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May 30, 2023 • 15min
#080 How Heat Therapy Improves Slow Wave Sleep
FoundMyFitness
In this episode, Dr. Rhonda Patrick explores the fascinating potential of heat exposure to enhance sleep quality, particularly slow wave sleep. While factors like light exposure and avoiding blue light at night are well-known for optimizing sleep, passive body heating through saunas, hot baths, or exercise may offer another powerful tool for improving sleep.
Dr. Patrick discusses the physiological mechanisms behind how heat exposure impacts sleep, including effects on hormones, neurotransmitters, and brain activity. She also provides practical recommendations for incorporating heat exposure into a sleep optimization routine.
#080 How Heat Therapy Improves Slow Wave Sleep
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Key Takeaways
- Passive body heating through methods like saunas, hot baths, or exercise may significantly improve sleep quality, particularly slow wave sleep
- Heat exposure stimulates the release of ATP, increases adenosine levels, and signals sleep-regulating cytokines like TNF-alpha and IL-1
- Sauna use can dramatically increase growth hormone and prolactin levels, which play important roles in regulating slow wave sleep
- Timing is important - heat exposure should be done 1-2 hours before bed to allow the body to cool down before sleep
- Combining exercise with heat stress may amplify the sleep-promoting effects compared to either alone
- Warm-sensitive neurons in the hypothalamus are activated by heating and promote slow wave activity
- Recommended protocols: 20 minutes in a 176°F+ sauna or 20-30 minutes in a 104°F hot bath/tub, 1-2 hours before bed
Introduction
In this episode, Dr. Rhonda Patrick explores the fascinating potential of heat exposure to enhance sleep quality, particularly slow wave sleep. While factors like light exposure and avoiding blue light at night are well-known for optimizing sleep, passive body heating through saunas, hot baths, or exercise may offer another powerful tool for improving sleep.
Dr. Patrick discusses the physiological mechanisms behind how heat exposure impacts sleep, including effects on hormones, neurotransmitters, and brain activity. She also provides practical recommendations for incorporating heat exposure into a sleep optimization routine.
Topics Discussed
Physiological Effects of Heating on Sleep (02:06)
Dr. Patrick explains how heating the body, whether through exercise or passive methods, impacts several physiological processes related to sleep:
- ATP release and adenosine: Exercise increases energy demand, leading to more ATP production and breakdown into adenosine. Adenosine accumulation in the brain promotes sleepiness.
- Sleep-regulating cytokines: Exercise stimulates production of somnogenic cytokines like TNF-alpha and IL-1, which act on brain regions to promote sleep.
- "Exercise stimulates the production of certain cytokines such as tumor necrosis factor alpha, that's also known as TNF alpha, or interleukin one or Il one. These are actually somnogenic cytokines."
She notes that while exercise has these beneficial effects, it's important not to exercise too close to bedtime, as the acute alertness and temperature increase can interfere with sleep onset.
Growth Hormone and Prolactin Effects (06:59)
Dr. Patrick discusses how heat exposure, particularly sauna use, dramatically increases levels of growth hormone and prolactin:
- Growth hormone: Sauna use can increase growth hormone 2-16 fold, depending on duration, temperature, and frequency. Effects typically last a couple hours.
- Prolactin: Sauna use can increase prolactin levels 5-10 fold. Prolactin plays a role in regulating sleep, particularly REM and slow wave sleep.
- "Regular sauna use is probably one of the most powerful stimuli that increases both growth hormone and prolactin."
She notes that combining exercise with heat stress may amplify these hormonal effects even further.
Other Factors Affecting Growth Hormone and Prolactin (10:39)
Dr. Patrick mentions other lifestyle factors that can increase growth hormone and prolactin levels:
- Exercise: Can increase both hormones, though exact quantitative effects weren't specified
- Sexual activity: Also increases both prolactin and growth hormone
She emphasizes the importance of timing these activities a couple hours before bed to allow the body to cool down before sleep.
Warm-Sensitive Neurons and Slow Wave Activity (12:09)
Dr. Patrick explains another mechanism by which heating may promote deep sleep:
- Warm-sensitive neurons in the hypothalamus are activated by increased core and skin temperature
- This activation promotes slow wave activity in the brain
- Combining heating with subsequent cooling may further enhance this effect
Practical Protocols for Heat Exposure (12:46)
Dr. Patrick provides specific recommendations for incorporating heat exposure to potentially improve sleep:
- Sauna protocol: 20 minutes in a 176°F+ (80°C+) sauna, 1-2 hours before bed
- Hot bath/tub protocol: 20-30 minutes in 104°F (40°C) water, shoulders submerged, 1-2 hours before bed
- Allow enough time to cool down before sleep
- A cool shower afterwards may help accelerate cooling
"An example of a sauna protocol could be 20 minutes in a at least 176 degree Fahrenheit sauna at least one to 2 hours before bed, allowing the body enough time to cool down before sleep."
Conclusion
Dr. Patrick concludes that passive body heating through saunas, hot baths, or exercise may be a powerful tool for improving sleep quality, especially slow wave sleep. Rather than replacing good sleep hygiene practices, heat exposure can complement them to potentially enhance overall sleep. The mechanisms involve complex interactions between hormones, neurotransmitters, and brain activity.
Key points to remember for implementation:
- Use heat exposure 1-2 hours before bed
- Allow time for the body to cool down before sleep
- Aim for 20-30 minutes of exposure
- Sauna temperatures should be at least 176°F (80°C)
- Hot bath/tub temperatures should be around 104°F (40°C)
Dr. Patrick encourages listeners to experiment with these protocols and find what works best for their individual sleep optimization. For those interested in learning more about sleep fundamentals, she recommends her interviews with sleep experts Dr. Matthew Walker, Dr. Dan Pardi, and Dr. Ashley Mason in previous episodes.
