What are the heat and cold therapy health benefits? Which are scientifically-proven? What temperature ranges are ideal and safe? For how long? At what frequency?
Let’s look into the research.
Average Body Temperature
Average body temperature is 98.6 F (37 C). However, normal body temperature ranges from 97 F (36.1 C) to 99 F (37.2 C) or more. Your body temperature varies depending on how active you are or the time of day. As you age, you tend to have lower body temperatures than younger people.
Hot Side Hot
So what happens if you heat your body above that? A sauna session increases your body temperature up a few degrees to around 102 F (39 C). Your skin temperature rises even more to 107.6 F (42 C).
Health Benefits of Heat
Saunas have been used for thousands of years to help people to unwind and relax. Around 3,000 years ago, the Mayans used sweat houses as a therapy. Traditional Finnish saunas usually use dry heat, with a relative humidity that is often between 10% and 20%. Turkish-style saunas involve a greater level of humidity. There are various types of saunas such as electric, wood burning, infrared, smoke and steam.
In large European studies, men who attended a dry sauna bathing session 2-3 times each week reduced their cardiovascular mortality rates by ~30% and men who attended a sauna session 4+ times per week reduced their risk by ~50%. Men who attended a sauna bathing session two–three times per week reduced their risk for hypertension by ~25% and men who attended a sauna session four or more times per week reduced their risk by ~45%.
Regular sauna users lowered their risk of sudden cardiac death (63%) and all-cause mortality (40%) as well as for dementia (66%) and Alzheimer’s disease (65%). Given the similar heat stress effect, other types of saunas likely confer similar benefits.
Why is there so much benefit? Chronic mental and physical stress can lead to dangerous cardiovascular conditions. Somewhat surprisingly, adding heat stress appears to counteract this physiological damage by reducing systemic inflammation. Further research is underway to establish the causal link between heat stress and beneficial cellular mechanisms.
Additionally, sauna sessions are considered helpful for diseases of inflammation, as well as for those suffering from depression and anxiety. Since saunas increase blood vessel dilation and blood flow, they are beneficial for muscle recovery after sports and for vascular health.
Another heat stress benefit, similar to why our bodies induce fever, is that numerous pathological bacteria and viruses are unable to survive increased body temperatures.
Best Sauna Temperature Settings, Duration and Frequency
Sauna bathing between 113-212 degrees Fahrenheit and relative humidity of 10-30% mimics a physiological response similar to moderate- to high-intensity cardiovascular exercise like cycling, swimming or running. Of note, saunas are not a replacement for exercise in your healthy lifestyle. Movement is still necessary for health. Avoid temperatures above 212 degrees as they are likely to cause cell and protein damage.
The American Journal of Public Health recommends limiting sauna usage to 10 to 15 minutes at a time. European research studies show benefits up to 45 minutes at a time, however, this requires gradually building tolerance to increased duration. 4-7 sauna sessions per week produced the most health benefits.
Body Heating Health Risks
Heating up your body in a sauna, hot tub or otherwise can be dangerous. Avoid this if you:
- have high blood pressure or some types of heart issues (see your physician).
- are pregnant.
- take medications which interfere with your body’s ability to regulate temperature, or medications which make you drowsy.
- are diabetic, sick, dehydrated, inebriated, dizzy, drowsy or on drugs.
- are male and actively trying to reproduce!
If you are using a sauna or hot tub, it is important to make sure it is clean! Pathogens and fungi which can survive high temperatures and infect you are dangerous. Make sure hot tubs are well-maintained or you can get hot tub rash or worse. In saunas, sit on towels to avoid contact with benches and leave if other guests are coughing or sneezing.
Cold Side Cold
The Finnish sauna tradition often ends with a plunge in freezing cold water. Skiers, snowboarders and other daring people briefly leave their outdoor hot tubs for quick plunges in the snow. However, the use of cryotherapy for benefits to health, treatment and recovery dates back centuries. Hippocrates is credited by some as the grandfather of cryotherapy. He suggested water therapy with ice and snow could ‘allay lassitude’ in reducing the depletion of energy or strength while also reducing swelling.
When you shock your body with cold, it goes into survival mode. Your blood vessels constrict.
The question is, are there actual benefits to shocking your body with cold?
Health Benefits of Cold Therapy
Blasts of cold are believed by some to relieve pain, aid exercise recovery, increase resilience and boost your mood. Which of these are supported by high quality scientific evidence?
Competitive athletes take ice baths after grueling events and tough practices, seeking to reduce muscle soreness, swelling and inflammation after exercise. These were popularized by Wim “The Iceman” Hof, a Dutch extreme athlete, who set world records related to cold exposure. He promoted his wellness program involving cold-water immersion, breath work, and commitment (willpower).
Scientists have used near-infrared spectroscopy to monitor the effects of switching back and forth from hot and cold water. The pumping effect as the blood vessels constrict and expand, boosts blood flow to deliver more oxygen and nutrients to the tissues, helping lower inflammation and increase healing.
Cold water therapy research suggests that cold water immersion blocks nerve cells that signal pain in the body. Also, the sensation of pain is reduced because submerging your body in cold water significantly decreases your level of cortisol and increases your level of norepinephrine and dopamine, making you feel good.
There are some small studies which indicate that short daily cold exposure can boost your mood, immune system and metabolism.
Cold Therapy Temperature, Duration and Frequency
Typical cold therapy routines include 3-5 minutes of 50-59 F temperatures each day. A target temperature for optimal therapeutic effects has yet to be identified. Hypothermia occurs when your body temperature falls below 95 F (35 C). Falling into water below 40 F can lead to serious injury within a few minutes.
Avoid Cold Therapy for Injuries?
There is a debate going on within medical care between different treatment standards for muscle, ligament and tendon injuries. According to major medical centers such as the Mayo and Cleveland Clinics, their standard remains with the RICE (Rest, Ice, Compression, Elevation) recovery routine, perhaps because patients temporarily feel good. However, since 2020, expert physiologists have been promoting instead, PEACE & LOVE (protection, elevation, avoid anti-inflammatory drugs, compression, and education & load, optimism, vascularization, and exercise). Icing is not in their latest treatment guideline because it disrupts inflammation, delays neutrophil and macrophage infiltration, as well as production of anabolic hormone Insulin-like growth factor (IGF-1) that sparks the next phase of the healing process in muscle repair and regeneration. In short, icing may reduce damage from over-swelling, but slows your healing process.
With minor injuries, it is likely you will fully recover either way. If you have a significant muscle, tendon or ligament injury or lingering minor injury, consult with your physician and discuss which treatment makes sense for you.
Risks and Safety Issues with Cold Therapy
Cold therapy is not appropriate for everyone, especially for those with health conditions. Cold water immersion causes cardiac stress affecting your blood pressure, heart rate, and circulation.
Deaths during cold water swims have occurred from cold exposure and heart attacks. Discuss cryotherapy risks with your physician and make sure it’s safe to immerse yourself in very cold water before doing so.
Cryopreservation or cryobanking is the process of cooling and storing cells, tissues, or organs at very low or freezing temperatures to save them for future use. Some people hope that their entire body including their brain and memories can be preserved and eventually fully restored with future technologies. Unfortunately, because of the way our bodies and brains work, this is extremely unlikely, especially with current cryopreservation techniques.
However, companies like Alcor, the Cryonics Institute and KrioRus continue to offer cryopreservation services without a plan to restore you. Also, timing your death and subsequent preservation is quite difficult. There are legal issues with using cryopreservation while still alive and it can take too long to avoid physical damage after you are dead.
Stone Cold Conclusion
Congrats on caring enough about your health to learn more about the heat and cold therapy health benefits. As your reward, enjoy this amazing 5 minute video of the world’s coolest snow sculptures.
Heat and Cold Therapy Health Benefits Conclusion
Then, boost your mood with the classic Heat and Snow Miser song, …if that’s not too much.