Sometimes I want to learn a little more about a topic but I don't want to commit to a weekend course, a whole book or a PubMed search. This is typically when I'll turn to podcasts. Podcasts are a great way to dip your toes into a topic before you decide to take the plunge.
I've read my fair share of sleep books but I still learned something from each of the following podcasts. Here are my notes. Hopefully you'll learn something as well.
Chris Kresser’s Revolution Health Radio Podcast with Harpreet Rai
Who is Harpreet Rai? Harpreet is the CEO of OURA Health. OURA Health manufactures the OURA ring that tracks sleep, HRV and physical activity.
There are so many choices for wellness tracking and wearables these days. I'm a bit biased attributing much of my success in overcoming years of on/off insomnia to the information and changes that the OURA ring helped me make. They recently came out with a new version and Chris Kresser interviews their CEO.
How is the OURA ring different from other fitness/health trackers?
The OURA ring is focused on sleep. Clear correlation between health and sleep (chronic disease and longevity) but also in the short term: Sleep is the best performance enhancing drug out there.
Why focus on sleep?
1/3 of population gets less than 6 hours. Over last 30-40 years the amount of sleep we get as a society has dropped by one hour. There is a link between sleep deprivation and several if not all chronic diseases.
Sleep is a form of checking in. The OURA ring is an awareness enhancer. It helps remind us to pay attention to what is needed for behavior change.
The benefit to using technology to track your sleep is:
immediate feedback on changes you may have implemented the day/night before.
How does the OURA ring do this?
In addition to looking at percentage of time spent in the different phases of sleep the ring measures your heart rate variability (HRV)
HRV not just about assessing performance readiness. It is one of the best objective ways to measure stress response.
What is HRV? The inter-beat interval variation of your heart beat and an indicator of how you are dealing with stress. Low HRV is more tied to chronic disease and higher insulin resistance, higher fasting glucose levels. Low HRV is leading indicator for stroke and heart attack. Also an indicator for short term stress.
How does the ring measure HRV?
OURA rings sample heart rate throughout the night. They feel using a ring is the most effective way to do this for a couple reasons. The skin in your hand is extremely thin. The arterial pulse in your finger is 50-100X stronger than your wrist (which is more of a venous pulse)
Sampling occurs with Infrared light shining at 250 Hz: (compared to 10-26 Hz on most other wearables)
Recently published abstract in the medical journal Sleep showed that OURA HRV compared to EKG is 98% correlated
Measuring HRV during the night reflects the accumulation of stresses throughout the day and gives a clearer signal of HRV. There is a cycle: Your night will be the mirror image of your day. So stress management during day is critical for a good night's sleep. Likewise, how you sleep at night sets you up for success on how you'll manage your day.
Benefits to OURA
Gathering metrics for health and wellness is complicated and likely filled with some amount of error. Comfort, ease of use and accuracy are the OURA rings purported strengths.
OURA uses infrared light compared to most other wearable that use green light. Green light is disruptive to your sleep. No LED indicators in the ring (like smart watches have)
For those that are concerned with EMF/wifi the OURA ring has an airplane mode and will store data up to 6 weeks before syncing. The amount of EMF is relatively small as compared to other devices. If you think about energy transfer. The OURA ring has a 15 mA battery and lasts approx a week and an iPhone battery is 50x bigger and lasts day.
Sleep is a systemic issue.
We often have to examine some deep core beliefs about who we are.
Sleep is a behavior and behavior change is difficult. We need to examine core beliefs and not expect changes to occur with just providing education/information.
“Well, if you’re not getting enough sleep, you’re not the best version of yourself the next day.”
Dr. Bubbs Performance Podcast with Chari Mah, MS
Who is Cheri Mah? Cheri Mah is a research fellow at the University of California SF (UCSF) Human Performance Center. She consults elite athletes and professional sports team in the NFL, NBA, MBA and NHL and in her free time is finishing up her 4th year at UCSF to obtain her medical degree.
Why is sleep so fundamental to human health?
1) Sleep has been engrained in our DNA for eons.
2) Sleep has multifaceted effects:
Cognitive (for athlete: impacts reaction time, attention, decision making)
Physiology (impair metabolism, affects hormone regulation: appetite and testosterone)
Immune function affected : more susceptible to illness with inadequate sleep
Physical performance: studies suggest physical decrements with inadequate
She emphasizes its not just about sleep duration ( but quality of sleep and chronological strategies)
Recommendation of average healthy adult: minimum of 7 hours - but individual sleep needs vary
Recommendation for High level athletes: 8-10 hours
How much you think you are getting can be quite different than what you are actually obtaining. ((go read notes from Chris Kresser podcast!)
Focusing on improving your sleep should be done with gradual changes. (add a half hour at a time, shifting bedtime to earlier is easier than shifting wake up to later for most)
Chronic sleep habits most important; athletes often struggle with sleep the night before a big competition.
Some studies show that that sleep banking might help in preventing some of the decrements that come with times of inadequate sleep
Young adults have a delayed body clock where they naturally want to go to bed later. Early morning training sessions may not be the most productive sessions. Schedule periodic recovery days (sleep in am) has shown to benefit recovery in athletes (specifically stress scores)
There is a definitely an impact of travel and time differences on performance and observed circadian misalignment between east and west coast teams.
Rule of thumb is that it takes one day per hour of time zone that you cross to re-acclimate your body clock
Tends to be harder to shift your clock going eastward because our body clock is slightly longer than 24 hours and we always need that exposure to the sun to lock our body clocks into our time zone
Best if you can travel with adequate time before you have to play or perform
NFL study looked at 25 years of night game match ups between east and west coast teams. Regardless of the coast that you are playing on. If you simply bet on the west coast team you'd beat the point spread 68% of the time. Reason why is that body clocks differ. Regardless of the coast where the game was played the west coast team was playing on 3 hour earlier body clock- Late afternoon is time when performance is typically enhanced.
Strategies to deal with jet lag
Most advantageous to prepare in advance.
Pre-flight strategies- Start to shift your body clock a couple days before you fly, go to bed a half hour earlier, sunlight exposure to influence body clock. Get adequate sleep before you travel.
In flight strategies- try not to nap so maintain a sleep drive that will facilitate a transition to new time zone, hydration is key is mitigating the effects of jet lag
Post-flight strategies- Mah is a fan of power naps of approximately 20 min. Timing is important for these too. She recommends in the afternoon because that is when we have a natural dip in our circadian clocks. Its easier to fall asleep. Timing can depend on when you want to have increased performance.
Naps:
Too long of a nap will cause sleep inertia- a grogginess because you woke during deeper stages of sleep. May also decrease your sleep drive and affect your subsequent's night sleep
Naps should be used as an energy boost but not replace adequate sleep
The Caffeine nap (also called a Napaccino): you have to be sleep deprived to fall asleep quickly (within 5-10 min)
Protoccol:
Consume your caffeinated beverage
Fall asleep quickly
Power nap 20 min
Nappaccinos have been shown to be more advantageous than just caffeine alone or just napping alone.
Nutrition: recommends a protein and complex card pre-sleep snack for athletes after games and to decrease fluids an hour before bed.
Nutrition research is starting to show effects on sleep architecture. Timing of meals can benefit sleep and is a significant strategy for mangling circadian clocks
How much sleep do you need? The amount of sleep we need doesn't change as we age but the type of sleep does change. Males in particular start to see a decrease in the percentage of deep sleep
Regarding the application of sleep science, there are 3 buckets to focus on
Sleep Duration
Sleep Quality (stress the wind down routine)
Timing of Sleep
Dr. Moira Junge and Dr. David Cunnington interview Professor Sean Cain
Who is Prof. Sean Cain? A PhD who is on faculty at Harvard Medical School studying circadian rhythms as they correlate to sleep and the impact on cognitive performance.
Circadian rhythm influences more than just sleep and wake times. It influences many things including mood.
The relationship between circadian rhythm and mood may help direct potential treatments for depressive symptoms and maintaining healthy moods.
Patterns observed between those with lower moods and going to bed later.
Sean Cain published on this.
People undergoing treatment with SSRIs for depression who were evening types had more depressive symptoms and more suicidality. They identified a phenotype that did not respond well to these types of anti-depressants
Circadian rhythms are hidden, under the surface and can't be assessed just by looking at sleep/ wake times. They are hard to measure. Hence they can be difficult to manipulate properly.
There are some types of treatments that can harm people with depression more than help them and it’s because of these hidden effects of circadian rhythms
What components of circadian rhythm impact mood?
-the phase/timing of the rhythm (ie, time of day) - esp in relation to sleep -wake behavior.
For example your melatonin onset in the evening is important. If your melatonin onset is 2 hours before your chosen bedtime, that's usually the optimal circadian time to go to sleep.
-amplitude of rhythms (the strength of rhythm) is a reflection of the strength of the signal for your body clock control your sleep-wake cycle but all the other systems that change over the day
Emerging research on circadian rhythms and depression:
Some early research shows that phase delayed individuals are more prone to depression.
Non-optimal sleep that often comes with phase delayed sleep results in disturbed emotional regulation and therefore gives us a more negative bias causing us to perceive negativity more easily.
Phase delay results in a push of your core body trough (your core body temp minimum). This should ideally occur 2-3 hours before you wake. So phase delayed individuals have a really hard time waking up because during the time of your core body temp minimum occurs when body clock has the strongest signal to sleep. This affects your ability to maintain alertness and positive mood all day long.
Anti-depressants and circadian rhythms:
SSRI's greatly increase the responses of the circadian system to light.
It boosts it so much that (even in dim light) melatonin onset was at bedtime. (ie, delayed)
Your body perceives all the light in your home as sunlight, so tricks your clock to thinking that it is still daytime which pushes your melatonin rise later
Anything that tends to increase serotonin will tend to increase light sensitivity
Artificial Light and you:
New LED lights that are more energy efficient are very blue enriched.
The circadian receptors in the eye called melanopsin, are very sensitive to blue light.
The melanopsin is non-visual (compared to rods and cones) so you have no awareness how bright "bright" is for your individual clock. LEDs don't always look blue but they will have often a blue peak measured by a spectrophotometer.
Your melanopsin knows its there and you are responding to it but consciously you don't know its there.
New research being done on light and cognition:
Light, esp blue light, can enhance your expectation of bad things happening.
This might be one of the mechanisms in seasonal affective disorder
Proposed mechanism for why SSRIs work (or don't work) for depression:
In depression your circadian system is less responsive to light so the SSRI counteracts that and normalizes the responsive to light. So this enhances the day mood boosting effect of light.
The downside is the amount of light you get at night. If you have poor rhythms or increased light exposure you end up getting perpetual jet lag. SSRIs are therefore not optimal for evening types.
Most people with depression are hyposensitive to light.
****Important to note the cause for an individuals depression may be multifactorial but this new information brings attention to an important mechanism
This is just one example of how optimal treatment is that which is targeted at the individual. We need to phenotype people better and understand the physiological basis for their depression.
What can you do:
Getting a lot of regular light during the daytime is most beneficial. Mood related to this light exposure is mediated by the circadian photoreceptive system. Regularity of light exposure is more important than anything
Light at night is important: Use warmer lights after dusk
Night shift or fluxx on your phone - note: it is not enough to have these on their default settings. He recommends you ram them up to their max so the screen looks red. Using your phone within 2 hours of bedtime at all will suppress your melatonin and you need that signal to sleep. Phone use shifts your circadian clock
Consistent wake up time and get as much a daylight as you can
Who is Dr. Stash Gominak? An MD specializing in neurology who spent years treating patients with chronic pain and sleep disorders before retiring in 2016 to pursue a career in teaching and coaching medical practitioners about sleep.
Vitamin D role in sleep:
Dr G started seeing that Vitamin D was deficient in most of her patients so contacted Walter Stumpf who had been studying Vitamin D’s role in the brain.
Stumpf and others have found Vitamin D receptors in nuclei that govern sleep. Additionally, there are Vitamin D receptors all over the body : pituitary, ovaries, GI tract, pancreas, fallopian tubes, etc
Vitamin D is the primary endocrine control of any system that had to change with the seasons. (eg. Reproductive, Endocrine)
Vitamin D is actually a hormone.
Historically it was called a vitamin because nocturnal animals that are never in the sun have to get their Vit D source from their food.
Rats got their Vit D from D2 (which is a fungus).
All animals make D3 on the skin in response to sun exposure.
Many animals ingest this Vitamin D3 source by licking and/or preening their fur. Humans and pigs are hairless so we absorb it directly.
The color of skin and amount of melanin we have individually is in part due to the evolution, travel and adaptation of our ancestors. Your skin color may have to do with your sleep. Research shows if you have darker skin you have a higher risk of a sleep disorder.
Vitamin vs. Hormone
In some ways Vit D is like a vitamin because we do take it orally but in many ways it is like a hormone
As soon as you say Vitamin D is a hormone it means there is an ideal blood level.
This has historically made dosing a challenge.
Unfortunately most of the studies being done on Vitamin D are using a fixed dose.
There isn't a recommended dose: There is a recommended blood level.
Vitamin D studies are actually quite novel. It was discovered in the 1930's/40's but in terms of use within population we've really just started.
Many people are lacking in Vit D so how do you address low Vitamin D blood levels?:
It takes time and their blood levels must be monitored while adjustments are made.
The hormone that should be measured that is responsible for our protection is 25(OH)D
If you are really interested the following website might be useful: www.vitamindcouncil.org
Dr. Gominak found many of her patients with pain complained of disturbed sleep and then routine blood work started showing many were low in Vit D.
As she started to treat this she asked: is there a level that would us perfect sleep? She found the answer to this was yes.
There a Vitamin D blood level that gives us good sleep (60-80).
This number is based on a biological mechanism that breaks down the ability to absorb Vit D through various mechanisms but you can't force the blood level above 80 by just using the sunlamp or being out in the sun.
So 80 is the upper level of Vit D due to sun exposure.
Note that ideal blood levels for a number of different conditions differ. (ie, for bone health, for reproductive health, to treat PCOS, for sleep) So ideals depend on what you are targeting
***Once you get Vit D to levels of 60-80 if you need to convert the microbiome back to normal (there is a second piece to this: part 2 of this podcast)
How much Vitamin D do you need for good sleep?
Genetic basis: 2% of people need 500-2000 IU to correct and come back to a good sleep level.
The rest of the population needs 10x that amount: 5000-20,000.
The max we make physiologically is 20,000 but this varies dramatically.
Recommendations for how much sun exposure you get are based on studies done in Boston on white people so accurate recommendations will depend on where you live, your skin color, amount of skin exposure.
Not many studies to guide MDs how to test and intervene with Vitamin D deficiency.
Unfortunately what is happening with most practitioners and patients is they are being put on 1,000-2,000 IU/day and then they are never rechecked.
There will need to be multiple clinical trials to assist doctors for better knowledge. Every single person is unique and that monitoring really needs to be done over 3 years because after you have gotten a patient to the range of 40-50 they still need to be monitored.
Difficult to get funding because this intervention requires no medication and non-pharmalogical intervention has trouble getting funding. Go figure
Vit D levels are supposed to go up and down, in relation to the seasons.
The thing that has led to deficiency and its impact on illness, is not related to Vitamin D itself but the fact that Vit D affects the microbiome.
Our microbiomes are affected by sleep deficiency, sleep apnea as well. If that interests you you should check out part 2 of this podcast.
Who is Matther Walker, PhD? vDr. Walker is a sleep scientist and professor of neuroscience and psychology at the University of California, Berkeley. His research looks at the impact of sleep on health and he is the author of one of my favorite books on sleep called Why We Sleep: Unlocking the Power of Sleep and Dreams.
This podcast was great and if you like what you read you should definitely check out Matthew Walkers book and his podcast with Joe Rogan if you haven't yet.
An emerging clinical disorder called orthosomnia:
Seeing some people who are so fixated on getting their sleep right that they become, anxious and neurotic about it.
Very tiny % of the the population> there is a larger % of the population that underestimates the importance of sleep and doesn't pay enough attention to it
People were more likely to make behavioral changes regarding their sleep if you educate them on the negative health effects versus the positive health benefits.
So here are some negative effects
Sleep loss is serious: If you've been awake for 20 hours straight you are as cognitively impaired as you were legally drunk.
Road traffic accidents are more deathly when caused by sleep than when they are caused by drugs or alcohol. Because accidents related to drugs/alcohol are caused by making a late response vs. falling asleep there is no response (ie braking)
If you're driving a car on only 6 hours of sleep you are 33% more likely to get into a road traffic accident. Nobody would buy a car that was 33% more likely to get in an accident.
It’s a global issue: 50% of adults get 6 hours or less a night in most developed nations.
Sleep loss affects everything: Every major physiological system in your body and every operation of the mind is incredibly dependent wonderfully enhanced when you get and markedly impaired when you don't.
Short sleep predicts all cause mortality
Every disease that is killing us in the developed world is now linked to insufficient sleep: Cancer, Alzheimer, Stroke, CV disease, DM, obesity, depression/anxiety and suicide.
Evidence (over 100K studies)
The number of people that can survive on 5 hours or less of sleep and showing no impairments< rounded to a whole number and expressed as a percent of the population is zero.
DEC2 gene - people with this gene can sleep less than 6 hrs with any impairment. Very very small of population.
Sleep and Timing
Every living organism that lives >24 hours seems to have some type of rhythmic activity to it and that activity is hardwired into our brains and every cell of our body. Each cell has a circadian clock. The suprachiasmatic nucleus (in the brain) is the main clock that rules them all.
Sleep evolved with life on this planet. We have different circadian clocks (chronotypes) because we have evolved that way. Matthew Walker's theory: In the past certain tribe members needed to be awake at night to protect the rest of the tribe so this variability evolved. So chronotypes are genetically hard-wired
What about caffeine?
Sleep pressure is caused by adenosine. It starts to build up in your brain as soon as you wake up. The more build up you get the sleepier you will feel. This usually happens after 16 hours. During the deep sleep your brain usually clears out those levels of adenosine so you wake up refreshed. Caffeine works by latching onto receptors on adenosine and blocks or decreases the sleepiness signal.
The problem is the adenosine continues to build despite caffeine being in your system so by the time caffeine is washed out of the system, you have sleep pressure from before caffeine consumption and the additional sleep pressure that built up while caffeine was in your system. This is called a caffeine crash and you feel like you want to
Caffeine is a psychoactive stimulant.
Caffeine is thermogenic: which increases core body temp, which will increase your alertness. You can you warm non-caffeinated beverages as thermal cues
If you are drinking caffeine before mid-day then you are probably self-medicating your state of sleep deprivation. 10:00 am should be most people's peak level of alertness.
Are you one of those people that say that you can have an afternoon or evening cup of coffee and not have sleep be affected by it? You are wrong.
200 mg of caffeine in the evening; causes a 20% loss of deep sleep (for context this % of deep sleep loss occurs with aging 20-30 years)
Caffeine has a half life of 6-7 hours, has a 1/4 life of 12 hours which means that if you have a cup of coffee at 12:00pm a quarter of that caffeine is still present in your brain at midnight.
Kids and sleep:
Push for later school start times: Delaying school start times results in improved academic grades, behavioral problems decrease, truancy rates decrease, psychological and psychiatric problems and life expectancy of students decrease.
Only 11% of teens are getting the amount of sleep that they need. (When I shared this statistic with my 13 y.o. I got an eye roll. Then a few seconds later a yawn)
Sleep debt: can you make up for sleep loss? Sleep isn't like the bank. You can't accumulate debt and hope to pay it off at a later time.
A recent study that short sleeper during week but long sleepers on the weekends have a reduced risk of death relative to those who were short sleepers during week and weekend but social jet lag has several negative on your health.
How do you know if you are getting sufficient sleep? (subjectively)
you are waking up naturally.
you don't need caffeine to feel awake
no trouble concentrating and focusing
Why do you wake up naturally right before your alarm? 2 possibilities.
you are consistently getting enough sleep and have found your sweet spot.
The other case is called anticipatory anxiety (like when you have to get up earlier than normal but end up doing it naturally). Sleep that night usually lacks deep sleep.
Get your phone out of you room
Removing clock faces from bedroom including cellphones are one of the best pieces of advice.
Even if you aren't checking your phone at night most people do the very first thing in the morning and this anticipation essentially creates a micro dose experience of anticipatory anxiety so sleep isn't as deep.
High anticipatory anxiety correlates to lack of deep sleep.Try and go 5 min in the morning without using your phone. then try and extend this time.
Jet lag.
We are not evolved for this. There is no cure but there some hacks that will help you diminish the severity of jet lag
6 recommendations
For long flights; sleep the first half of the flight but force yourself to stay awake for the second half and the rest of the following day. Need to build up your sleep pressure to ensure you get then are able to fall asleep in new time zone. Shoot for getting 14 hours of consistent, continuous wakefulness
Avoid alcohol and caffeine on flights. Both make it difficult for circadian clock to adjust to new zone.
Once you arrived in new time zone try to get some light exercise (before mid-day)
Try to get 30 min of natural daylight before 10:00 without shades (block the light in the afternoon)
Timed feeding: eat meals at regular times, not just when you are hungry. Food is a powerful trigger to reset your biological clock.
Melatonin: helps time the healthy onset sleep. Can use it strategically in new time zones. Most people take too much. Best dose per MW (.5mg-2mg) and take it 45 min before your desired bedtime
Sleep and learning: Sleep after learning is like pressing save on things you've learned so is the best memory hack. There are lot of different ways to facilitate memory retention including olfactory and visual cues. As you go into deep slow wave sleep
Why do we dream? 2 main functions
Creativity: REM sleep takes the newly made memories in the brain that we form in deep sleep and they interact with all your past memories ("Its like memory pinball or group therapy for memories". New connections and associations are formed. You wake up the ext day with a revised mind web of associative networks that can allow you to solve problems with new insight. This is why the advice to sleep on a problem is good advice. We create novel solutions. We gain knowledge from deep non_REM sleep. We gain wisdom from REM sleep
Emotional First Aid: REM sleep is the only time in 24 hours when the brain shuts off noradrenaline (norepinephrine) a stress hormone. Studies show that when this happens emotional and memory centers of the brain reignite. They are actually 30% more active than when you are awake. Its like overnight therapy.
Level Up your SLEEP!