Find your temperature minimum to defeat jetlag, shift work and sleeplessness | Huberman Lab Podcast #4
This episode of the Huberman Lab Podcast focuses on sleep and wakefulness, offering advice on how to combat jet lag, offset negative effects of shift work, and improve sleep for all ages.
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The circadian rhythm, a 24-hour internal rhythm that regulates several functions, is key to understanding sleep and wakefulness. Every cell in our body has genes that ensure it follows this rhythm, and the suprachiasmatic nucleus generates a 24-hour rhythm in response to external light-dark cycles. However, artificial lights and life demands often disrupt this rhythm.
People have genetic variations that affect their sleep patterns, and deviating from a diurnal schedule can have serious health effects such as depression, amnesia, and dementia. However, the focus is on providing tools to improve sleep rather than scare tactics.
Professor Huberman recommends getting at least 100,000 lux of light before 9:00 or 10:00 AM to effectively set your circadian clock, preferably from sunlight. Even on cloudy days, being outside can provide 7,000–10,000 lux. While artificial lights can help, they are not as effective as natural sunlight. Light technologies emitting up to 930 lux are available but should be used in combination with sunlight. Additionally, looking at sunlight around sunset is beneficial.
To improve sleep, prioritize exposure to sunlight in the morning and avoid bright lights between 10 or 11 PM and 4 AM. Afternoon light adjusts eye sensitivity, allowing screens and lights to be viewed without disturbing your sleep. Prior episodes have covered tools such as red lights and blue blockers. Aim for 100,000 lux of morning light to set your circadian clock, and prepare for sleep 14 to 16 hours after waking up.
Shifting your clock with light, temperature, exercise, and food is crucial for jet lag and maintaining a local schedule. Although jet lag can shorten your life, understanding its mechanism can help control your biological system. However, there is individual variability in how people experience jet lag, and there is no simple pill or solution to get rid of it. Understanding the mechanism of jet lag can be more helpful than following a list of things to do.
Jet lag is a serious condition that can cause amnesia, fluctuations in mood, and potentially shorten one’s life. Traveling across multiple time zones can conflict with the body’s biological mechanisms that govern circadian timing. To combat jet lag, it is important to prioritize exposure to sunlight in the morning, avoid bright lights before bedtime, and shift the biological clock with light, temperature, exercise, and food. Sleeping pills should be avoided, and travelers should be cautious of accidents due to jet lag-induced disorientation, especially when traveling westward.
It is easier to adjust to a new time zone when traveling westward than eastward due to our body’s ability to stay awake longer. Jet lag is caused by travel fatigue and time zone changes, and it gets worse as we age. Regular exercise can help shift our circadian clock and make it easier to adjust. While melatonin can induce sleepiness, it can also affect hormone systems negatively. Traveling north or south doesn’t involve a time zone shift, but fatigue can still be experienced. Each person experiences jet lag differently, and some may struggle more than others.
To improve your sleep further, it’s important to understand your internal clock and how it can be shifted by changing your temperature. The temperature minimum is the point in the 24-hour cycle when your temperature is lowest, which tends to fall 90 minutes to 2 hours before your average waking time. Measuring your temperature every couple of hours for 24 hours can help find your temperature minimum. The temperature minimum can be disrupted by saunas, cold baths, intense exercise, and meals. Temperature is the signal by which your internal clock works, according to Joe Takahashi’s research.
Temperature and bright light exposure after the temperature minimum can advance your circadian clock, while light exposure before it can delay it. Finding your own temperature minimum is key, which can be done by averaging the last 3–5 wake-up times. Sleeping throughout the day and relying on alarm clocks are signs of insomnia and a lack of sleep. Finally, keep in mind that the temperature minimum is affected by changes in your wake-up time, so it’s important to be consistent.
It is important to prioritize preparation before traveling to adjust to a new time zone. Using light, exercise, and eating can shift your clock up to 3 hours per day, and eating on a local schedule is recommended for adjustment.
To improve sleep and combat jet lag, it’s recommended to eat according to the local schedule and not stick to your home meal schedule, as it can throw off your biological clocks. Skipping a meal is fine if you don’t feel like eating due to jet lag, and the temperature minimum is the best anchor point for shifting your clock. Melatonin is often used to shift the clock, but there are other more complicated ways as well. When traveling westward, the challenge tends to be different than traveling eastward as the body can stay awake longer.
To stay up later, it’s recommended to use caffeine, exercise, and sunlight to shift your sleep schedule. Avoid taking naps that last longer than intended and push past afternoon tiredness with stimulants like caffeine. Eating on the local schedule can also help adjust to a new time zone, and melatonin can be used to induce sleepiness, although its effectiveness is debated. Keep in mind that the autonomic nervous system is more wired to stay up later than to sleep earlier, so it can take time to adjust.
Melatonin can induce sleepiness but inhibits the release of hormones important for puberty. Supplementing melatonin can lead to high levels of the hormone and affect puberty in developing children. While melatonin can help induce sleepiness, behavioral interventions such as exposure to light, exercise, and temperature are preferred for improving sleep. Shifting the circadian clock can be achieved through the use of light, temperature, and exercise around the temperature minimum.
For short trips, it is best to stay on your home sleep schedule, and mechanisms can help adjust your body rhythms when they get out of whack.
When traveling, it’s recommended to stay on your home sleep schedule to minimize jet lag. Even long trips may not throw off your internal clock by more than a couple of hours, but after 48 hours, you may start to experience more significant jet lag. Transit time is also a factor to consider when trying to maintain your home schedule. Bright light can help regulate sleep-wake cycles when traveling, and using a light pad in your hotel room can help you wake up when you want. Eye covers can also be helpful for blocking out light and aiding sleep.
Light and dark devices can be useful in regulating sleep while traveling, and bringing them along can maintain your home sleep schedule. It’s also suggested to be outside during the rising phase of your temperature, and to avoid exposing yourself to too much light in the window before temperature minimum in a new location. Consistent exercise and creating a dark environment at night can also aid in regulating sleep. Getting bright light in your eyes during the day is important, and disrupted sleep can have long-lasting effects.
Shift work can cause jet lag without any travel and have negative effects on sleep and health. Strategies to minimize shift work jet lag include minimizing light exposure during sleep and scheduling regular exposure to natural light. Some companies are implementing changes to reduce the effects of shift work on employees, but further research is needed to fully understand the impact of shift work on health. Light can impact both the psyche and the body, making it important to prioritize healthy light exposure habits.
For shift workers and those under shelter-in-place rules, it is common to sleep during the day. Staying consistent with a shift schedule for at least 14 days is crucial for overall health, and swing shifts can be detrimental to health parameters and disrupt the dopamine system. Light exposure during shifts is a matter of personal choice, but it is important to avoid bright light exposure after a night shift and use blue blockers to dim screens for better sleep. Getting light exposure after waking up from a night shift depends on an individual’s temperature minimum, and temperature minimum is an important factor for scheduling light exposure and sleep for shift workers.
To optimize sleep and wakefulness, it is important to understand the relationship between temperature rhythm and light exposure. People should aim to decrease light exposure when their temperature is decreasing and increase light exposure when their temperature is increasing. Each individual has a unique internal temperature rhythm, making it crucial to measure and understand it. A circadian body temperature measurement device could be useful. Knowing one’s temperature minimum is especially important for shift workers, who should maintain a consistent schedule based on their unique temperature rhythm.
While sleep debt should be taken seriously, being neurotic about it is unnecessary as biological systems are forgiving. It is unclear what the consequences of missed sleep are, and recovering missed sleep is not possible.
Using NSDR protocols such as hypnosis and yoga nidra can improve sleep quality. These protocols involve using the body to calm the mind and can be done during the day or in the middle of the night. Meditation is also recommended for better sleep. The importance of controlling sleep and circadian rhythms in people of all ages, from babies to the elderly, is emphasized.
To optimize sleep for babies, it is important to understand that their melatonin levels initially start high and decrease as they grow. Babies have sensitive eyes and are naturally averse to bright light. Their ultradian rhythms change quickly, and adjusting the overall environment can help encourage sleep. Keeping the room slightly colder during sleep and warmer during awake times can also be helpful. Siblings and the nursery environment are factors that can impact sleep patterns.
To optimize sleep, it is recommended to avoid extreme temperatures and maintain autonomic regulation. Understanding the relationship between calm and deep sleep is also important, and sleep can be captured in batches if necessary. Non-sleep deep rest protocols and mirroring the baby’s sleep cycle can also be helpful for recovery. It is advised to avoid administering melatonin to kids for longer sleep blocks.
To optimize sleep, it is recommended to aim for sleep cycles that match 90-minute ultradian cycles rather than a continuous long stretch of sleep. Fractured sleep matching ultradian cycles is beneficial for better sleep and growth, but waking up in the middle of an ultradian cycle can be hard for parents and kids. Morning and evening sunlight can help anchor the circadian clock during disrupted sleep patterns, and NSDR protocols can help with staying calm during disrupted sleep patterns. Try to get sleep whenever possible and use artificial light if morning and evening sunlight are not available, especially for those caring for sick loved ones or experiencing chaotic sleep patterns.
To optimize sleep for adolescents, it’s important to prioritize the duration of their sleep and understand their tendency to wake up later and go to sleep later due to changing bodies during puberty. Regular exposure to morning and evening sunlight can help maintain a good circadian rhythm. Some schools are also starting classes later to support this late-shifted rhythm and extended sleep phase. To avoid disrupting their circadian rhythm, it’s best to avoid waking adolescents up from sleep, especially during their circadian dead zone. Giving adolescents some flexibility in adjusting their sleep schedules is also important.
One recommendation for optimizing sleep is to turn on the lights in a teenager’s room before they wake up, which can help them get more sleep and go to bed earlier. This can also be helpful for adults by using a timer for the lights to go on before waking up. The mechanism is core and not numerous, and although not part of a standard study, it seems to work for some parents. Additionally, light exposure through closed eyelids after the temperature minimum can make people want to sleep earlier. The benefits for elderly individuals are not mentioned in the text.
To optimize sleep for elderly individuals, it is important to understand that their melatonin levels can become chaotic. Lifestyle factors can also affect rates of aging. Elderly people need natural light and should avoid artificial light, and melatonin might be helpful for those with sleep problems. A regular schedule and natural light are important for adjusting sleep, and exercise can help, even if getting outside is difficult. It is recommended that individuals talk to their physician for personalized advice.
There are various supplements that can aid in improving sleep besides melatonin, including magnesium and theanine. Behavioral protocols should also be prioritized for good sleep. Apigenin can act as a hypnotic and 5-HTP and L-tryptophan can help transition to sleep, but may not be suitable for everyone. Additionally, there may be ways to make sleep more compact.
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