Andrew Huberman: Sleep, Dreams, Creativity, Fasting, and Neuroplasticity | Lex Fridman Podcast #164 | Summary and Q&A

February 28, 2021
Lex Fridman Podcast
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Andrew Huberman: Sleep, Dreams, Creativity, Fasting, and Neuroplasticity | Lex Fridman Podcast #164


Neuroscientist Andrew Huberman explains the importance of sleep, the mechanisms behind sleepiness, and the impact of circadian rhythms on wakefulness.

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Key Insights

  • šŸ”¬ The accumulation of adenosine in the brain causes sleepiness, while the circadian cycle affects how sleepy we feel at different times of the day.
  • šŸ˜“ Sleep is essential for bodily functions like metabolism and reproduction, and the optimal temperature for sleep is around 2-3 degrees lower than normal body temperature. ā° Consistency in total sleep duration is more important for performance than the total amount of sleep obtained.
  • šŸ›Œ Napping for around 20-30 minutes can be beneficial, especially if aligned with 90-minute ultradian cycles. Remember to elevate your feet or use relaxation techniques if you have trouble falling asleep.
  • šŸ½ļø Eating can make you sleepy due to increased blood flow to the gut, so be mindful of when and what you eat during your sleep schedule.
  • šŸ§  Focusing on gratitude and positive anticipation can improve sleep quality, even with reduced sleep duration. Practicing non-sleep deep rest or using hypnosis can also be restorative.
  • ā™‚ļø During intense physical activities, such as running, try using double inhales and exhales to maintain heart rate variability. Nasal breathing is generally preferred, but can be difficult during intense exercise.
  • šŸ˜” Anger can provide motivation and fuel during physical exertion, but it's important to find a balance and use other emotions like love and joy to maintain a positive mindset.
  • šŸ’­ The mind plays a significant role in physical performance, and focusing on positive thoughts and rituals can enhance effort and enjoyment during challenging tasks.
  • šŸŒ™ Intermittent fasting, like fasting for 16 hours and having an 8-hour eating window, can have various benefits including improved mood and performance. Extended fasting for 24-72 hours can also be effective, but it's important to listen to your body and consult with a healthcare professional if attempting longer fasts.
  • šŸ’” Anecdotal evidence suggests that fasting during long-duration challenges, combined with a positive mindset, can enhance performance and provide a sense of accomplishment.


the following is a conversation with andrew huberman his second time in the podcast he's a neuroscientist at stanford a world-class researcher and educator and now he has a new podcast on youtube and all the usual places called hubermann lab that i can't recommend highly enough quick mention of our sponsors master class online courses four sigmatic... Read More

Questions & Answers

Q: Why is it important to understand the mechanisms behind sleepiness?

Understanding the mechanisms behind sleepiness helps us improve our sleep hygiene and develop strategies to better manage our sleep and wakefulness levels.

Q: Can you explain the relationship between the accumulation of adenosine and sleepiness?

Adenosine accumulates in our brain as we stay awake, and it binds to receptors, creating a feeling of sleepiness. The longer we are awake, the more adenosine accumulates, leading to a greater sense of sleepiness.

Q: How do circadian rhythms contribute to sleepiness and wakefulness?

Circadian rhythms, influenced by temperature oscillations, determine our sleep-wake cycles. The circadian cycle aligns with the 24-hour spin of the Earth and regulates when we feel sleepy or awake based on the temperature of our bodies.

Q: Are there any strategies to optimize sleep duration and quality?

Staying on a regular sleep schedule, monitoring light exposure, and paying attention to the timing of bright light exposure can help optimize sleep duration and quality. Additionally, understanding individual sleep preferences, such as napping or non-sleep deep rest, can be beneficial for overall sleep performance.


This conversation with neuroscientist Andrew Huberman explores the topic of sleep. They discuss the reasons why humans need sleep, the impact of adenosine accumulation and circadian cycles on sleepiness, the role of temperature in sleep regulation, and the importance of sleep consistency. They also touch on the optimal temperature for sleep and the benefits of napping. The conversation concludes with a discussion on the upcoming challenge of running 48 miles every four hours with David Goggins, and potential strategies for managing sleep during the challenge.

Questions & Answers

Q: Why do humans need sleep?

The accumulation of adenosine and the circadian cycle both contribute to feelings of sleepiness, regardless of time of day. Adenosine binds to adenosine receptors and creates the sensation of sleepiness. The circadian cycle, which is guided by temperature oscillations, can also impact how sleepy or awake we feel.

Q: How do temperature oscillations affect sleepiness?

The circadian cycle, marked by temperature oscillations, plays a role in sleepiness. Our lowest temperature point typically occurs around 3-4 a.m., and our temperature starts to rise as we wake up in the morning. This temperature rhythm helps regulate our sense of sleepiness or wakefulness.

Q: What is the relationship between temperature and the circadian cycle?

The circadian cycle and temperature rhythms are interconnected. The master circadian clock synchronizes 24-hour oscillations in gene expression across our body. Temperature acts as the effector of the circadian clock and helps maintain synchronized rhythms throughout our various organs and tissues.

Q: How does the alignment of sleep with the sun's cycle impact our health?

It is generally beneficial for humans to follow a diurnal schedule, waking up when the sun is out and sleeping when it is dark. Diurnal individuals tend to have better immune function and metabolic health compared to nocturnal individuals. Different animal species have evolved waking and sleeping patterns based on predation and prey dynamics during particular times of day.

Q: What factors contribute to the feeling of sleepiness?

Adenosine accumulation, the circadian cycle, and overall temperature play roles in determining our level of sleepiness. Adenosine buildup makes us feel sleepy, while the circadian cycle and temperature influences affect how sleepy or awake we feel in different parts of the day.

Q: Is there an optimal temperature for sleep?

The optimal temperature for sleep is generally around 2-3 degrees lower than our waking body temperature. A decrease in body temperature aids in transitioning to deep sleep and maintaining sleep throughout the night.

Q: How does napping affect sleep and wakefulness?

A nap of around 20-30 minutes during the day can be beneficial. It avoids entering rapid eye movement (REM) sleep and allows for increased alertness and productivity. Individuals can also try relaxation techniques and hypnosis to achieve deep restorative states even without sleep.

Q: Is it better to have consistent sleep patterns or prioritize the total duration of sleep?

Consistency in total sleep duration is more important for performance than simply attempting to get more sleep. Establishing a regular sleep routine and waking up after a complete 90-minute ultradian cycle can be beneficial for cognitive and motor functioning.

Q: Can lost sleep be recovered?

Recovering sleep is possible by focusing on getting enough rest, even if the sleep duration is reduced. Falling asleep during the day might indicate sleep deprivation, while fatigue without falling asleep usually suggests other forms of physical tiredness. Gratitude and positive anticipation about the next day's events can enhance sleep quality even with limited sleep.

Q: What strategies can be used to manage sleep during a physically demanding challenge?

Two approaches could be considered for managing sleep during the challenge. One option is to push through the fatigue and not to expect much sleep. This eliminates the stress of not being able to sleep and allows for potential bonus sleep if it happens naturally. Another approach is to aim for 90-minute naps during the intervals between running sessions, focusing on optimizing sleep within those short periods.

Q: How can mental sharpness be maintained during physically demanding activities?

While physically demanding activities can be mentally draining, tapping into the power of gratitude and focusing on meaningful goals can help maintain mental sharpness. Additionally, strategies like being fasted and staying hydrated can increase alertness levels.

Summary & Key Takeaways

  • Sleep is necessary due to the accumulation of adenosine in the brain, which creates a feeling of sleepiness.

  • The circadian cycle, influenced by temperature oscillations, also contributes to sleepiness and wakefulness.

  • The effects of sleep deprivation can be mitigated through tactics such as staying awake for shorter periods, monitoring light exposure, and optimizing sleep duration.

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