Scientific Research on the benefits of
regular Sauna Use
The act of bathing in heat for cleansing, healing, and renewal is a time-honored ancient tradition practiced across cultures for thousands of years—from the banyas of Russia to Native American sweat lodges and the iconic Finnish sauna.
Today, modern science is affirming what tradition has long known. Regular sauna use—also called sauna bathing — involves short-term, passive exposure to high temperatures (typically 113°F to 212°F), depending on the sauna type. This thermal stress gently raises the body’s core temperature, triggering a cascade of physiological responses that promote health and resilience. These responses include cardiovascular, neuroendocrine, and cellular protective mechanisms that help restore balance (homeostasis) and prepare the body to better withstand future stressors. Scientific studies have shown sauna bathing may help reduce inflammation, relieve chronic pain, support heart health, and enhance mental well-being.
”Sauna use induces a thermoregulatory response involving neuroendocrine, cardiovascular, and cytoprotective mechanisms that help restore homeostasis and condition the body for future stressors.
Laukkanen et al., 2018; Patrick & Johnson, 2021.Published in Experimental Gerontology
The information provided here is based on emerging scientific research and is intended for general wellness education. It is not a substitute for professional medical advice, diagnosis, or treatment.
Sauna use is more than a relaxing ritual—it’s a scientifically supported health practice
At The Source, we honor the traditions of Finnish and infrared saunas while integrating cutting-edge research to promote longevity, vitality, and resilience. Below, you’ll find a curated breakdown of how sauna therapy supports cardiovascular and whole-body health—organized by benefit for clarity and ease of reference.
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Click on the items below to learn more about the benefits of regular sauna use.
CARDIOVASCULAR HEALTH
Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events.
Sauna bathing is more than just relaxing—it may significantly improve cardiovascular health. A growing body of research shows strong links between regular sauna use and reductions in heart-related mortality and risk factors.
Reduced Cardiovascular Mortality
Findings from the Kuopio Ischemic Heart Disease (KIHD) study show:
- Using a sauna 2–3 times per week was associated with a 27% lower risk of cardiovascular disease (CVD) mortality.
- 4–7 times per week was linked to a 50% lower risk of CVD mortality.
- The risk of sudden cardiac death was 63% lower in frequent sauna users compared to once-weekly users.
- Longer sauna sessions (≥19 minutes) offered more robust benefits compared to shorter sessions (≤11 minutes).
(Laukkanen et al., 2015)
Sauna = Passive Cardio
Sauna bathing elicits cardiovascular responses similar to moderate- to vigorous-intensity exercise:
- Heart rate can rise to 100–150 bpm, similar to aerobic exercise.
- A 25-minute sauna session produced cardiac loads nearly equivalent to moderate-intensity physical exercise.
(Ketelhut & Ketelhut, 2019)
These effects include:
- Decreased systolic and diastolic blood pressure
- Improved arterial compliance and flow-mediated dilation (a marker of endothelial function)
- Increased left ventricular ejection fraction
(Imamura et al., 2001; Lee et al., 2018; Gayda et al., 2012)
Sauna + Exercise = Synergistic Benefits
Cardiorespiratory fitness and frequent sauna use together resulted in the strongest reductions in cardiovascular and all-cause mortality.
Those with both high fitness and high sauna use had the lowest risk, showing a synergistic protective effect.
(Kunutsor et al., 2018)
Why It Matters
Cardiovascular disease is the leading cause of death globally, responsible for 17.9 million deaths in 2016. Most cases are preventable through healthy lifestyle behaviors—including sauna use, regular exercise, and stress reduction.
(Roth et al., 2017; Yusuf et al., 2004)
Summary: Sauna use mimics the effects of moderate exercise and protects heart function. – 27–50% lower risk of cardiovascular disease (CVD) mortality with 2–7 sauna sessions per week. (Laukkanen et al., 2015b) – Heart rate during sauna: 100–150 bpm, comparable to moderate-intensity exercise. (Kukkonen-Harjula et al., 1989; Taggart et al., 1972) – Sauna use improves blood pressure, endothelial function, arterial compliance, and ventricular performance.
EXTENDS HEALTHSPAN
Sauna use may contribute to a longer, healthier life. Frequent users had a 40% lower risk of all-cause mortality, independent of other conventional risk factors.
Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events.
Summary:
Frequent sauna use is linked to significantly lower all-cause mortality. –
40% lower risk
of all-cause mortality in frequent sauna users (4–7x/week) vs. once weekly use.
(Laukkanen et al., 2015b)
Reduces Stress & Boosts Mood
Sauna bathing and risk of psychotic disorders: A prospective cohort study.
Heat therapy supports emotional balance. Sauna bathing stimulates endorphin release and reduces stress hormone levels, promoting a sense of calm and clarity.
Congestive Heart Failure
Congestive Heart Failure (CHF) is a progressive condition that impairs the heart’s ability to pump effectively, leading to symptoms such as fatigue, fluid retention, and shortness of breath. While conventional treatment focuses on pharmaceuticals and dietary management, emerging research suggests that infrared sauna therapy may offer a complementary path to relief and improved function.
Waon Therapy Shows Measurable Impact
Study 1: Improved Heart Function & Biomarkers
A multicenter, randomized controlled trial involving 149 patients with advanced CHF found that just 2 weeks of infrared sauna therapy (Waon Therapy) led to:
- Reduced B-type natriuretic peptide (BNP) levels
- Improved exercise endurance
- Reduced cardiothoracic ratio
- Better overall CHF disease status
Compared to those receiving standard medical care alone.
Study 2: Significant Reduction in Arrhythmias
In another randomized trial, 30 CHF patients with frequent premature ventricular contractions (PVCs)underwent 2 weeks of infrared sauna therapy. Results showed:
- PVCs dropped from an average of 3,161/day to 848/day
- The control group (no sauna) showed no improvement
What is Waon Therapy?
Waon Therapy is a type of infrared dry sauna therapy, delivered at a lower temperature (~140°F / 60°C) to safely warm the body. It’s designed for clinical use and has been shown to improve cardiovascular function without overstressing the heart—making it especially promising for those with CHF.
Takeaway
These studies suggest that infrared sauna therapy may improve cardiac performance, reduce arrhythmias, and enhance quality of life in individuals with CHF—offering hope for a non-invasive, supportive therapy that complements traditional treatment.
Summary: Sauna improves quality of life and heart function in CHF patients. – Reduces B-type natriuretic peptide (BNP), edema, and PVCs. (Tei et al., 2016; Kihara et al., 2004) – Enhances endothelial function and left ventricular ejection fraction.
Ischemic heart disease
Ischemic Heart Disease (IHD)—the most common cause of death in Western countries—is marked by reduced blood flow to the heart muscle due to narrowed or blocked coronary arteries. When traditional interventions like stents or bypass surgery aren’t viable, options for improving heart function are limited. But clinical research has shown that infrared sauna therapy may help.
Study: Sauna Therapy Improves Vascular Function
A randomized controlled trial conducted in Japan investigated the impact of Waon Therapy (a form of infrared sauna) in 24 patients with chronic total coronary artery occlusion who had not responded to standard medical procedures and were not candidates for surgical intervention.
- Patients received 15 Waon Therapy sessions over 3 weeks
- The therapy led to significant improvements in vascular endothelial function, measured by flow-mediated dilation (FMD) of the brachial artery
- The control group, which received only standard medical care, showed no improvement
How It Works
Waon Therapy gently warms the body using far-infrared heat at ~140°F (60°C), stimulating vasodilation, reducing vascular stiffness, and enhancing endothelial function—without placing stress on the heart.
Takeaway
This research suggests that infrared sauna therapy may improve vascular health in patients with severe ischemic heart disease, even when conventional medical and surgical options have been exhausted.
Peripheral artery disease (PAD)
Peripheral Artery Disease (PAD) is a circulatory condition caused by atherosclerosis in the arteries of the legs, lower extremities, and abdomen. It restricts blood flow and often leads to pain, numbness, and limited mobility—especially during walking. Conventional treatment options focus on lifestyle changes and medications, but new research suggests infrared sauna therapy may offer meaningful improvement.
Clinical Findings: Enhanced Blood Flow & Endurance
Pilot Study: 50 Sauna Sessions Over 10 Weeks
In a Japanese pilot study of 20 PAD patients, those who received 50 Waon Therapy sessions over 10 weeks experienced:
- Reduced leg pain
- Increased walking distance and endurance
- Improved lower extremity blood flow
(Tei et al., 2007)
RCT Confirms Similar Results
A subsequent randomized controlled trial of 21 PAD patients confirmed these findings, showing similarly significant improvements in mobility, circulation, and symptom relief.
(Shinsato et al., 2010)
Why Sauna Helps
Waon Therapy gently heats the body from the inside out, promoting vasodilation, enhancing microcirculation, and reducing arterial stiffness—all of which help restore blood flow to affected limbs.
Takeaway
These early studies suggest that infrared sauna therapy may offer a safe, non-invasive way to manage symptoms and improve quality of life for those living with Peripheral Artery Disease.
Cholesterol (Dyslipidemia)
Dyslipidemia—abnormal levels of blood lipids such as cholesterol and LDL—is a major risk factor for cardiovascular disease. While diet, exercise, and medication are the primary treatment approaches, recent research suggests that regular sauna use may also help optimize lipid profiles in healthy adults.
Studies Show Improvements in Cholesterol & LDL
Study 1: Women Show Reduced LDL & Total Cholesterol
In a small clinical study, women who participated in seven 30-minute sauna sessions over 2 weeks experienced:
- Reduction in total plasma cholesterol (from 4.47 ± 0.85 to 4.25 ± 0.93 mmol/L)
- Reduction in plasma LDL cholesterol (from 2.83 ± 0.80 to 2.69 ± 0.83 mmol/L)
(Pilch et al., 2014b)
Study 2: Men Show Similar Cholesterol Improvements
In a separate study, men who completed ten 45-minute sauna sessions over 3 weeks experienced:
- Total cholesterol decreased (from 4.50 ± 0.66 to 4.16 ± 0.54 mmol/L)
- LDL cholesterol decreased (from 2.71 ± 0.47 to 2.43 ± 0.35 mmol/L)
(Gryka et al., 2014)
How Sauna May Help
Heat exposure may support lipid metabolism by enhancing circulation, promoting hormonal balance, and reducing systemic inflammation—all of which contribute to healthier cholesterol levels over time.
Takeaway
Though further studies are needed, these early findings suggest that consistent sauna use may modestly improve cholesterol and LDL levels—adding to its growing profile as a powerful lifestyle tool for cardiovascular wellness.
Blood Pressure & Hypertension
Hypertension—defined as blood pressure of 130/80 mm Hg or higher—is a leading predictor of serious cardiovascular events, including stroke, heart attack, and heart failure. It also contributes to long-term damage to organs like the brain and kidneys, largely due to loss of arterial compliance (Whelton et al., 2018).
Regular sauna use has been shown to lower blood pressure, improve arterial flexibility, and significantly reduce the risk of developing hypertension.
Studies Show Reduced Hypertension Risk
Lower Risk with Frequent Sauna Use
A large Finnish cohort study found that men who used a sauna:
- 2–3 times per week had a 24% lower risk of developing hypertension
- 4–7 times per week had a 46% lower risk
Compared to those who used a sauna only once per week
(Zaccardi et al., 2017)
Immediate Effects on Blood Pressure
In another study, just one sauna session was found to:
- Lower systolic and diastolic blood pressure
- Improve arterial compliance (flexibility of blood vessels)
These effects were still present 30 minutes post-session, demonstrating both immediate and lasting vascular benefits.
(Lee et al., 2018)
A Natural Approach to Blood Pressure Control
Sauna bathing may support non-pharmacological blood pressure management by mimicking some cardiovascular effects of moderate exercise—such as increased circulation, vasodilation, and relaxation of the nervous system.
Takeaway
Regular sauna use appears to be a safe, accessible lifestyle intervention that can help prevent and manage hypertension, support arterial health, and reduce long-term cardiovascular risk.
Summary: Sauna use lowers blood pressure and reduces hypertension risk. – 24–46% lower risk of hypertension with regular sauna sessions. (Zaccardi et al., 2017; Lee et al., 2018)
Endothelial function
Endothelial dysfunction is a key contributor to many cardiovascular diseases, including congestive heart failure (CHF). It occurs when the inner lining of blood vessels (the endothelium) produces fewer vasodilators(like nitric oxide) and/or more vasoconstrictors, leading to impaired circulation and vessel rigidity.
This imbalance compromises vascular health and limits the heart’s ability to pump efficiently.
Study: Sauna Therapy Restores Vascular Balance
In a clinical study of patients with congestive heart failure, just 2 weeks of infrared sauna therapy led to measurable improvements in vascular and cardiac function:
- Improved endothelial function, shown by significant increases in flow-mediated dilation (FMD)—a standard marker of blood vessel health
- Reduced concentrations of brain natriuretic peptide (BNP)—a hormone that rises when the heart is under stress
These improvements indicate both vascular recovery and reduced cardiac burden
(Kihara et al., 2002)
Why It Matters
Endothelial health is foundational to circulation, blood pressure regulation, and heart function. Sauna therapy may promote vasodilation, improve oxygen delivery, and support vascular elasticity, making it a promising non-drug therapy for patients with impaired endothelial function.
Takeaway
Infrared sauna therapy may help restore vascular balance and ease cardiac strain in individuals with endothelial dysfunction and congestive heart failure—supporting a broader therapeutic approach to heart health.
Left ventricular function
Left ventricular dysfunction—often triggered by a heart attack (myocardial infarction)—initiates a cascade of structural and hormonal changes in the body. These adaptations strain the cardiovascular system and significantly raise the risk of future events like ischemic stroke (Hays et al., 2006).
One therapeutic strategy showing promise: infrared sauna therapy.
Study: Thermal Vasodilation Supports Heart Function
Clinical studies have demonstrated that both single-session and long-term sauna use (5 days per week for 4 weeks) can improve left ventricular function in men with congestive heart failure.
- Improvements are attributed to reduced afterload, the pressure the heart must pump against, due to thermal vasodilation (expansion of blood vessels in response to heat)
- These benefits help ease the workload on the heart and improve its pumping capacity
(Tei & Tanaka, 1996; Thomas et al., 2016)
How It Works
By gently widening blood vessels, sauna therapy decreases resistance in the circulatory system—allowing the left ventricle to pump more efficiently. Over time, this may help counteract the progression of heart failure and support long-term cardiac function.
Takeaway
Regular sauna use may offer therapeutic value for individuals with late-stage cardiovascular diseaseby improving left ventricular function and easing cardiac stress—supporting both recovery and prevention.
Heart rate variability
Heart Rate Variability (HRV) measures the subtle variation in time between consecutive heartbeats. It’s a powerful, non-invasive marker of autonomic nervous system (ANS) balance and cardiovascular health. A higher HRV reflects greater resilience and adaptability of the heart, while lower HRV is associated with elevated cardiovascular risk and stress (Acharya et al., 2006; Hillebrand et al., 2013).
Why HRV Matters
The sympathetic (“fight or flight”) and parasympathetic (“rest and digest”) branches of the ANS regulate heart rhythm. Greater HRV suggests a healthy, responsive balance between these systems. Regular aerobic exercise is known to improve HRV by enhancing this autonomic flexibility (Hautala et al., 2009).
Sauna Use Mimics Exercise Benefits on HRV
Study: Sauna Reduces Arrhythmias and Increases HRV
In a study involving CHF patients with frequent premature ventricular contractions (PVCs), sauna therapy (15 minutes/day + 30-minute rest, 5 days/week for 2 weeks) led to:
- Increased HRV
- Marked reduction in PVCs per 24 hours
(Kihara et al., 2004)
Study: Sauna Increases Parasympathetic Tone
In a separate study of 93 men with at least one cardiovascular risk factor, a single 30-minute sauna session resulted in:
- Increased parasympathetic activity
- Improved HRV
- Lower resting heart rate post-sauna (68 bpm vs. 77 bpm pre-sauna)
(Laukkanen et al., 2019b)
Takeaway
Regular sauna use may enhance autonomic nervous system balance, increase HRV, and help regulate heart rhythm—offering potential therapeutic value in cardiac arrhythmia management, especially in patients with CHF.
Summary: Sauna improves heart rate variability (HRV), a key metric of stress resilience. – Increased HRV and parasympathetic activity. (Kihara et al., 2004; Laukkanen et al., 2019b)
INFLAMMATION
While inflammation is a critical part of the immune response, chronic, low-grade inflammation is linked to the development of numerous chronic diseases, including cardiovascular disease, cancer, and diabetes. It also tends to increase with age, accelerating biological decline.
Heat, Exercise & Anti-Inflammatory Effects
Exercise provokes a mild inflammatory response—largely due to a rise in core body temperature—that ultimately promotes the release of anti-inflammatory cytokines like IL-1ra and IL-10, helping regulate the immune system and reduce chronic inflammation (Hoekstra et al., 2020; Petersen & Pedersen, 2005).
Importantly, sauna use may mimic these exercise-induced effects, offering an alternative strategy for reducing inflammation in people with physical or cognitive limitations.
Study: Sauna Lowers Inflammation Markers in Large Population
A large Finnish study of over 2,000 men found a dose-dependent relationship between sauna use and lower levels of C-reactive protein (CRP), a key marker of systemic inflammation and cardiovascular risk:
- CRP levels decreased with increasing frequency of sauna use
(Laukkanen & Laukkanen, 2018)
Study: Sauna Increases IL-10 (Anti-Inflammatory Cytokine)
In a separate study of 22 healthy men, participants underwent:
- Two 15-minute sauna sessions at 98.2°C (208.7°F)
- 5-minute cool shower between sessions
Results showed:
- Increased resting levels of IL-10, an anti-inflammatory protein
- This increase occurred more rapidly in trained athletes
- A slight rise in heat shock proteins (HSPs), which assist in cellular repair
(Zychowska et al., 2018)
Takeaway
These findings support the idea that regular sauna bathing helps regulate inflammation, reduce CRP, and boost production of anti-inflammatory cytokines—potentially offering protection against chronic cardiovascular and metabolic diseases.
Neurodegenerative Disease
Sauna bathing is inversely associated with dementia and Alzheimer’s disease in middle-aged Finnish men.
Research Spotlight: Sauna Use & Brain Health
Reduced Risk of Dementia & Alzheimer’s Disease
In a long-term Finnish study, men who used a sauna 4–7 times per week had:
- 66% lower risk of developing dementia
- 65% lower risk of developing Alzheimer’s disease
Compared to men who only used the sauna once weekly.
These results remained significant after controlling for confounding variables.
Laukkanen et al., 2017
Dramatic Reduction in Risk of Psychotic Disorders
In another large-scale study, frequent sauna users (4–7x/week) had a:
- 77% reduced risk of developing psychotic disorders
- This association held even after adjusting for:
- Inflammatory status (CRP levels)
- Physical activity
- Energy intake & socioeconomic status
This suggests sauna bathing may influence neuroendocrine and inflammatory pathways related to mental health.
📖 Laukkanen et al., 2018c
Takeaway
Frequent sauna use may play a powerful role in preserving cognitive function, preventing neurodegenerative decline, and reducing the risk of serious mental illness—likely via improved circulation, reduced inflammation, and enhanced autonomic balance.
Summary: Frequent sauna bathing reduces the risk of cognitive and psychotic disorders. – 66% lower risk of Alzheimer’s and 65% lower risk of dementia. (Laukkanen et al., 2017) – 77% lower risk of developing psychotic disorders. (Laukkanen et al., 2018c) – Sauna stimulates BDNF, supporting memory, learning, and neuroplasticity.
Mental Resilience
Research Spotlight: Sauna Use, Mood, & Brain Function
Heat Stress Increases Brain-Derived Neurotrophic Factor (BDNF)
BDNF is a powerful neurotrophic protein that promotes neurogenesis, supports neuronal plasticity, and helps regulate mood, memory, and cognition (Kojima et al., 2018; Maniam & Morris, 2010).
- Active in the hippocampus, cortex, and basal forebrain—regions critical for learning, memory, and executive function
- Also produced in skeletal muscle, where it supports repair and regeneration (Pedersen, 2013)
Study: Whole-Body Hyperthermia Increases BDNF
A 20-minute immersion in 42 °C (108 °F) water raised:
- Serum BDNF by 66%
- Core body temp to 39.5 °C (103.1 °F)
- Plasma cortisol significantly decreased
BDNF remained elevated for 15 minutes post-immersion
📖 Kojima et al., 2018
Depression, Inflammation & Anti-Inflammatory Cytokines
Elevated pro-inflammatory markers like CRP and IL-6 are strongly associated with depression (Dinan, 2009). Strategies that promote anti-inflammatory cytokines, such as IL-10, are being explored for their potential antidepressant effects (Roque et al., 2009; Worthen et al., 2020).
Study: Sauna Therapy Reduces Depression Symptoms
Study 1: Chronic Sauna Use Improves Mood
In a 4-week RCT of individuals with mild depression, those who received sauna sessions showed:
- Reduced somatic complaints
- Improved appetite
- Lower anxiety scores
Compared to a control group receiving bedrest
Masuda et al., 2005
Study 2: Single Session Improves Depression for 6 Weeks
In a randomized, double-blind trial, 30 participants with depression underwent a single session of whole-body hyperthermia, elevating core body temperature to 38.5 °C (101.3 °F):
- Significant antidepressant effect observed within 1 week
- Mood improvements persisted for up to 6 weeks
Janssen et al., 2016
Study 3: Response Correlates with Core Temperature Drop Post-Treatment
In patients with major depressive disorder, greater reductions in core body temperature during the 5 days following sauna therapy correlated with stronger antidepressant responses
Hanusch et al., 2013
Takeaway
Heat-based therapies—including infrared sauna and whole-body hyperthermia—may reduce depressive symptoms through:
- Elevation of BDNF
- Upregulation of IL-10
- Reduction in cortisol and inflammation
- Modulation of autonomic and endocrine systems
These findings support sauna use as a holistic, non-pharmacological therapy for improving mood, resilience, and brain function—especially in those with elevated inflammatory markers or impaired autonomic balance.
Summary: Sauna use has antidepressant effects and modulates stress hormones. – Enhances IL-10 (anti-inflammatory cytokine), reduces CRP and cortisol. – Improves depression scores in randomized controlled trials. (Masuda et al., 2005; Janssen et al., 2016)
NATURAL PAIN Relief
Research Spotlight: Sauna Use, Endorphins & Opioid Modulation
Beta-Endorphins: Nature’s Painkillers
Beta-endorphins are powerful, naturally occurring opioids produced in the anterior pituitary gland. They help:
- Suppress pain signaling
- Induce euphoria and mood elevation
- Contribute to the “runner’s high” sensation during exercise
(Basso & Suzuki, 2017)
Studies Show Sauna Use Increases Beta-Endorphins
Repeated sauna exposure has been shown to increase circulating beta-endorphins, contributing to:
- Pain relief
- Mood improvement
- Deep relaxation post-session
Jezova et al., 1985
Kukkonen-Harjula & Kauppinen, 1988
Vescovi et al., 1992
Dynorphin: The Body’s Heat Sensor and Opioid Feedback Loop
While dynorphin—another endogenous opioid—is associated with dysphoria, it plays a key role in regulating body temperature and thermal discomfort.
- Heat activates dynorphin-expressing neurons in the parabrachial nucleus
- This helps trigger heat-defense cooling mechanisms (Tan & Knight, 2018)
Interestingly, after dynorphin binds to kappa-opioid receptors, it increases sensitivity of mu-opioid receptors to beta-endorphins in a feedback loop (Narita et al., 2003).
Takeaway
Regular sauna use activates a biological cascade that both relieves pain and enhances the body’s natural reward system. While the initial heat stress may feel intense, it may actually prime the nervous system for greater endorphin sensitivity and resilience over time.
This makes sauna therapy a promising, non-invasive approach for:
- Reducing chronic pain
- Improving mood naturally
- Balancing neurochemical pathways associated with reward, stress, and discomfort
Summary: Sauna stimulates opioid pathways to reduce pain. – Increases beta-endorphins and sensitizes mu-opioid receptors. (Jezova et al., 1985; Narita et al., 2003)
Hormonal Health
Hormone Health, Longevity & Muscle Preservation
Research Spotlight: Sauna Use & Growth Hormone
Why Growth Hormone Matters
Growth hormone (GH) plays a vital role in:
- Tissue repair and regeneration
- Muscle mass and strength
- Cellular metabolism
- Age-related decline in muscle tone, bone density, and energy
As we age, GH secretion declines, contributing to sarcopenic obesity, frailty, and metabolic slowdown(Garcia et al., 2000).
Study: Sauna Dramatically Boosts Growth Hormone
The degree of GH stimulation depends on temperature, exposure time, and frequency:
Moderate Heat Protocol
- Two 20-minute sessions at 80 °C (176 °F)
- 30-minute cooling period between
- Result: 2x increase in GH levels
(Hannuksela & Ellahham, 2001)
High Heat Protocol
- Two 15-minute sessions at 100 °C (212 °F) dry heat
- 30-minute cooling period between
- Result: 5x increase in GH levels
(Kukkonen-Harjula et al., 1989)
Repeated Daily Exposure (7-Day Protocol)
- Two 1-hour sauna sessions per day at 80 °C
- 16x increase in GH levels by day 3
- GH remained elevated for hours post-session
(Leppäluoto et al., 1986)
Exercise + Sauna = Synergistic Effect
A study also found that combining physical exercise with post-exercise sauna exposure dramatically increases GH levels beyond what either stimulus produces alone (Ftaiti et al., 2008).
Takeaway
Regular sauna use significantly boosts growth hormone, a key player in maintaining lean muscle, reducing fat accumulation, and slowing age-related decline. When paired with resistance training or cardio, sauna therapy may amplify metabolic benefits and improve functional longevity.
IMMUNE FUNCTION
Immunological Resilience & Cellular Defense
Research Spotlight: Sauna Use, Aging & the Immune System
Age-Related Decline in Immune Function
Aging is associated with a progressive decline in immune competence, making older adults more susceptible to:
- Infections
- Autoimmune disorders
- Chronic inflammation
- Poor vaccine response
(Osterloh & Breloer, 2008)
Heat Shock Proteins (HSPs): Sauna-Activated Cellular Guardians
HSPs, particularly HSP70 and HSP90, are molecular chaperones that:
- Protect cells from heat and oxidative stress
- Act as endogenous danger signals when cells are stressed or damaged
- Facilitate antigen-presenting cell activity
- Bind to pathogen-associated molecular pattern (PAMP) molecules
- Modulate immune signaling pathways
These actions enable HSPs to regulate both innate and adaptive immune responses, helping the body defend against threats while maintaining internal balance.
Study Highlight
Regular sauna use increases HSP expression, which may:
- Enhance immune surveillance
- Reduce inflammatory damage
- Improve resilience to infection in aging individuals
Osterloh & Breloer, 2008
Takeaway
By stimulating HSP production, sauna therapy offers a non-pharmacological strategy to boost immune function and counteract the natural decline in immune responsiveness seen with aging. This adds a critical dimension to the therapeutic value of heat exposure—supporting healthy aging from the inside out.
Summary: Sauna reduces chronic inflammation and enhances immune defense. – Lowers C-reactive protein (CRP) and boosts IL-10. (Laukkanen & Laukkanen, 2018; Zychowska et al., 2018) – Elevates immune cell counts and increases HSP70, key in adaptive immunity.
Respiratory Health & Immune Defense
Research Spotlight: Sauna Use & Lung Function
Lower Risk of Pneumonia
Findings from the Kuopio Ischaemic Heart Disease (KIHD) study indicate that frequent sauna use is strongly associated with reduced risk of pneumonia:
- 27% lower risk in men using sauna 2–3x per week
- 41% lower risk in men using sauna 4–7x per week
(Kunutsor et al., 2017)
Sauna & Chronic Lung Disease
Sauna therapy improves pulmonary function in individuals with obstructive pulmonary disease and chronic respiratory conditions, likely through mechanisms such as:
- Reduced pulmonary congestion
- Improved lung capacity and airflow:
- Vital capacity
- Tidal volume
- Minute ventilation
- Forced expiratory volume
(Cox et al., 1989; Umehara et al., 2008; Laitinen et al., 1988)
Fewer Colds with Sauna Use
In a 6-month trial:
- Adults who used a sauna 1–2 times weekly had fewer colds than a control group
- Immune benefits became apparent after 3 months of consistent use
(Ernst et al., 1990)
Mechanisms: Oxidative Stress, Heat Shock Proteins & Immunity
Hyperthermia and sauna use exert cellular protective effects via:
Reduced oxidative stress & inflammation
(Sutkowy et al., 2014)
Increased white blood cells
- Single sauna session increased WBC, lymphocytes, neutrophils, and basophils in trained and untrained athletes
(Pilch et al., 2013)
HSP70: Lung Protection & Immune Activation
- Heat shock protein 70 (HSP70) expression increases ~50% for each °C between 98.6–105 °F
- HSP70:
- Stimulates innate immunity
- Activates natural killer cells
- Signals via Toll-like receptors (TLR2/4)
(Singh & Hasday, 2013; Wallin et al., 2002)
Takeaway
Sauna use enhances respiratory function and offers immune-protective benefits, especially when practiced regularly. These effects are mediated by both physiological improvements in lung function and cellular-level defenses, including the activation of HSPs and immune cells.
Summary: Sauna may reduce the incidence of pneumonia and improve lung function. – 41% lower risk of pneumonia. (Kunutsor et al., 2017) – Improves respiratory markers and reduces colds. (Ernst et al., 1990; Laitinen et al., 1988)
PHYSICAL FITNESS & MUSCLE MASS
Physical Fitness, Muscle Preservation & Healthy Aging
Research Spotlight: Sauna Use & Muscular Health
Why Physical Fitness Matters
- Physical fitness is a strong independent predictor of mortality
- Aging leads to declines in:
- VO₂ max (↓ 10% per decade)
- Muscle strength and mass
- Flexibility and endurance
(Hawkins & Wiswell, 2003; Wilder et al., 2006)
Maintaining fitness is linked to:
- Preserved cognitive function
- Reduced frailty
- Improved quality of life
(Park et al., 2012; Jeoung & Lee, 2015)
Heat Stress as a Fitness Modulator
Sauna-induced heat stress mimics some effects of exercise:
- Increases cardiorespiratory fitness
- Helps preserve muscle mass
- Stimulates mitochondrial biogenesis
Two 60-minute sessions of whole-body hyperthermia at 44–50 °C (111–122 °F) increased:
- Akt/mTOR signaling (muscle growth pathway)
- Heat shock proteins (HSPs)
- Nrf2 expression (cellular resilience, mitochondria)
(Ihsan et al., 2020)
Combatting Muscle Atrophy with Sauna Use
Muscle loss occurs during:
- Aging (sarcopenia)
- Injury or immobilization
- Chronic disease
Sauna use supports muscle preservation by:
- Increasing growth hormone
- Reducing oxidative damage
- Promoting HSP activity (Kokura et al., 2007; Hannuksela & Ellahham, 2001)
Human Study (Hafen et al., 2019)
- Daily local heat to immobilized muscle for 10 days:
- ↓ Atrophy by 37%
- ↑ Mitochondrial function
- ↑ HSP levels
Animal Studies
- 30–60 min at 41 °C (105.8 °F) → ↓ muscle atrophy by up to 32%
- Induced HSP32, HSP25, HSP72 → ↑ muscle regrowth by 30%
(Naito et al., 2000; Selsby et al., 2007)
Heat Shock Proteins: Muscle Guardians
HSPs:
- Reduce reactive oxygen species (ROS)
- Maintain glutathione (cellular antioxidant)
- Repair damaged/misfolded proteins
- Boost basal muscle defense response
(Selsby et al., 2007; Kuennen et al., 2011)
Heat-Induced Muscle Growth Pathways
- Myogenesis activation: 30 min at 42 °C (106 °F) boosted transcription factors tied to muscle growth
- Potential application in managing sarcopenia in older adults
(Obi et al., 2019)
Takeaway
Sauna use, particularly at higher temperatures or with regular frequency, may serve as a powerful adjunct to exercise, or even a standalone modality for those with limited mobility. It activates muscle-preserving biological pathways, boosts mitochondrial health, and reduces muscle breakdown — offering vital support for longevity, strength, and recovery.
Summary: Sauna complements training and supports muscle retention. – Improves VO2 max, increases erythrocytes, and expands plasma volume. (Scoon et al., 2007; Kirby et al., 2020) – Prevents muscle atrophy and stimulates heat shock proteins (HSPs).
Sauna stimulates myogenesis and reduces age-related muscle decline. – Increases Akt/mTORsignaling, mitochondrial biogenesis, and HSP expression. (Ihsan et al., 2020; Obi et al., 2019)
ATHLETIC ENDURANCE
Athletic Performance & Endurance Training
Research Spotlight: Sauna Use & Athletic Endurance
Post-Workout Sauna Use Boosts Endurance
A small intervention study of 6 male distance runners found that sitting in the sauna for 30 minutes, twice a week for 3 weeks post-workout:
- Increased time to exhaustion by 32%
- Raised plasma volume by 7.1%
- Increased erythrocytes by 3.5%
Enhanced oxygen transport and improved endurance
(Scoon et al., 2007)
Heat Acclimation Improves Thermoregulation
Regular sauna use mimics heat training:
- Reduces core temperature strain during future workouts
- Increases sweat efficiency
- Enhances cardiovascular control
Small Study: 9 female athletes using a sauna suit (122 °F for 20 min/day, 5 days) showed:
- Improved thermoregulation
- Lowered perceived effort
(Mee et al., 2018)
VO₂ Max & Performance Gains
Randomized trial (Van de Velde et al., 2017):
- Athletes training in sauna suits improved:
- VO₂ max
- Thermoregulatory response
- Performance time
Sweat rate increased during post-intervention 5 km time trial, indicating improved heat tolerance and endurance capacity.
Athlete Sauna Supplementation Protocol
20 university athletes (Kirby et al., 2020) did:
- 30-minute sauna sessions at 101–108 °C (214–226 °F)
- 3x per week, for 3 weeks, immediately post light training
Results:
- ↓ Heart rate by 11 bpm
- ↓ Skin temp by 0.8 °C (1.4 °F)
- ↓ Rectal temp by 0.2 °C (0.36 °F)
- ↑ VO₂ max
- ↑ Running speed
Continued improvements seen with 4 extra weeks of sauna exposure.
Plasma Volume, Cardiovascular Strain & Adaptation
Heat acclimation:
- ↓ Heart rate at same workload
- ↑ Stroke volume
- ↑ Peripheral blood flow
- Earlier, more efficient sweating response
(Costa et al., 2014; Kukkonen-Harjula et al., 1989)
These responses benefit both trained and untrained individuals
(Costa et al., 2014; Garrett et al., 2012)
Blood Flow Enhancement During Exercise
Heat increases circulation during physical activity.
Study (Smolander & Louhevaara, 1992):
- Handgrip exercise in 149–167 °F sauna
- 2x increase in blood flow in both:
- Exercising limb
- Non-exercising limb
Suggests sauna use may accelerate muscle recovery and nutrient delivery post-training.
Takeaway
Integrating sauna use into an athletic regimen — especially post-exercise — supports:
- Endurance gains
- VO₂ max improvements
- Faster heat adaptation
- Improved blood flow & recovery
Sauna is not only a tool for wellness, but a powerful bio-performance enhancer.
Disclaimer: The information presented is for educational purposes only and is not intended as a substitute for professional medical advice. Always consult your healthcare provider before beginning any sauna therapy regimen.
Need more detail? Reach out to us directly or speak to your provider to learn how sauna therapy at The Source can support your unique wellness journey.
Scientific Research on the benefits of
Cold Water Immersion
The use of cold water immersion (CWI) to promote health and well-being dates back thousands of years. Ancient civilizations around the world embraced cold baths, plunge pools, and natural cold water swims for their restorative effects. As early as 3500 BC, the Edwin Smith Papyrus referenced the therapeutic use of cold water. In 400 BC, Hippocrates documented cold water for its analgesic and medicinal benefits, as well as for relieving fatigue. Even Thomas Jefferson reportedly began each morning with a cold foot bath for six decades.
Today, these time-honored traditions are supported by emerging scientific research. Cold water therapy has been shown to reduce inflammation, improve stress resilience, and enhance metabolic and cardiovascular function—benefits that may promote healthy aging. A 2025 study highlights its potential as a powerful lifestyle intervention to support longevity and vitality (Kunutsor et al., 2025).
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Click on the items below to learn more about the benefits of cold water immersion.
Increased Energy
Cold water immersion significantly boosts norepinephrine, a neurotransmitter involved in alertness, focus, and mood. Noradrenaline levels increase by 530%, which enhances arousal and cognitive function. This increase stimulates the sympathetic nervous system, often referred to as the “fight-or-flight” response. When triggered, it results in a surge of energy as the body manages the physical stress of cold temperatures.
Click to link: longevity.stanford.edu/lifestyle/2024/05/22/jumping-into-the-ice-bath-trend-mental-health-benefits-of-cold-water-immersion/#:~:text=CWI%20also%20activates%20the%20sympathetic,also%20boosts%20energy%20and%20focus.
Uplifted Mood / Reduces Stress and Anxiety
Increases Dopamine , A 250% increase in dopamine, which can affect mood and gives you the feeling of pleasure and satisfaction.
The initial shock of cold water can activate the sympathetic nervous system, which can help the body regulate stress
. Clink to link: https://ufhealthjax.org/stories/2024/the-benefits-of-cold-water-immersion-therapy
IMPROVED ATHLETIC RECOVERY AND PERFORMANCE
Cold water immersion (CWI) is very popular as a method reducing post-exercise muscle stiffness, eliminating fatigue, decreasing exercise-induced muscle damage (EIMD), and recovering sports performance. However, there are conflicting opinions as to whether CWI functions positively or negatively. The mechanisms of CWI are still not clear. In this systematic review, we used meta-analysis aims to examine the effect of CWI on fatigue recovery after high-intensity exercise and exercise performance. A total of 20 studies were retrieved and included from PubMed, PEDro and Elsevier databases in this review. Publication years of articles ranged from 2002 to 2022. In selected studies including randomized controlled trials (RCTs) and Crossover design (COD). Analyses of subjective indicators such as delayed-onset muscle soreness (DOMS) and ratings of perceived exertion (RPE), and objective indicators such as countermovement jump (CMJ) and blood plasma markers including creatine kinase(CK), lactate/lactate dehydrogenase(LDH), C-reactive protein(CRP), and IL-6 were performed. Pooled data showed as follows: CWI resulted in a significant decline in subjective characteristics (delayed-onset muscle soreness and perceived exertion at 0 h); CWI reduced countermovement jump(CMJ) significantly at 0 h, creatine kinase(CK) was lowered at 24 h, and lactate at 24 and 48 h. There was no evidence that CWI affects C-reactive protein(CRP) and IL-6 during a 48-h recovery period. Subgroup analysis revealed that different CWI sites and water temperatures have no effect on post-exercise fatigue recovery. Recommended athletes immersed in cold water immediately after exercise, which can effectively reduce muscle soreness and accelerate fatigue recovery. (Xiao F, Kabachkova AV, Jiao L, Zhao H, Kapilevich LV. Effects of cold water immersion after exercise on fatigue recovery and exercise performance–meta analysis. Front Physiol. 2023 Jan 20;14:1006512. doi: 10.3389/fphys.2023.1006512. PMID: 36744038; PMCID: PMC9896520.)
Click to link: https://pmc.ncbi.nlm.nih.gov/articles/PMC9896520/#s1
IMPROVED CIRCULATION
Cold water immersion initiates a physiological response that enhances circulation. Upon exposure to cold temperatures, blood vessels constrict, redirecting blood flow toward vital organs to preserve core body temperature. Once the body begins to rewarm, this is followed by reactive vasodilation, increasing blood flow throughout the body. This alternating constriction and expansion supports overall cardiovascular function and improves circulation (Tipton et al., 2017).
BOOST THE IMMUNE SYSTEM TO PROTECT AGAINST AGE RELATED DISEASE
Exposure to cold water can activate the lymphatic system, which helps to eliminate waste and toxins from the body. When in contact with cold water, lymphatic vessels constrict, causing the lymphatic system to pump. This process activates the immune system, increasing the white blood cell count and enhancing immune response.
Click to link: https://pmc.ncbi.nlm.nih.gov/articles/PMC4049052/#ref80
BUILDS RESILIENCE AND GRIT
According to Dr. Andrew Huberman, “By forcing yourself to embrace the stress of cold exposure as a meaningful self-directed challenge (i.e., stressor), you exert what is called ‘top-down control’ over deeper brain centers that regulate reflexive states. This top-down control process involves your prefrontal cortex – an area of your brain involved in planning and suppressing impulsivity. That ‘top-down’ control is the basis of what people refer to when they talk about “resilience and grit.” Importantly, it is a skill that carries over to situations outside of the deliberate cold environment, allowing you to cope better and maintain a calm, clear mind when confronted with real-world stressors. In other words, deliberate cold exposure is great training for the mind.”
Click to link: https://www.hubermanlab.com/newsletter/the-science-and-use-of-cold-exposure-for-health-and-performance
IMPROVES METABOLISM
Cold water immersion alters gut microbiome composition to improve energy metabolism and support thermogenesis responses over time. Also improves glucose and insulin sensitivity.
click to link: https://www.foundmyfitness.com/topics/cold-exposure-therapy
Immune System Activation
Exposure to cold water can activate the lymphatic system, which plays a key role in eliminating waste and toxins from the body. When the body encounters cold water, lymphatic vessels constrict, prompting the lymphatic system to pump more efficiently. This increased activity stimulates the immune system, boosting white blood cell production and enhancing immune response.
Better Sleep
Cold water immersion can help lower core body temperature, which can signal the body that it’s time to rest and improve sleep quality.
Click to link:
https://info.ancsleep.com/blog/cold-plunges-and-sleep-how-cold-water-therapy-can-enhance-your-rest#:~:text=Timing%20is%20Key:%20Ideally%2C%20a,core%20temperature%20and%20stimulating%20circulation.
According to Dr. Andrew Huberman,
“By forcing yourself to embrace the stress of cold exposure as a meaningful self-directed challenge (i.e., stressor), you exert what is called ‘top-down control’ over deeper brain centers that regulate reflexive states. This top-down control process involves your prefrontal cortex – an area of your brain involved in planning and suppressing impulsivity. That ‘top-down’ control is the basis of what people refer to when they talk about ‘resilience and grit.’ Importantly, it is a skill that carries over to situations outside of the deliberate cold environment, allowing you to cope better and maintain a calm, clear mind when confronted with real-world stressors. In other words, deliberate cold exposure is great training for the mind.”
— Dr. Andrew Huberman, The Science and Use of Cold Exposure for Health and Performance
