What are the benefits of infrared sauna usage?
What is Infrared Sauna?
Sauna use, sometimes referred to as "sauna bathing," is characterised 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 participants in the Kuopio Ischemic Heart Disease Risk Factor (KIHD) Study, an ongoing prospective population-based cohort study of health outcomes in more than 2,300 middle-aged men from eastern Finland, which identified strong links between sauna use and reduced death and disease. At Fast Twitch we offer 30, 45 and 60 minute infrared sauna sessions.
"Men who used the sauna 4-7 times per week had a 66% lower risk of developing dementia compared to men who used the sauna only one time per week." "Men who used the sauna 4-7 times per week were 77% less likely to develop psychotic disorders, regardless of the men's dietary habits, socioeconomic status, physical activity, and inflammatory status."
Humidity
Saunas can be either dry or wet. In a dry sauna, the relative humidity is low (10 to 20 percent). A common practice in Finland, called löyly, is to throw water on the heater rocks to increase the humidity slightly. A wet sauna may feel (subjectively) hotter than a dry sauna and is harder on the cardiovascular system, due to the reduced evaporative cooling.
Duration and temperature
Finnish-style sauna bathing involves one to three sessions of heat exposure lasting five to 20 minutes each, interspersed with periods of cooling. The KIHD studies that found a dose-dependent reduction in cardiovascular-related mortality, all-cause mortality, and Alzheimer's disease incidence typically involved saunas that were heated to a temperature of at least 78.9°C (174°F) for at least 20 minutes. These studies found that the amount of time spent in the sauna also affected cardiovascular-related mortalities, with a longer duration of 19 minutes or more having a more robust effect than 11 to 18 minutes on lowering the mortality rate.
What are the health benefits associated with sauna use?
Cardiovascular health
Heat exposure induces protective responses against the deleterious biological processes that drive cardiovascular disease and related disability. Furthermore, in a study involving 19 healthy adults, the effects of a single 25-minute sauna session were comparable to moderate physical exercise concerning cardiovascular measures.
Like exercise, long-term sauna use generally improves blood pressure, endothelial function, and left ventricular function, and reduces inflammation.
Cardiovascular disease
Cardiovascular disease is largely preventable with lifestyle behaviours such as sauna use. "Compared to men who only used the sauna once per week, moderate sauna users (2-3 times per week) are 22% less likely to experience sudden cardiac death, and frequent users (4-7 times per week) are 63% less likely to experience sudden cardiac death."
Congestive heart failure
Congestive heart failure, or CHF, represents the culmination of all forms of cardiovascular disease. Findings from a prospective, multicentered, randomised controlled trial involving 149 patients with advanced CHF demonstrated that two weeks of waon therapy improved the patients' endurance, heart size, and disease status compared to those who received standard medical care.
Ischemic heart disease
A randomised controlled trial examined the effects of sauna use in 24 patients with ischemic heart disease with chronic total coronary artery occlusion (full blockage of one or more of the arteries that supply the heart) who had not responded to non-surgical procedures and were not candidates for surgical interventions. The findings demonstrated that 15 waon sessions given over three weeks improved the patients' vascular endothelial function. No improvements were observed in the control group that received standard medical care.
Peripheral artery disease
Peripheral artery disease, or PAD, is a painful and debilitating condition in which the arteries that supply the head and extremities narrow. A pilot trial involving 20 patients with PAD who received 50 waon sessions over a period of 10 weeks demonstrated improvements in pain levels, walking endurance, and lower extremity blood flow. A similar randomised controlled trial involving 21 patients with PAD showed comparable improvements.
Dyslipidemia
Dyslipidemia, or abnormal blood lipid levels, is a strong predictor of cardiovascular disease risk. Two small studies have shown that regular sauna use modulates serum cholesterol and lipoproteins in healthy adults.
Hypertension
Hypertension, defined as a systolic pressure of 130 mm Hg or higher, or a diastolic pressure of 80 mm Hg or higher, is a chronic elevation of blood pressure. It is a robust predictor of future incidence of stroke, coronary heart disease, heart attack, heart failure, and cardiovascular-related death
For example, men who used the sauna two to three sessions every week were found to have a 24 percent lower risk of developing hypertension, and men who used the sauna four to seven times per week had a 46 percent lower risk for hypertension, compared to men who used the sauna only once per week
Inflammation
Inflammation is a critical element of the body's immune response that involves immune cells, cell-signalling proteins, and pro-inflammatory factors. C-reactive protein, or CRP, one of several blood proteins often referred to as acute phase reactants, participates in the body's inflammatory cascade. Elevated CRP is associated with the development of atherosclerosis, loss of arterial compliance, and incidence of cardiovascular events. Sauna use, however, reduces blood levels of CRP. In a study of more than 2,000 men living in Finland, CRP levels were inversely related to the frequency of sauna bathing in a dose-response fashion, with lower levels linked to greater frequency.
What are the cognitive & mental health benefits of sauna usage?
Enhanced neurogenesis
Heat stress and exercise increase the expression of brain-derived neurotrophic factor, or BDNF, a protein that acts on neurons in the central and peripheral nervous systems, to promote the growth of new neurons. BDNF modulates neuronal plasticity and ameliorates anxiety and depression from early-life stressful events.
Cognitive decline
The normal cognitive function relies on sufficient blood flow to the brain and peripheral nervous system, so cardiovascular diseases and cognitive decline often go hand-in-hand.
In addition, heat exposure increases the production of BDNF to promote neurogenesis – the growth of new neurons in the brain (as described above). Findings from a large observational study of middle-aged men living in Finland demonstrated that men who used the sauna four to seven times per week had a 65 percent reduced risk of developing Alzheimer's disease, compared to men who used the sauna only one time per week.
Effects of Sauna Usage on Depression
Elevated biomarkers of inflammation are commonly observed in people who have depression. Chronic activation of the body's inflammatory response system promotes the development of depressive symptoms and induces changes in the brain and neuroendocrine function. Sauna use has been shown to reduce symptoms of depression.
"In a randomised, double-blind study on depression, a single session of whole-body hyperthermia elevating core body temperature to 101.3°F caused an acute antidepressant effect within a week and persisted for six weeks after treatment."
Evidence suggests that beta-endorphins are responsible in part for the "feel-good" response to exercise. The binding of beta-endorphins to mu-opioid receptors on nerve cells suppresses the release of pain-promoting substances in the brain. Sauna use promotes robust increases in beta-endorphins.
With benefits like these, you’ll want to book yourself in and get your sweat on at Fast Twitch’s infrared sauna.
Effects of Sauna Usage Mental focus and attention span
Two key players in cognitive and mental function are norepinephrine, a hormone and neurotransmitter produced in the brain, and prolactin, a hormone released by the pituitary gland. Norepinephrine enhances focus and attention, while prolactin promotes myelin growth, which makes the brain function faster, a critical feature in repairing nerve cell damage.
When young men stayed in a sauna that was heated to 80°C (176°F) until subjective exhaustion, their norepinephrine levels increased by 310 percent, and their prolactin levels increased by 900 percent.
Similarly, a study involving women who participated in 20-minute sessions in a dry sauna twice a week experienced a 86 percent increase in norepinephrine and a 510 percent increase in prolactin after the session.
Similar health benefits to these can be experienced from practising hot yoga as they both use far-infrared panels to heat. Read more about the health benefits of hot yoga.
Effects of Sauna Usage on Hormonal and metabolic function
Growth hormone
Sauna use promotes growth hormone release, which varies according to time, temperature, and frequency. For example, two 20-minute sauna sessions at 80°C (176°F) separated by a 30-minute cooling period elevated growth hormone levels two-fold over baseline, but two 15-minute sauna sessions at 100°C (212°F) dry heat separated by a 30-minute cooling period resulted in a five-fold increase in growth hormone.
Insulin and glucose
Insulin regulates glucose homeostasis, primarily by promoting the uptake of glucose into muscle and adipose tissue. The heat treatment specifically targeted the skeletal muscle by increasing the expression of a type of transporter known as GLUT 4, which is responsible for transporting glucose into the skeletal muscle from the bloodstream. Decreased glucose uptake by skeletal muscle is one of the mechanisms that lead to insulin resistance.
Physical fitness and athletic performance
Heat stress from using the sauna may modulate improvements in physical fitness and athletic performance by increasing endurance and maintaining or promoting gains in muscle mass.
Increased endurance
"One 30-minute sauna session twice a week for three weeks post-workout increased the time that it took for participants to run until exhaustion by 32% compared to their baseline."
How Sauna Facilitates Heat Acclimation
Heat acclimation increases plasma volume and blood flow to the heart (stroke volume).[80][81] This results in reduced cardiovascular strain and lowered heart rate for the same given workload. These cardiovascular improvements have been shown to enhance endurance in both highly trained and untrained athletes. Heat acclimation also increases blood flow to the skeletal muscles, fuelling them with glucose, fatty acids, and oxygen, reducing their dependence on glycogen stores. Endurance athletes often “hit a wall” due to the depletion of their liver and muscle glycogen stores. Heat acclimation has been shown to reduce muscle glycogen use by 40 to 50 percent compared to before heat acclimation, presumably due to increased blood flow to the muscles.
Improvements in thermoregulatory function are also observed following heat acclimation. Heat exposure activates the sympathetic nervous system, increasing peripheral blood flow and the sweat rate to dissipate core body heat. After acclimation, sweating occurs at a lower core temperature and the sweat rate is maintained for a longer period.
Effects of Sauna Usage on Muscle Mass
"A study found that daily heat treatments applied locally to muscle during 10 days of immobilisation prevented the loss of mitochondrial function, increased HSP levels, and attenuated skeletal muscle atrophy by 37% compared to a sham control group."
A small intervention study in humans found that daily heat treatments applied locally to muscle during 10 days of immobilisation prevented the loss of mitochondrial function, increased HSP levels, and attenuated skeletal muscle atrophy by 37 percent compared to a sham control group.
Heat shock proteins, described above, can prevent muscle protein damage by directly scavenging reactive oxygen species and by supporting cellular antioxidant capacity through their effects on maintaining the endogenous antioxidant glutathione. In addition, HSPs can repair misfolded, damaged proteins, thereby ensuring proteins maintain their proper structure and function.
Effects of Sauna Usage on Detoxification
Sweating facilitates the excretion of certain toxicants that bioaccumulate in the muscle, adipose tissues, and organs of humans. As described above, sauna use induces substantial sweat losses, with the average person losing approximately 0.5 kg of sweat while sauna bathing. Heavy Metals, Bisphenol A, Polychlorinated biphenyls, and Phthalate compounds are excreted through the skin via sweating. Continue reading more information about the benefits of infrared sauna for detoxification.
Keen on testing the science behind sauna usage benefits? Book Infrared & Finnish Sauna Sessions in at Fast Twitch!
