From: hubermanlab
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Heat and cold exposure are increasingly being recognized as valuable tools for enhancing both mental and physical health. Dr. Rhonda Patrick and Andrew Huberman discussed the myriad benefits and mechanisms underlying these practices in a recent episode of the Huberman Lab Podcast. Here’s a comprehensive look at how deliberate exposure to these temperature extremes can be beneficial, the biological processes involved, and practical ways to incorporate them into daily life.
Cold Exposure
Mechanisms and Benefits
Cold exposure stimulates several physiological processes that can boost health. One key mechanism is the release of norepinephrine (noradrenaline) in response to cold stress, which acts as both a hormone and neurotransmitter. This release enhances metabolism, improves mood, and even stimulates the browning of fat, which is essentially an increase in metabolically active brown adipose tissue. This browning of fat is facilitated through the activation of a gene known as UCP1 (uncoupling protein 1) and leads to increased mitochondrial biogenesis, further promoting energy expenditure via the creation of heat instead of ATP through a process called thermogenesis [02:00:02].
Protocols
Dr. Patrick typically engages in cold exposure by submerging in cold water at temperatures around 49 degrees Fahrenheit (9.4 degrees Celsius). Even brief exposures, such as 20 seconds, can trigger significant health benefits, including lasting increases in norepinephrine levels, which enhance mood and focus [01:53:20]. While more extended exposure or regular practice can stimulate the development of brown fat, which enhances metabolic function and heat production, people new to cold exposure should gradually increase their exposure to prevent shock or discomfort. This ties into the role of shivering and cold exposure in fat loss, where deliberate cold exposure has been shown to be an effective way to boost metabolism and aid in fat reduction.
Heat Exposure
Mechanisms and Benefits
Heat exposure, typically achieved through sauna use, offers numerous health benefits, including improved cardiovascular health, enhanced brain function, and increased longevity. The critical mechanism here involves heat stress, which elevates heart rates similar to moderate-intensity aerobic exercise, promoting cardiovascular health. Additionally, heat exposure is known to robustly increase heat shock proteins, which aid in protein folding and protect against cellular damage, potentially reducing the risk of neurodegenerative diseases like Alzheimer’s [02:25:03].
Protocols
The efficacy of sauna bathing or heat exposure largely depends on the duration and frequency. For instance, using a sauna for more than 19 minutes at temperatures around 174 degrees Fahrenheit (79 degrees Celsius) four to seven times per week is associated with a significant decrease in cardiovascular and all-cause mortality, as well as dementia and Alzheimer’s risk [02:22:14]. This protocol suggests a “dose-dependent” relationship where longer and more frequent sessions confer greater health benefits.
Alternatives
For those who lack access to a traditional sauna, hot baths can serve as a viable alternative, achieving similar physiological effects. Maintaining a water temperature of around 104 degrees Fahrenheit (40 degrees Celsius) for about 20 minutes can activate beneficial processes like heat shock protein expression and increased BDNF (brain-derived neurotrophic factor) which supports brain health [02:36:09].
Conclusion
Both cold and heat exposure offer simple, cost-effective ways to improve overall health. By understanding the mechanisms through which they work, such as norepinephrine release for cold exposure and heat shock protein activation for heat exposure, individuals can tailor these practices to suit their health goals. Integrating these modalities into a weekly routine offers a promising pathway to improved physical and mental well-being.
By adopting heat and cold exposure regimens, one can tap into the body’s natural resilience mechanisms, enhancing both immediate and long-term health. As always, it is advisable to consult with a healthcare provider before beginning any new health regimen, especially for individuals with pre-existing medical conditions.
Incorporating deliberate exposure to temperature extremes can potentially be a strategy for coping with change and adversity, by enhancing the body’s resilience and overall health.