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Heat Stress

Episodes

Posted on April 22nd 2025 (about 2 months)

Dr. Andy Galpin & Dr. Rhonda Patrick discuss nutrition, supplement, and recovery strategies for improving exercise performance.

Posted on September 27th 2024 (9 months)

In this clip, Dr. Rhonda Patrick discusses sauna benefits, including exercise effects, mood improvement, immune support, and potential depression treatment.

Posted on April 4th 2024 (about 1 year)

This is my keynote presentation from the 2024 CrossFit Health Summit where I explored how vigorous exercise and heat stress contribute to longevity.

Topic Pages

  • Depression

    Heat stress evokes peripheral-cerebral cytokine release and HPA-axis hyperactivation, impairing monoaminergic signaling and precipitating depressive pathophysiology.

  • Sauna

    Sauna exposure induces heat stress, elevating core temperature and eliciting sympathetic, cardiovascular, and sudomotor thermoregulatory responses.

News & Publications

  • 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.

  • 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.

  • 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.

  • Alzheimer’s disease disproportionally affects women, who account for nearly two-thirds of all cases worldwide. Some evidence suggests female sex hormones influence the pathology and progression of Alzheimer’s disease. A recent study in mice shows that the brains of male and female mice with Alzheimer’s regulate amyloid-beta protein differently, with the hormone estradiol playing a critical role.

    Researchers measured amyloid-beta accumulation in male and female mice when exposed to differing levels of cholinergic tone (acetylcholine release). Then, they examined the effects of removing the ovaries (the primary source of estradiol) and estradiol replacement on this relationship. Finally, using magnetic resonance imaging techniques, they assessed the amyloid-beta burden in the brains of 130 older adults.

    They found that acetylcholine activity and the development of amyloid-related issues in male and ovariectomized female mice were directly linked. This link, however, was not observed in female mice with intact ovaries or females without ovaries that received estradiol. They also found that the age-related decline in acetylcholine worsens the amyloid-beta burden in older adults.

    Amyloid-beta is a toxic protein that clumps together, forming plaques in the brain – a hallmark of Alzheimer’s disease. Cholinergic neurons are vital for cognition and perception. They release acetylcholine, a neurotransmitter that facilitates impulse firing between neurons. Cholinergic neurons are particularly vulnerable to amyloid-beta’s toxic effects, which impair acetylcholine release. The relationship between acetylcholine and amyloid-beta is bidirectional: amyloid-beta aggregation impairs acetylcholine production, in turn increasing amyloid-beta aggregation, creating a vicious cycle.

    These findings suggest that estradiol, a female sex hormone, influences amyloid-beta burden in mice. They also highlight the need for Alzheimer’s research to consider sex differences, the relationship between acetylcholine signaling and amyloid-beta buildup, and the effects of sex hormones to better develop treatment strategies.

    Heat shock proteins inhibit amyloid-beta clumping and reduce amyloid-beta plaque toxicity. Sauna use increases heat shock protein production and activity, potentially reducing the risk of Alzheimer’s disease. Learn more in our sauna overview article.

  • During exposure to temperature extremes or hypoxia (low oxygen levels), cells increase their expression of heat shock proteins to stabilize unfolded proteins and repair damaged ones. This phenomenon, referred to as the heat shock response, occurs at the expense of other cellular proteins to protect the cell. Evidence from a 2016 study suggests that the heat shock response enhances athletic performance in low-oxygen environments characteristic of high altitudes.

    The study involved 21 elite cyclists who engaged in ten 60-minute training sessions in either low-oxygen or hot conditions. Before and after the intervention, they performed a time trial, where researchers tested their tolerance to low-oxygen levels.

    The researchers found that training during heat exposure improved athletic performance nearly as well as low oxygen exposure. Expression of heat shock protein 72 and hypoxia-inducible factor 1-α, a protein that mediates the body’s response to low oxygen levels, increased in both scenarios.

    Heat-shock proteins comprise a large, highly conserved family of proteins that are present in all cells. They play prominent roles in many cellular processes, including immune function, cell signaling, and cell-cycle regulation. Cells maintain a constant level of HSPs to facilitate aspects of the protein synthesis machinery, including assembly, folding, export, turn-over, and regulation. However, stress can upregulate HSP production.

    These findings suggest that training in a hot environment enhances performance in low-oxygen settings. Learn more about heat exposure via sauna use in our comprehensive overview article.

  • The benefits of physical activity on the brain’s aging process are widely known. Evidence suggests that exerkines, a class of molecules released into the bloodstream in response to exercise, drive many of these benefits. Findings from a recent study in mice found that PF4, an exerkine derived from platelets, promotes the production of hippocampal precursor cells in the brains of older mice.

    Researchers injected PF4 into mice and assessed its effects on hippocampal neurogenesis (the growth of new brain cells). Then they investigated the effects of exercise on blood platelets.

    They found that systemic elevation of PF4 levels mitigated age-related declines in brain regeneration and cognitive function, an effect that was dependent upon hippocampal neurogenesis. They also found that exercise triggered platelet activation, which in turn increased the production of hippocampal precursor cells in the brains of older mice.

    These findings underscore the crucial role of platelets in mediating the rejuvenating effects of exercise on the aging brain. It also sheds light on the potential mechanisms that link physical activity with improved brain health in aging, with possible implications for people who are unable to exercise due to advanced age, mobility issues, or various health conditions.

    Interestingly, heat stress also promotes PF4. In a study involving endurance cyclists exercising in hot conditions, PF4 increased by as much as 150 percent. Sauna use has similar effects on PF4. Learn about other effects of heat stress from sauna use in our overview article.

  • Older adults who regularly bathed in hot springs in the evening were less likely to have hypertension, a new study has found. Having hypertension markedly increased the likelihood of having other chronic diseases, however.

    Researchers gathered information about the hot spring bathing habits and overall health of more than 10,000 older adults. The participants lived near Beppu, Japan, an area known for its many hot springs.

    They found that older adults who regularly bathed in hot springs in the evening were approximately 15 percent less likely to have hypertension. Older adults who didn’t frequent the hot springs were roughly 50 percent more likely to have type 2 diabetes, heart arrhythmia, stroke, gout, or abnormal blood lipids.

    Evidence suggests that chronic mental stress promotes hypertension. Research has shown that bathing in hot springs improves mental health and reduces stress. Other research has shown that hot water bathing before bedtime promotes faster sleep onset and better sleep quality, which could reduce the risk of developing hypertension.

    Exercise, hot baths, and sauna use may have similar effects on promoting sleep and reducing blood pressure. Learn more about the effects of sauna use on hypertension in this clip featuring Dr. Jari Laukkanen.

  • Declines in muscle force, power, and contractile function can be observed in older adults, clinical populations, inactive individuals, and injured athletes. Passive heating exposure (e.g., hot baths, sauna, or heated garments) has been used for health purposes, including skeletal muscle treatment. An acute increase in muscle temperature by passive heating can increase the voluntary rate of force development and electrically evoked contraction properties (i.e., time to peak twitch torque, half-relation time, and electromechanical delay). The improvements in the rate of force development and evoked contraction assessments with increased muscle temperature after passive heating reveal peripheral mechanisms’ potential role in enhancing muscle contraction. This review aimed to summarise, discuss, and highlight the potential role of an acute passive heating stimulus on skeletal muscle cells to improve contractile function. These mechanisms include increased calcium kinetics (release/reuptake), calcium sensitivity, and increased intramuscular fluid.

  • Heat shock proteins suppress amyloid-beta toxicity in the brain.

    Amyloid-beta is a toxic peptide that aggregates and forms plaques in the brain with age. These plaques are widely considered a hallmark of Alzheimer’s disease, a progressive neurodegenerative disease that occurs with age and is the most common cause of dementia. Findings from a 2016 study suggest that heat shock proteins suppress amyloid-beta toxicity in the brain.

    Heat-shock proteins comprise a large, highly conserved family of proteins that are present in all cells, across many species. They play prominent roles in many cellular processes and facilitate several aspects of the protein synthesis machinery, including assembly and folding. Increased expression of heat shock proteins prevents protein disorder and aggregation by repairing proteins that have been damaged or misfolded and may offer protection against neurodegenerative diseases and inhibit the aggregation of amyloid-beta, reducing plaque formation.

    The study involved fruit flies, which serve as useful models for studying amyloid-beta anomalies. The investigators engineered a form of heat shock protein 70, called Hsp70, that could pass into the extracellular space and interact with amyloid-beta and studied its effects on the flies' neurological health.

    They found that Hsp70 suppressed the toxicity of amyloid-beta in cells of the flies' eyes, reduced cell death in brain neurons, and helped maintain the neurons' architecture and function. The investigators posited that these neuroprotective effects were directly related to Hsp70’s capacity to bind to amyloid-beta rather than via refolding mechanisms.

    These findings indicate that heat shock protein 70 may suppress amyloid-beta toxicity, thereby reducing amyloid-beta plaque formation in the brain and serving as a potential therapeutic strategy for Alzheimer’s disease. Heat stress, such as that experienced during sauna use, robustly induces expression of heat shock proteins. Learn more about heat shock proteins and sauna use in our overview article.

  • Heat exposure promotes browning of white fat, too.

    The color of fat tissue – white, brown, or beige – determines the role the tissue plays in the body. Whereas white fat is involved primarily in lipid storage, brown fat is involved primarily in heat production. Beige fat, which is co-located with white fat, can adopt either storage or heat-producing properties. Cold exposure, which induces hypothermia, causes white fat to convert to beige fat, a process known as “browning” (or “beiging”). Conversely, findings from a recent study suggest that heat exposure, which induces hyperthermia, also promotes browning of white fat.

    Hyperthermia is an increase in the body’s core temperature that induces a thermoregulatory response involving neuroendocrine, cardiovascular, and cytoprotective mechanisms. These mechanisms work together to restore homeostasis and condition the body for future heat stressors, a phenomenon known as hormesis. Evidence suggests that hyperthermia is beneficial against metabolic diseases, such as type 2 diabetes and obesity.

    The investigators used a photothermal gel that can convert the energy of near-infrared light to heat to induce local hyperthermia. They injected the gel into both sides of the fatty tissues in the groin area of obese mice and applied near-infrared light to one side of the injected area but not the other. The area that received the near-infrared light exposure warmed to 41°C (~5°C higher than normal body temperature for mice), and heat production continued in the exposed area for 12 hours. Then the investigators applied heat to the neck and shoulders of humans, warming the area to 41°C, and found that the tissue continued to produce heat for two hours.

    Next, the investigators gauged the effects of local hyperthermia on metabolism. They found that the mice that received the local hyperthermia treatment were thinner, had better insulin sensitivity, and had fewer fat deposits in their livers than the mice that didn’t receive local hyperthermia.

    These findings suggest that local hyperthermia treatment induces browning and heat production in white fat in both mice and humans and improves metabolic function in mice, providing a potential means for treating obesity. Learn more about the beneficial effects of hyperthermia in our overview article.

  • Depression is a mood disorder characterized by profound sadness, cardiovascular dysfunction, altered sleep patterns, and feelings of guilt or low self-worth. Depression is often accompanied by perturbations in metabolic, hormonal, and immune function. Roughly a third of people who have depression fail to respond to antidepressant drugs. Findings from a clinical trial suggest that hyperthermic baths may reduce some of the symptoms associated with depression.

    Hyperthermia, a state of elevated core body temperature, stresses the body, activating molecular mechanisms that mitigate protein damage and aggregation and activate endogenous antioxidant, repair, and degradation processes. Whole-body hyperthermia is a therapeutic strategy used to treat various medical conditions, including cancer, fibromyalgia, and others. Hyperthermic baths – immersion in very hot water (40°C, 104°F) – offer a means to achieve hyperthermia.

    The randomized two-arm placebo-controlled, eight-week pilot trial involved 36 adults who had moderate depression. Half of the group was randomized to take hyperthermic baths, while the control group received a sham, low-lux green light exposure. Participants received the treatments twice weekly for four weeks.

    The hyperthermic baths involved immersion in 40°C water with the participant’s head out. Participants stayed in the water to the point of discomfort, with a target duration of 30 minutes. These 20 to 30-minute hot water baths typically increased the participants' core body temperature by approximately 1.7°C (3°F). Upon exiting the bath, the participants were wrapped in warm blankets and hot water bottles and kept warm for another 30 minutes.

    At the end of the trial, the participants who received the hyperthermic bath treatment demonstrated clinically significant improvements in measures of depressive symptoms that lasted up to four weeks after the baths were discontinued. They also exhibited improvements in sleep quality. No changes in heart rate variability were noted, however. These findings suggest that hyperthermic baths may be beneficial in treating the symptoms of depression.

  • Aerobic exercise improves cardiorespiratory fitness, a measure of the body’s ability to deliver oxygen to skeletal muscles during sustained physical activity. Findings from a study in Finland indicate that good cardiorespiratory fitness combined with frequent sauna use may work in a synergistic fashion to reduce cardiovascular and all-cause mortality.

    Sauna use exposes the body to extreme temperatures that stress the body, eliciting physiological responses that are remarkably similar to those experienced during moderate- to vigorous-intensity exercise. Prospective studies conducted in Finland revealed that men who used the sauna four to seven times per week were 50 percent less likely to die from cardiovascular-related causes and 40 percent less likely to die from all causes of premature death.

    In a separate analysis, data from the Finish cohort also demonstrated that a high level of cardiorespiratory fitness or frequent sauna use were both independently associated with reduced cardiovascular-related mortality and all-cause mortality. In addition, cardiorespiratory fitness in combination with frequent sauna bathing (three to seven sessions per week) had a synergistic effect on lowering cardiovascular and all-cause mortality. The strongest reductions in mortality were found in people with high cardiorespiratory fitness and high frequent sauna bathing, followed by high cardiorespiratory fitness and low frequent sauna bathing, and then low cardiorespiratory fitness and high frequent sauna bathing.

    Sauna bathing is safe for most adults and can be practiced before or after aerobic exercise to augment the beneficial effects of exercise.

  • A new study found that daily heat treatments applied locally to muscle during 10 days of immobilization prevented the loss of mitochondrial function, increased heat shock protein levels, and attenuated skeletal muscle atrophy by 37% compared to sham control in a small trial in humans.

    I am really glad to see this replicated now in humans. There’s were two similar studies that I covered in past videos, which showed that whole body heat treatment (similar to a sauna) prevented muscle atrophy and increased muscle regrowth after immobilization, however, these were done in mice. The difference is that this shows a pretty similar phenomenon in humans! This isn’t too surprising. The main reason for that is because the mechanism in animal research was already all worked out. The prevention of muscle atrophy and muscle regrowth in mice was shown to be dependent on the robust activation of heat shock proteins. These proteins are highly conserved in humans in function, playing an extremely apparent similar molecular role. More importantly, we already knew from prior research that heat shock proteins increase by ~50% after 30 minutes in a 163 ºF (73 ºC).

    The results of this new study have important implications. While exercise interventions remain the most effective strategy to maintain or increase muscle mass and respiratory capacity, during periods of immobilization due to injury or for other reasons exercise can become more challenging. Heat therapy through modalities such as a sauna or even local heating (as is the case in this study) may ultimately serve as a very useful alternative or adjunct therapy to maintain skeletal muscle metabolic function and preserve muscle mass!

  • New comprehensive analysis of both prospective studies and clinical trials shows frequent sauna use may reduce the risk of heart disease, neurocognitive diseases, mental health disorders, pulmonary diseases, and mortality.

    Temperature, duration, and frequency are in the review. Most of the studies show benefits with a sauna temperature of around 174F for 20 minutes at least 2-3 times per week. Sauna use 4-7 times per week had the most robust effects.

    This review is authored by Dr. Jari Laukkanen. His research has shown that frequent sauna bathing reduces blood pressure, inflammation, oxidative stress, cholesterol, arterial stiffness, and vascular resistance. He has also shown that sauna use contributes to beneficial levels of circulating hormones and other cardiovascular markers.

    You can learn more about the beneficial effects of sauna use on the heart and brain by checking out my podcast with the author of this study, Dr. Jari Laukkanen.

    Sauna episode: https://www.foundmyfitness.com/episodes/jari-laukkanen

  • Four weeks of using the sauna increased resting anti-inflammatory biomarkers (IL-10) and this adaptation happened faster in the already physically active. There was also a small increase in some of the heat shock proteins.

    The sauna protocol used in this study was a little different than other studies I have talked about. This study used two 15 minutes in 208 degrees F separated by a 5-minute cool shower. Previous studies that have shown cardiovascular and brain benefits used a 174 degree F sauna for at least 20 minutes, 4 times a week.

    If you have not already, check out my podcast with Dr. Jari Laukkannen, one of the world’s leading sauna researchers. He gets into the specifics on his research on sauna use for the prevention of cardiovascular disease and Alzheimer’s disease. We also talk about what heat shock proteins are and how they may play a role in Alzheimer’s disease prevention.

    Episode link: https://www.foundmyfitness.com/episodes/jari-laukkanen

  • A new study found that using the sauna was associated with a decrease in a biomarker of inflammation (CRP) in a dose-dependent manner. The more frequent the sauna use…the more robust the effect of lowering inflammation. This study was published early this year from with one of the world’s leading sauna researchers, Dr. Jari Laukkanen.

    He has also shown dose-dependent effects with sauna use on cardiovascular disease, all-cause mortality, and Alzheimer’s disease. Using the sauna 2-3 times per week (20 minutes at 174º F) was associated with: 27% lower cardiovascular disease risk, 24% lower all-cause mortality, and a 20% lower risk of Alzheimer’s disease compared to men that only used the sauna one time per week. Using the sauna 4-7 times per week (20 minutes at 174º F) was associated with: 50% lower cardiovascular disease risk, 40% lower all-cause mortality, and a 66% lower risk of dementia and a 65% lower risk of Alzheimer’s disease compared to men that used the sauna once a week.

  • Phthalates were 35% higher in participants who had eaten out the previous day compared with those who ate at home.

    Phthalates are ubiquitous in plastic products yet I have not phthalates listed on consumer product labels. Unfortunately, I’m not sure if it is required to be listed.

    In 2013, a randomized trial with five families that involved dietary replacement with organic foods that lacked plastic packaging found that phthalates increased 2000% during the trial because the chemical was found in organic imported spices and dairy products.

    Other studies have found that phthalates are excreted through sweat suggesting that forced perspiration such as from exercise and/or using a sauna or other types of heat stress may be a good way to eliminate these potentially harmful compounds.

    Link to 2013 phthalate trial: https://www.nature.com/articles/jes20139

    One excretion study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3504417/

  • Using the sauna 3x per week was associated with a 24% reduction in high blood pressure. This study included close to 2,000 middle-aged men that were followed for 20 years. The results were adjusted for many possible confounding factors including baseline age, alcohol consumption, BMI, physical exercise, socioeconomic status, systolic blood pressure, smoking status, type 2 diabetes, previous heart attack, resting heart rate and serum low-density lipoprotein cholesterol. Anyone that follows me knows that I talk about saunas A LOT. I interviewed the senior author of this study, Jari Laukkanen, M.D., Ph.D. Dr. Laukkanen has been conducting long-term trials looking at the health effects of sauna use in a population of over 2,000 middle-aged men in Finland. The results? Massive reductions in mortality and memory disease in a dose-response fashion at 20-year follow-up. In the podcast, we talk about the details of how long each sauna session was and the average temperature of the saunas. It is a short episode (~25 minutes) that is well worth a listen! Video podcast: https://www.youtube.com/watch?v=jL7vVG_CFWA

  • This study included over 2,000 middle-aged men that were followed for 20 years. The results were adjusted for many possible confounding factors including baseline age, alcohol consumption, BMI, physical exercise, socioeconomic status, systolic blood pressure, smoking status, type 2 diabetes, previous heart attack, resting heart rate and serum low-density lipoprotein cholesterol.

    One of the reasons I find this study so compelling even though it is associative data and does not establish causality is because the sauna activates heat shock proteins, which have been shown in countless animal studies to play a causal role in preventing Alzheimer’s disease and other neurodegenerative diseases.

    Anyone that follows me knows that I talk about saunas ALOT. I have a couple of videos where I discuss the effects of the sauna on longevity and in muscle mass and endurance. I discuss the role of heat shock proteins in both videos. I also have free reports with references covering all these topics that you can download on my website (foundmyfitness.com). Sauna longevity video: https://www.youtube.com/watch?v=eWKBsh7YTXQ Sauna muscle/endurance video: https://www.youtube.com/watch?v=aHOlM-wlNjM&t=1s

  • Is there any research or even supported notion behind the idea that exogenous use of various hormones that are stimulated via heat stress (such as growth hormone) would disrupt the body’s affinity to respond to the hormetic stress?

    I understand that there probably is not much to go off of, but this is more of a question of theorizing exogenous introduction of various compounds on natural pathways that stimulate these.

    If Dr. Rhonda P had to guess, what would she think? I could see it being both synergistic and disruptive.

    Have we looked at the effects of fasted sauna use vs non fasted as well? This is something i do, post workout, typically fasted for 20 hours.

    THANKS

    https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-2007-971895 http://europepmc.org/abstract/med/3218898