the activity of some genes involved in atrophy. Further study is needed to determine the full effects of whole-body hyperthermia on muscle atrophy.

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