How would hyperthermia or heat exposure be considered an anti-aging technique?

Regular sauna use can promote longevity and prevent age-related diseases.

An article published by Dr. Rhonda Patrick encourages us to use hyperthermic conditioning such as sauna as it has the following benefits:

• Improves cardiovascular endurance
• Prevents muscle atrophy
• Improves insulin sensitivity
• Increases neurogenesis (the production of new brain cells)
• Improves memory and learning
• And probably increases longevity.

A study of 2000 middle-aged men in Finland over a 20-year period comparing frequency of sauna use with incidence of sudden death, heart disease, myocardial infarction and all-cause mortality including cancer showed the following results:

• Cardiovascular disease was 27% lower in men who used the sauna 2-3 times per week.
• 50% lower in men who used the sauna between 4 and 7 times per week, compared to men who only used it once per week. ( 1 )

One of the important conclusions was that using the sauna 2-3 times per week could reduce all-cause mortality by 24% and using it 4-7 times per week could reduce it by 40% .

Another study published in 2016 with the same group of 2,000 men, following them for 20 years, reported that using a sauna 4-7 times per week reduced dementia by 66% and Alzheimer’s disease by 65%, compared to those who used the sauna only once per week. These results were adjusted for underlying factors in these men such as age, alcohol consumption, body mass index, physical activity, social class, systolic blood pressure, smoking, type 2 diabetes, cardiac history, resting heart rate, and LDL cholesterol levels.

Heat shock proteins: an important anti-aging component 

These are a set of proteins produced by cells of both unicellular and multicellular organisms when they are subjected to an environment that causes some type of stress (es.wikipedia.org)

One of the primary functions of heat shock proteins, or HSPS, is to maintain the three-dimensional structure of proteins within the cell so that they can do their job properly under stressful situations such as exposure to ultraviolet rays from the sun, cellular damage, and the natural aging process, for example.

Natural processes in the body such as metabolism and immune function create reactive waste (reactive oxygen and nitrated species) that damage proteins, obstructing their function and causing the accumulation of senescent proteins (which are not dead, but not active either) and which contribute to aging.

The accumulation of proteins is associated with heart diseases such as heart failure, cardiomyopathy and atherosclerosis, as well as neurodegenerative diseases such as Alzheimer's, Parkinson's and Huntington's. But by producing heat shock proteins, the accumulation of these inactive proteins is prevented and, in fact, these HSPS help to repair damaged proteins.

Thus, Dr. Patrick claims that adaptation to high temperatures, such as regular use of saunas, results in more heat shock proteins under normal conditions and even more so in stressful situations such as cell and tissue injuries.

The function of FOX03 or the longevity gene

In addition to HSPS (heat shock proteins), Forkhead box 03, or Fox03, is a human protein encoded by the Fox03 gene. To better understand its relationship with longevity, a greater amount of these proteins have been detected in very old people, so it is presumed that when a person has a good number of Fox03, they have up to 2.7 times the chance of living to a century or more.

The Fox03 has several important features that make it worth boosting its production:

• Regulates many different genes resistant to the stress of aging
• Protects against DNA damage and repairs any damage found there
• It increases the expression of genes that eliminate damaged cells so that they do not accumulate and become cancer cells.
• It makes cells more resistant by increasing the expression of antioxidant genes.
• It increases cell autophagy, meaning that senescent cells (which are not dead, but are not functioning properly either) can self-destruct so that they cannot secrete inflammatory molecules that damage more cells.
• It increases the expression of genes involved in immune function so that the body can efficiently fight viruses, bacteria and cancer cells. ( 2 )

Temperature matters

The average temperature of the dry sauna used in the study mentioned above was 79°C, with water often poured over hot stones to increase humidity and sauna stays of 20 minutes or more.

It turns out that steam baths, hot tubs, infrared saunas and far-infrared saunas do not go as high, although they are still of some merit.

Temperature and duration to obtain the benefits of heat shock proteins and Fox03

Dr. Patrick recommends that, whether it is a dry or wet sauna, the temperature should be between 77 and 82°C. The duration should be between 20-25 minutes per session.

As for the weekly frequency, it can vary depending on the physical condition of the person. For example, for a person vulnerable to Alzheimer's, 4-7 times per week is recommended.

For people who want to improve their athletic fitness, it is recommended to do it after training or on days when you rest from training.

Types of sauna

Dry sauna, wet sauna, infrared sauna, far infrared sauna, inipi and temazcal

A dry sauna refers to a wood-lined room with wooden benches and a stone heater that reaches temperatures between 70 and 90°C.

In the wet sauna, water is poured onto the hot stones, producing steam that increases the humidity by 20%.

In both dry and wet saunas, heat is transferred to the body through heated air, while in an infrared sauna, heat is transmitted through thermal radiation, which is electromagnetic radiation generated by moving particles in matter, in this case, the matter is the body. Thus, an infrared sauna heats the body directly without necessarily heating the air. Although the air is heated, it does not reach the temperatures of traditional saunas.

In the inipi and the temazcal, in addition to moistening the hot stones, ancestral chants are sung according to tradition, which can take around 25 minutes and is repeated four times. Both procedures have a spiritual connotation in which the participants concentrate on a purpose that evolves during the course of the ceremony. At the end, of course, there is a feeling of relief and purification in both the physical and spiritual realms.

Other physiological adaptations that occur through hyperthermic conditioning according to Dr. Joseph Mercola are:

Improvement in cardiovascular mechanisms and lower cardiac index 5	Lower core body temperature during hard work	Increased sweat rate and sweat sensitivity as a function of increased thermoregulatory control
Increased blood flow to skeletal muscles (known as muscle perfusion) and other tissues 7	Lower risk of glycogen depletion, due to better muscle perfusion 8	Increased red blood cell count
Greater efficiency in transporting oxygen to the muscles

Safety tips and recommendations

The skin is the largest organ of elimination, but many people do not sweat regularly, thereby depriving themselves of the benefits of this natural detoxification process. Constant use of the sauna slowly restores the elimination mechanism through the skin, which can reduce the toxic load quite significantly.

Start by staying for 30 seconds and then increase by 30 seconds until you can complete about 20 minutes. ( 3 )

Avoid using the sauna alone; always go with company	Always listen to your body when deciding how much heat stress you can tolerate. If you are sick or sensitive to heat, reduce the temperature, the time you spend in the sauna, or both.
Do not use the sauna or any of the other methods if you have been drinking alcohol.	Make sure you drink plenty of pure water before and after your sauna session. To replace electrolytes, you can add a pinch of Himalayan pink salt, which is rich in natural microminerals.
Avoid using saunas during pregnancy or during menstruation days	You may want to rest, either sitting or lying down, for 10 minutes after using the sauna.