79. The Sleep Expert | Get to sleep and stay asleep

Sleep expert Mike Stone, MD joins us for a conversation about how to sleep well (and strategies to do it poorly!).  We cover: how sleep cleans your brain, alcohol, caffeine, a pragmatic approach to wearables, light exposure, the villainy of devices before bed, cannabinoids, heat, room temp, and night shifts.

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Guest Bio: Dr. Mike Stone has been in medical practice for almost 20 years, and currently serves as the Chief Education Officer at Wild Health. Dr. Stone has held academic appointments at Harvard Medical School and UCSF, and has received multiple national awards for education, innovation, and leadership in medicine. He has spent the bulk of his career focusing on educating students, trainees, and colleagues. Mike is obsessed with optimal health and peak performance, with a deep interest in the effects of lifestyle interventions to improve longevity and cognitive function. He is currently focused on knowledge translation for healthcare practitioners, striving to empower practitioners with practical techniques to competently construct strategies and tactics for their patients’ health optimization.

We discuss:

What is sleep and why it is important [04:00];

• A lot happens during sleep:  brain waves slow down, we generate growth hormone, we repair damaged tissues, form new synaptic connections, improve memory, and activate the glymphatic system.
• The glymphatic system is a series of perivascular channels that get flushed with CSF during sleep, ridding the brain of toxins and toxic metabolites that have accumulated over the course of the day.
• Dementia, hypertension, cardiovascular disease, and all-cause mortality all go up in the setting of sleep disturbance and sleep disruption. Even after a single night of sleep deprivation, you can measure significantly increased beta amyloid in the CSF.

“Sleep is a rinse cycle for the brain.”  

The benefits of exposure to morning sun early in the day and limiting light exposure later in the day [08:00];

• You can train your circadian rhythm by light exposure early in the day and then limiting light exposure late in the day. This is critical for getting great sleep.
• Early morning sun can set the circadian cycle.

A primer on sleep stages [09:30];

• You can break sleep stages into non-REM/REM (rapid eye movement) sleep OR into 4 stages: awake, light, deep (aka. slow wave) and REM sleep.
• Deep sleep is important for memory, cognition, and that feeling of restfulness. REM sleep is important for forming new memories, synaptic connections, and in our ability to learn. 
• In an 8 hour sleep session, one normally would complete four to five 90-120 minute cycles of light sleep→ moderately deep sleep → deep sleep→ REM sleep. Earlier in the evening, a bigger portion of the 90-120 minute sleep cycle is deep sleep and later in the evening a bigger portion of the cycle is in REM.

How to use wearable sleep trackers smartly [13:45];

• Wearables are a poor substitute for a high quality sleep study done in a sleep lab, but the trends can be useful for N-of-1 experiments. For example, track the effect of a glass of wine, or cold room temperature, or earlier time to bed on your sleep scores. You will see remarkable changes day to day based on lifestyle interventions.
• Don’t bother with a sleep tracker if a poor score creates stress or negative emotion.

Seeing the impact that your efforts and behavior have on how you sleep can be really great for forming good sleep habits.

Alcohol and sleep [16:40];

• The mechanism by which alcohol disrupts sleep is not totally clear.
• The predominant negative effect is on REM sleep. Deep sleep is fairly well preserved.
• There is a dose-dependent response.  Prospective data shows that 1 drink on average decreases sleep by ~10%, whereas 2+ drinks may decrease it by 36-40%.
• Studies suggest that the negative impact on sleep is alleviated if alcohol is consumed >3 hours before bedtime.
• For many people, one type of alcohol can have a different impact on sleep than another. Many find red wine to have the worst effect.

Light, blue light and screen time before bed [24:00];

• Avoid bright lights between 10 pm and 4 am and only use as much artificial lighting as is necessary to move about safely at night. Blue blockers can help at night but still dim the lights. Candlelight and moonlight are fine.
• If possible, remove phones and devices from bedrooms.

The physiology of caffeine [26:15];

• Caffeine blocks adenosine receptors. Adenosine builds up in our bodies during the day, making us sleepy. It is one of the big signals for when it’s time to go to bed. By blocking adenosine receptors, caffeine leads to alertness. 
• Some people metabolize caffeine more quickly than others and this can be predicted based on CYP1A2, ADORA2A SNPs testing. These results can help people determine the best time to stop drinking caffeine during the day. 
• Caffeine half-life is 4-6 hours on average. Studies suggest that if you have caffeine 6 hours before sleep, the result will be 1 hour less sleep. For slow metabolizers, the effective caffeine half-life may be up to 12 hours and the increase will be even more pronounced for those who are caffeine naive.
• Caffeine has more of an impact on decreasing deep sleep and less of an effect on REM.

The effects of caffeine and alcohol are opposite in the way they affect our sleep architecture, just like they’re opposite in the way they make us feel. 

Cannabinoids as a sleep aid [29:30];

• There is insufficient direct evidence to support CBD, CBN or THC as a sleep enhancer. They may promote sleep indirectly through reducing psychological arousal due to stress, pain, etc.

Heat – what is the ideal room temperature for optimal sleep? [34:00];

• The ideal room temperature range for most people is somewhere between 64 to 68℉. Taking a hot shower to cool your core body temperature before sleeping in a cold room is one hack Mike recommends. He also uses an OOLER Sleep System pad to keep his bed cooled to 56℉. 

Other sleep hygiene ideas [38:20];

• Limit work before sleep. Avoid engaging with email or cognitive work for at least 2 hours and ideally 4 hours before bed.
• Keep computers, phones, and other devices outside of the bedroom.
• When it starts getting dark outside, start darkening the inside. 
• Meditation or yoga nidra before sleep can clear the mind.
• Calming supplements such as magnesium which is inexpensive with minimal adverse effects can be beneficial.

Natural predilection:  the early bird vs. the night owl [40:10];

• Most people wake up around 7:00 AM and go to bed around 9:00-10:00 PM. Some people, however, are biologically wired to sleep in and stay up late.
• There are several chronotype variants which are based on ​​intrinsic preferences about sleep and wake times. If you know your chronotype and can adjust your work schedule/shifts around that, that can be ideal. 

Damage control for night shift associated sleep disturbance [43:45];

• There are significant long-term effects on mental health, cardiovascular disease, dementia, and all-cause mortality from doing night shifts. What’s worse is switching back and forth between night, afternoon, and evening shifts without any regularity.
• You can use light and caffeine timing to trick your body into thinking it’s day or night (when it’s not) to try to minimize the negative effects. Family buy-in is also important.
• Having a schedule that marches forward from morning to evening to night shifts is helpful on the circadian rhythm. Having a couple of days off after a stack of night shifts is critical to recovery.
• Double covering night shifts and keeping them shorter is Mike’s ideal for safely caring for patients and recovery.

Melatonin questions [58:00];

• Mike’s approach to melatonin is that it’s very useful for some people, particularly with a time zone change. Many people also swear by it for night shift resetting. A sleep tracker can help determine the benefits of melatonin on an individual basis.

Shownotes by Melissa Orman, MD

Featured Photo by Kate Stone Matheson on Unsplash