Using Science to Optimize Sleep, Learning & Metabolism

Name: Using Science to Optimize Sleep, Learning & Metabolism
Uploaded: 2021-01-18T13:00:25.000Z
Duration: 3 h 22 min 26 s

Welcome to the Huberman Lab Podcast

Overview: Introduction to the podcast and sponsors.

Sponsors

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Office Hours

Overview: Discussion of office hours format and questions received.

Questions

Questions asked often: Questions asked often and with a thumbs up.

Questions to expand on topics: Questions to expand on topics covered previously.

Role of Moonlight and Fire in Circadian Rhythms

Overview: This section discusses the role of moonlight, fire, and candle light in circadian rhythms. It explains what a lux is and why these sources of light do not reset the circadian clock at night.

Light Intensity

One lux equals the illumination of one square meter surface at one meter away from a single candle.

6,000 lux of light intensity is equivalent to 6,000 candles all with their light intensity shown on one square meter from one meters distance away.

Moonlight, Fire, and Candle Light

Moonlight, fire, and candle light do not reset the circadian clock at night.

Melanopsin ganglion cells adjust their sensitivity across the day and respond best to the blue-yellow contrast present in the rising and setting sun.

Enjoying fireplaces and candle lights are perfectly safe without disrupting the circadian rhythm, as long as they are not too bright.

Red Light and its Effects on Mitochondria Function

Overview: This section discusses the potential benefits of red light on mitochondrial function, as well as the importance of timing and intensity when using red light.

Red Light and Mitochondrial Function

Red light is used in a number of commercial products that claim to improve mitochondrial function.

Studies on the effects of red light on the visual system have been published in journals with varying levels of peer review and stringency.

A study from Glen Jeffrey's Lab at the University of College, London showed that viewing red light for a few minutes each morning can have positive effects on mitochondria in photoreceptors, which tend to decline in function with age.

Most questions about red light are related to its use later in the day, which may not stimulate melanopsin retinal neurons that wake up the brain and circadian clock.

If using red light later in the day, it should be very dim in order to avoid waking up the body and brain.

Red light is convenient because it can be seen well, but it is not necessary.

Blue light should be used in abundance early in the day, but avoided later in the day.

Blue Light and Circadian Rhythms

Overview: This section discusses the science behind blue light and its effects on circadian rhythms. It explains why blue blockers may not be as effective as initially thought, and why light delivered to other orifices of the body may not be as beneficial as claimed.

Blue Light and Melanopsin Retinal Cells

Melanopsin retinal cells react to blue light, which led to the belief that blue blockers would be beneficial for preventing resetting of the circadian clock at night.

However, when these cells are taken out of the eye and put in a dish, they respond only to blue light. In the eye, they also respond to other wavelengths of light due to input from photo receptors.

Therefore, blue light is not the only stimulus that will trigger these cells. Blue light during the day is great, but at night it is best to avoid bright lights of any color.

Light Delivered to Other Orifices

Light delivered to the ears, roof of the mouth, or up the nose may not directly benefit setting circadian rhythms.

To distinguish between what is commonly called the placebo effect and more important ways to think about any manipulation, the difference between modulation and mediation should be considered.

Putting lights up the nose is not recommended, as it may modulate biology by way of the stress hormone released.

Virtually anything we face shifts our circadian rhythm if it is different and dramatic enough.

The question is whether the light delivered is actually tapping into the natural biology of the system being manipulated.

Distinguish between real biology and hacks, as a hack is using something for a purpose for which it was not intended.

There are commercial products claiming that light delivered to the ears or elsewhere can adjust wakefulness or sleep, but these studies are often not published in blue ribbon journals.

If someone disagrees with this stance, they can send a peer-reviewed paper published in a quality journal about light delivered anywhere but the eyes of humans that can mediate circadian rhythms, wakefulness, etc.

Light Effects on Circadian Rhythms

Overview: This section discusses the effects of light on circadian rhythms, and how to adjust for heat when using light to set your circadian clock.

Light Reception in Humans

Proper controls should be done when adjusting for heat to shift circadian rhythms.

Light to the eyes is where these light effects work in humans and other animals.

Humans do not have extra ocular photo reception.

Be mindful of the difference between modulation and mediation when using light to set your circadian clock.

Behavioral Tools

A mediating process through a hard wired or long-standing biological mechanism is where you're going to see powerful effects over time.

Favor behavioral tools and zero cost tools first before plugging in and swallowing things.

Light Through Windows

Setting your circadian clock with sunlight coming through a window will take 50 to 100 times longer.

Use the free app Light Meter to measure lux levels outside and inside with and without a window open.

Lux levels do not scale linearly, so don't assume that if lux levels are halved, you need to look for twice as long.

Prescription Lenses and Contacts

It is perfectly fine to wear prescription lenses and contacts.

The lenses worn in front of the eyes are designed to focus the light onto the neural retina.

Looking through a window diminishes the effect because it is not optically perfect to bring the image and the light onto the retina.

Photon Activation and Circadian Dead Zone

Overview: This section discusses the importance of photon activation early in the day, the circadian dead zone, and how to protect against the sensitivity of light at night.

Light Exposure Early in the Day

Early in the day, when the sun is low in the sky, you can sum or add photons.

This brief period of time is when your brain and body are expecting a morning wake up signal.

If it's not that bright outside, turn on the lights really bright and overhead lights in particular.

At least for the first few hours of the day, you can continue to some or add photon activation of the cells in the eye and the brain.

Circadian Dead Zone

In the middle of the day, once the sun is overhead, or even if you stay inside all morning, you're in the circadian dead zone.

It doesn't matter if you get a ton of artificial light or even sunlight, you're not going to shift your circadian clock.

Protecting Against Sensitivity to Light

To protect against the sensitivity of light at night, look at the setting sun and watch the evening sun, even if it's not crossing the horizon around the time of sunset.

This will adjust down the sensitivity of the system and allow you to watch a little bit of Netflix in the evening.

Seasonal Changes

Every cell in your body is tuned to the movement of the planet relative to the sun.

Depending on where you are in the world, Northern hemisphere, Southern hemisphere, at the equator or closer to the poles, the days and nights are going to be different lengths.

This translates to real biological signals that impact everything from wakefulness and sleep times but also mood and metabolism.

Light inhibits melatonin powerfully. If days are long and getting longer, that means melatonin is reduced.

If days are getting shorter, light can't inhibit melatonin as much, and the total amount of melatonin is less.

Understanding Seasonal Effects on Mood and Metabolism

Overview: This section discusses the effects of melatonin on diurnal animals, such as humans, and how it can affect mood, reproduction, metabolism, and other bodily functions. It also explains how light exposure can be used to regulate melatonin levels and how this can be used to optimize mood and metabolism. Finally, it touches on the role of serotonin and dopamine in regulating mood and behavior.

Effects of Melatonin

Melatonin is a hormone that is released in response to external day length and is responsible for regulating diurnal animals' sleep-wake cycles.

In general, the longer the melatonin signal, the more depressed our systems tend to be. This can manifest in reduced reproduction, metabolism, and mood, as well as slower turnover rates of skin and hair cells.

Some people are very strongly tied to the seasons and may experience clinical depression in winter, for which light therapy can be helpful.

Suicide rates tend to be highest in the spring, which is thought to be related to people emerging from the depths of low energy.

Light Exposure and Melatonin

While it may seem logical to get as much light as possible to reduce melatonin levels, this is not recommended as melatonin also has important effects on the immune system and brain.

Everyone needs to figure out for themselves how much light they need early in the day and how much light they need to avoid late in the day in order to optimize their mood and metabolism.

Role of Serotonin and Dopamine

Melatonin is synthesized from serotonin, which is associated with feelings of well-being provided to proper levels.

Serotonin does not stimulate action, but rather quiescence and calm.

Dopamine, on the other hand, is a reward feel good neuromodulator that stimulates action.

Exercise and Neuromodulators: Effects on Sleep Quality (#t=2042)

Overview: This section discusses the effects of exercise and neuromodulators on sleep quality. It covers the differences between epinephrine and adrenaline, the two forms of exercise (cardiovascular and resistance), and the benefits of aerobic exercise for sleep.

Cardiovascular Exercise

Cardiovascular exercise is a form of exercise that involves repeating a movement over and over continuously. Examples include running, biking, rowing, and cycling.

Resistance Exercise

Resistance exercise is a form of exercise that involves moving and lifting progressively heavier weights. It is an anaerobic type of exercise.

Benefits of Aerobic Exercise

Most studies of exercise have looked at aerobic exercise because it is easier to get rats and mice to do. Aerobic exercise has been found to have numerous benefits for sleep, including improved sleep quality and duration.

Optimizing Performance and Injury Reduction Through Exercise Timing

Overview: This section discusses the importance of timing exercise to optimize performance and reduce injury. It also covers the effects of light exposure and neural plasticity on wakefulness and sleep.

Timing Exercise

There is individual variation in the optimal time to exercise, but there are a few windows that have been identified in the exercise science and circadian literature.

These windows include 30 minutes after waking, three hours after waking (which correlates with the rise in body temperature), and 11 hours after waking (when temperature tends to peak).

It is important to find what works best for you, but exercising first thing in the morning can help develop an anticipatory circuit that will lead you to want to wake up at the same time each day.

Sleep Need and Exercise

If you are not feeling rested and recovered from sleep, it is possible that the intensity of your exercise in the proceeding two or three days was too high.

It is important to look at the literature from International Journal Chronobiology and journal Biological Rhythms to assess these parameters.

Neural Plasticity

Neural plasticity is the brain and nervous system's ability to change in response to experience.

Some of this plasticity is short-term and some is more long-term.

An example of this is if you eat on a very tight schedule, after a few days you will start to anticipate those meal times and feel hungry before them.

Neuroplasticity and Learning in Sleep

Overview: This section discusses the concept of neuroplasticity and how it can be used to improve learning and retention. It also provides tips on how to incorporate protocols to increase plasticity into one's daily routine.

Sleep-Dependent Plasticity

Sleep is an important factor in learning and memory formation.

Studies have shown that when a stimulus (e.g. odor or tone) is presented during sleep, rates of learning and retention are significantly increased.

Neuroplasticity can be accessed in sleep to improve rates of learning and depth of learning from the previous day.

Non-Sleep-Dependent Plasticity

Non-sleep deep breaths can be done without sleeping to improve rates of learning and depth of retention.

Implementing Protocols

A study published in the journal Science found that when a particular odor or tone was played while subjects were learning, and then again during their sleep, rates of learning and retention were significantly greater.

Subjects were presented with a screen containing different objects in different locations.

The same odor or tone was played while the subjects were sleeping in different stages of sleep (non-REM and REM).

It does not appear that the sensory modality (odor, auditory tone, or tactile stimulation) matters.

To implement this protocol, one could play a metronome or particular music while learning, and then have it playing faintly while sleeping.

Neuroplasticity and Dreams

Overview: This section covers the topics of neuroplasticity and dreams, including how to remember dreams better, the meaning of dreams, sleep paralysis, and the effects of marijuana on sleep.

Neuroplasticity

To remember dreams better, set an alarm to wake up in the middle of a 90 minute cycle which is occupied almost exclusively by REM sleep.

The meaning of dreams is controversial, with some believing they have strong meaning and others believing they are just spontaneous firing of neurons.

Good data shows that when learning spatial environments, there is a replay of those environments in sleep.

Dreams

We are paralyzed during sleep so we don't act out our dreams.

Sleep paralysis occurs when atonia intrudes into the wakeful state.

Marijuana smokers report higher frequency of sleep paralysis.

Non-sleep deep rest (NSDR) and short 20 minute naps can access neuroplasticity and increase rates of learning.

Non-Sleep Deep Rest Accelerates Learning

Overview: This section discusses the study published in Cell Reports that showed that 20 minute naps or light sleep of a sort of non sleep deep rest taken immediately after or close to learning can accelerate learning to a significant degree. It also provides resources for free yoga nidra and hypnosis protocols.

Non-Sleep Deep Rest

A study published in Cell Reports last year showed that 20 minute naps or light sleep of a sort of non sleep deep rest taken immediately after or close to learning can accelerate learning to a significant degree.

This is a cost-free, drug-free way of accelerating learning without having to get more sleep.

It is recommended to incorporate 20 minutes of non sleep deep rest per every 90 minutes of ultradian learning cycle.

Links to two different yoga nidra and hypnosis protocols from Stanford Psychiatry Department are provided in the caption on YouTube.

Hypnosis

Hypnosis brings together the alert focused wakeful state and the deep rest where the actual reconfiguration of the neurons and synopsis takes place.

Hypnosis requires some guidance from a script or from a trained hypnotist.

Hypnosis seems more about modulating the circuits that underlie state as opposed to specific information, although there may be certain forms of hypnosis that could increase retention and learning of specific information.

Nootropics, AKA smart drugs, is a big topic that requires thoughtful consideration.

Memory and Creative Thinking

Overview: This section discusses the importance of memory and creative thinking in learning, as well as the need for specificity when it comes to nootropics.

Memory

Memory is necessary for creative thinking, but not sufficient.

A knowledge base is needed to access raw materials for creativity.

Memory alone is not enough; one must also be able to task switch and develop strategies.

Nootropics

Nootropics are not specific enough to engage cognitive algorithms.

Nootropics cannot bypass the need for sleep and deep rest.

Nootropics can help with focus and activating plasticity from learning.

Most nootropics include stimulants like caffeine.

Stimulants can increase focus up to a certain point.

Most nootropics also include compounds that increase acetylcholine.

An off switch is needed to avoid crashing into lopsided sleep.

Nootropics tend to use a shotgun approach which may not be useful for long-term learning and memory.

Modafinil and armodafinil are stimulants that can improve learning and memory.

Overview of Stimulants and Nootropics

Overview: This section provides an overview of stimulants and nootropics, their potential for addiction or habit forming, and the potential metabolic effects they can have.

Stimulants

Stimulants are drugs that can be far less expensive than their generic versions.

Stimulants can have the potential for addiction or can be habit forming, as well as create metabolic effects by disruption to insulin receptors.

Examples of milder stimulants that act as nootropics include alpha GPC and Gingko, although Gingko can give some people vicious headaches.

Magnesium Threonate

Magnesium threonate is one of the more bioavailable and useful for sleep supplements, but it should be taken with caution and run by a doctor.

Magnesium threonate should be taken 30-60 minutes before sleep, as it is designed to make you sleepy.

It does not need to be taken with food, but some people may experience stomach issues with it.

Apigenin

Apigenin increases enzymes associated with GABA metabolism, which is an inhibitory neurotransmitter.

Apigenin is a derivative of camomile and works by increasing chloride channels rather than sodium ions.

Other related compounds that impact the GABA system and increase GABA include passion flower.

Apigenin and passion flower are found in many supplements designed to increase sleepiness and should be taken with caution.

Understanding the Rationale of Taking Supplements

Overview: This section discusses the importance of being thoughtful when taking supplements and explores the potential risks associated with self-experimentation.

Exploring Supplements

Understand the rationale behind taking supplements such as Macuna Purina or L-DOPA to increase dopamine.

Consider the potential risks associated with taking supplements like Al tryptophan or five HTP, which are precursors to serotonin.

Be aware that what works for one person may not work for another.

The Role of Temperature in Sleep

Temperature plays an important role in accessing sleep, staying asleep, and wakefulness.

Understand the importance of conducting both loss of function and gain of function experiments.

Be aware that a variety of factors can affect circadian rhythms, including light, exercise, and food.

Temperature and Circadian Rhythm

Overview: This section discusses the relationship between temperature and circadian rhythm, and how they are linked metabolically, biologically, and atmospherically. It also explains how temperature can be used to set the circadian rhythm, and how changes in temperature can shift the circadian rhythm.

Temperature Oscillation

Temperature oscillates from high to low.

Normal temperature range is no longer considered to be 96.8°F.

Fever is typically associated with temperatures of 100-103°F.

Temperature oscillation is endogenous and rhythmic.

Temperature Entrainment

Temperature oscillation is anchored to a pattern of being lowest at 4:00 AM and increasing again around 4-6:00 PM by way of entrainment or matching to some external cue, usually light or exercise.

Temperature can quickly become uninterested or fall out of entrainment.

Temperature and Day Length

Temperature and day length are linked metabolically, biologically, and atmospherically.

As days get longer, it tends to be hotter out. As days get shorter, it tends to be colder outside.

Temperature and Circadian Rhythm

Setting the circadian rhythm properly will cause temperature to fall into a regular rhythm.

The willingness to exercise and engage in any kind of activity is greatest when the rise in temperature is steepest (30 minutes after waking and 3 hours after waking).

Temperature peaks generally 11 hours after waking.

Light enters the eye and triggers activation of melanopsin cells, which then triggers activation of the super charismatic nucleus, the master circadian clock.

The master circadian clock informs all the cells and tissues of the body and puts them into a nice cohesive rhythm by secreting a peptide and synchronizing the temperature under which those cells exist.

Temperature is the effector of the circadian rhythm.

Changes in temperature, especially by way of exercise, can shift the circadian rhythm.

Cold showers and ice baths can also shift the circadian rhythm.

Benefits of Ice Baths

Overview: This section discusses the benefits of taking an ice bath, including its effects on thermogenesis, circadian rhythm, and melatonin production.

Thermogenesis

Taking an ice bath can lead to a rebound increase in thermogenesis.

The direction of the shift in circadian rhythm depends on whether the ice bath is taken during the day or late at night.

If taken after 8:00 PM, the ice bath will make the day longer.

Circadian Rhythm

Increasing body temperature by taking an ice bath or cold shower early in the day will phase advance the clock and make it easier to wake up earlier the next day.

Cold exposure can trigger the release of melatonin, which can help with falling asleep.

Mood and Stress Mitigation

Calming oneself while taking an ice bath or cold shower can help mitigate stress and improve mood.

Paying attention to an external stimulus can be helpful in calming the autonomic nervous system.

Further Reading

For further reading on the role of temperature in circadian rhythms, Joe Takahashi's work can be found by Googling his name.

Cold Exposure for Stress Inoculation

Overview: This section discusses the use of cold exposure for stress inoculation and raising one's stress threshold. It also explains how cold exposure is used in military stress inoculation, such as the Navy SEALs' BUD/S test.

Using Cold Exposure for Stress Inoculation

Cold exposure can be used to raise one's stress threshold and help them tolerate heightened levels of real life stress.

The goal is to suppress the activation of the sympathetic nervous system, which involves resisting the shiver response.

Cold exposure is used in a variety of forms of military stress inoculation, such as the Navy SEALs' BUD/S test.

Using Cold Exposure for Fat Loss and Thermogenesis

If you're interested in using cold exposure for fat loss and thermogenesis, you want to do the exact opposite thing and shiver away.

A paper published in Nature two years ago showed that cold induced shiver activates the release of a chemical in the body called succinate.

Succinate travels in the bloodstream and activates a particular category of fat called brown fat, which increases metabolism and causes fat burning.

Shifting Circadian Rhythm with Temperature

Temperature is the effector of circadian rhythms, while light is the trigger.

If you want to use the ice bath or cold shower to increase metabolism, shiver away.

If you want to use the ice bath or cold shower to stress inoculate, resist the shiver and learn to stay calm.

You can also shift your circadian rhythm with eating by getting onto the local meal schedule.

Food and Neurotransmitters

Overview: This section covers the relationship between food, neurotransmitters, sleep, wakefulness, and mood. It explains how certain foods can influence neuromodulator levels, as well as the impact of food volume on wakefulness.

Food Content

Nuts and meats, particularly red meats, are rich in tyrosine, which is the precursor to dopamine and norepinephrine.

Tryptophan is the precursor to serotonin and comes from the foods we eat.

Tyrosine and tryptophan are circulated to different cells and tissues, but enzymes and biochemical pathways also regulate how much tyrosine is converted into dopamine.

Food Volume

Eating a lot of anything can cause drowsiness due to the stomach becoming distended and diverting blood from other tissues.

Fasting states are associated with more alertness, while fed states are associated with more quiescence and relaxation.

Foods that are rich in tryptophan include white meat, turkey, and complex carbohydrates.

Experimentation

Experimenting with carbohydrate-rich meals can help access deeper sleep.

Low-carb/fasted/ketogenic diets tend to increase epinephrine, norepinephrine, adrenaline, and dopamine, leading to more wakefulness.

Carbohydrate-rich meals tend to increase tryptophan, serotonin, and lethargy.

Croissants are a favorite food for increasing tryptophan and relaxation.

Eating and Metabolism

Overview: This section discusses the effects of food on metabolism, wakefulness, and circadian rhythm. It also covers the effects of different types of food on neuromodulators, eating induced thermogenesis, blood sugar levels, and volume of food.

Carbohydrates and Metabolism

Carbohydrates should be eaten at one time a day as it relates to metabolism.

This may change depending on how hard someone works out and depletes glycogen.

Food Effects

Eating induces thermogenesis, an increase in metabolism and body temperature.

This is greatest for amino acid rich foods like meats, but other types of foods can also have an effect.

Starchy carbohydrates, white meat, and fish can increase tryptophan and serotonin, leading to more lethargic states and calm.

Meat, nuts, and some plant-based foods are high in tyrosine and can increase dopamine, norepinephrine, and epinephrine, leading to alertness.

Volume of food can also affect wakefulness, with less food in the gut correlating with wakefulness.

Eating early in the day tends to shift the circadian rhythm earlier, while eating late in the day tends to make people want to sleep later.

Eating healthy foods is important, but meal schedules vary from person to person.

Sex Differences in Neurotransmitter Phenotypes and Sleep/Temperature Rhythms

Overview: This section discusses the differences between sexes in terms of neurotransmitter phenotypes, sleep rhythms, and temperature. It also covers the National Institutes of Health's mandate to include sex as a biological variable in studies, and the potential impact this could have on health practices.

Sex Differences

Sex differences are related to XX, XY chromosomes, XYY in some cases, and double X chromosomes.

Genetic makeup is crystal clear when it comes to sex differences.

The National Institutes of Health made it a mandate to include sex as a biological variable in studies.

This has revealed important sex differences that could have powerful impacts on health practices, response to drugs, and response to different sleep schedules.

Pregnancy and Childbirth

Pregnancy and childbirth can cause a range of endocrine and neuro effects.

These topics will be explored in more depth with the help of experts.

Experiment

Four simple parameters can be recorded to see how one is doing with sleep and wakefulness: sunlight exposure, meals, exercise, and non-sleep deep rest protocols.

A suggested record keeping scheme includes W for waking, SL for sunlight, a check or X for exercise, and an I for meals.

This is not designed to make one neurotically attached to tracking all behaviors, but rather to provide insight into one's sleep and wakefulness.

Understanding Sleep Patterns

Overview: This section discusses the importance of understanding one's own sleep patterns and how to identify variables that can help improve sleep, attention, and wakefulness.

Identifying Sleep Patterns

It is important to take note of one's own patterns of waking, light viewing, eating, and exercise in order to identify potential problem areas.

Eating late in the day or using cold exposure late in the day can be detrimental to sleep.

Taking a hot shower or sitting in a hot tub or sauna late at night can lead to a compensatory decrease in body temperature and improved sleep, provided one hydrates well enough.

Exercising immediately after using a sauna can prevent a temperature drop.

Experimenting with Variables

Manipulating one or two variables at a time is best when experimenting with sleep patterns.

Identifying the most powerful variables for one's own physiology is key.

Episode four of the podcast will discuss shift work, jet lag, and age-dependent changes in sleeping and wakefulness.

Supporting the Podcast

Overview: This section discusses ways to support the podcast, such as recommending it to others and supporting sponsors.

Recommendation

Recommend the podcast to people who would benefit from the information.

Sponsors

Check out the sponsor links described at the beginning of the episode.

Next Episode

Overview: This section discusses the upcoming episode and when it will be released.

Release Date

Another podcast episode will be released next Monday about the topics discussed this month.

Thank You

Overview: This section expresses gratitude for the audience's interest in science.

Gratitude

Thank you for your interest in science.