How to Get the Most From Your Sleep Cycles – Dr. Dan Pardi on Health Theory

Check out the Impact Theory Episode Page & Show Notes

Key Takeaways

  • More information is not the answer to behavior change
  • If you want to be good at decision making, you have to get adequate sleep
  • Tips to improve your sleep:
    • Spend enough time in bed so that you wake naturally without an alarm clock
    • Go to bed and wake up at the same time every day
    • Avoid blue light within 2 hours of going to bed
    • Try to get as much natural daylight during the day as you can, especially in the morning
  • Fat cells actually have photoreceptors (aka light receptors)
    • It’s been found that fat cells shrink and become less inflammatory when exposed to light, and release a whole different profile of hormones
  • Heat and cold stress increase the production of heat/cold shock proteins in the brain which have a whole host of benefits

Books Mentioned


Behavior Change 101

  • Tom has read the book Change or Die
    • “The concept is straight forward – you tell people to change and most people don’t”
  • Dan comments:
    • In order for someone to adopt and sustain a healthy behavior for the long-term (not just a 30 day period), they should know:
      • Why they’re doing something
      • How to do it
      • If they’re doing it
      • If it’s working
    • More information is not the answer to behavior change

The Steps for Behavior Change

  • Understand the problem at hand
    • “If you don’t really know what your challenge is, your own efforts will be either inefficient or you won’t know if you’re headed in the right direction”
  • Be a lifetime learner
    • An example to show the importance of learning:
      • 15 years ago circadian rhythms and microbiome science were not part of any model to depict health – now we realize they’re EVERYTHING
    • Information is always changing
      • Dan recommends to – “Have strong opinions held loosely”
  • Be able to take big concepts and personalize them into your life
    • Take ideas and make them real for YOU
  • Address failure with compassion and resilience
    • Failure will be a part of the process – you need to be able to deal with it

How does Dan define health?

  • “It is the ability to maintain balance or homeostasis within the body”

How important is sleep?

  • “If you want to be good at decision making, you have to sleep” – Tom
  • The 3 most important things sleep does for us:
    • It purges neurotoxic and energetic byproducts
    • It helps to regulate our immune system
    • It increases brain plasticity

Sleep Tips

  • “Spend enough time in bed so that you wake naturally” 
    • Don’t use an alarm when possible 
  • Dan’s advice – aim to spend a half hour more in bed than you think you’ll need
    • This is crucial – You’re not sleeping for 8 hours if you spend only 8 hours in bed, you likely wake up a few times during the night, and then add to that the time it takes you to fall asleep
  • Regularity is key – Go to bed and wake up at the same time every day
    • If you don’t, you’re missing out on key sleep stages (Dr. Matthew Walker talked more about this in these Podcast Notes)
  • Avoid blue light within 2 hours of going to bed
    • If you have to use a computer or your phone, wear blue light blocking glasses (use the code “PodcastNotes10” for 10% off at checkout) 
  • Experiencing a wider range of temperatures during the day might help you sleep better at night
    • “We live in a very insulated world”
    • The temperature range humans are exposed to is very narrow
      • If it’s cold, we bundle up
      • If it’s hot, we just stay in the AC
  • Try to get as much natural daylight during the day as you can, especially in the morning
    • “We spend 90% of our time indoors now”
    • Don’t wear sunglasses before late afternoon

A Cool Discovery

  • Fat cells actually have photoreceptors (aka light receptors)
    • These are the same receptors as the ones in the back of our eyes
      • They have the ability to transduce a light signal into a nerve signal
  • Why does this matter?
    • It’s been found that fat cells shrink and become less inflammatory when exposed to light, and release a whole different profile of hormones
      • “You think of weight gain and you think of food, but it’s possible that light may be playing a huge role”
    • “We [society] might not only have a light deficiency in relation to vitamin D, but also for our regulation of fat”

Fat Regulation

  • “We regulate fat tissue like we do temperature”
    • This is similar to how setting a thermostat regulates the temp. within a home
    • When we eat – the calories matter, but our body is running complex processes to “decide” whether fat cells should shrink/expand
      • Our body is always fighting to keep fat levels within a certain range/at a certain set point
  • Why do we gain weight then?
    • Our body is better at defending against weight loss than weight gain
      • This kind of makes sense evolutionarily 

What drives our food intake?

  • Ghrelin is the hunger hormone
    • It’s low after a meal, and as it rises in between meals you get hungrier
  • Leptin is the opposite – but it’s more so operating in the background
    • It sets the tone for how full you’ll be from a meal 
    • If you have low leptin levels, you’ll naturally be less sensitive to the fullness signals from a meal


  • “We live in an environment that’s designed for overconsumption”
    • It’s very easy to overeat due to the palatability of food nowadays
  • Check out the book – The Ultimate Volumetrics Diet
    • “It’s stunning how we condense calories into modern food products” – Tom
    • Think about how many calories something like a small processed cookie has

How is your decision making ability affected if you sleep poorly?

  • It comes down to the “neuro-competitive model of decision making”
    • With a lack of sleep – If you look at something like a cookie, the reward center of your brain will light up first/respond quicker before the executive/self-control area kicks in to stop you from eating it
  • “Reliably, people that miss out on only an hour or two of sleep have impairments in vigilance”
    • When people are sleepy, they’re much more likely to eat foods that are sugary/not at all healthy

What’s going on metabolically when you’re not getting enough sleep?

  • Your blood profile starts to look like that of a diabetic
    • This occurs even after one night of total sleep deprivation or just a few nights of partial sleep restriction
    • Over time then – people that get less sleep are much more likely to develop diabetes
  • Side note – Melatonin (the hormone that tells your body it’s time to sleep) actually causes a bit of insulin resistance – this is good
    • Over the course of the night, you don’t really want insulin taking too much glucose out of the bloodstream and storing it, or else your blood sugar would drop too low and you’d wake up
  • Our fat tissue becomes less sensitive to the effects of insulin 
    • (This means that our fat cells aren’t reading the signal of insulin as well, so more glucose stays in the bloodstream instead of being shuttled into fat cells)


  • It’s been found that you have stronger willpower when you exercise regularly
  • “When you exercise every day you’re toughening your mind” – Tom

The Best Ways to Lose Weight According to Dan

  • Try a ketogenic diet
    • “I’ve seen people lose 100s of pounds with that type of diet
  • But in general…
    • Construct a diet that makes it easier for the body to take in fewer calories comfortably – keto does this well

Heat and Cold Exposure

  • One of the key benefits – they elicit the production of heat/cold shock proteins (chaperone proteins)
    • What do these proteins do?
      • They find misfolded parts of proteins within cells, bind to them, and attempt to reconstruct them back into a normal configuration
      • If those misfolded proteins are “too broken,” heat/cold shock proteins will help to aggregate them and deliver them to the cellular lysosomes for breakdown and clearance as part of the autophagy process
  • Cold and heat stress seems to improve mood, similar to how exercise does
  • Men who use the sauna 4-7x a week, compared to 1x a week, have a ~65% reduction in risk for all forms of dementia and cardiovascular disease
  • Related:
    • Tom and Dan both take a cold shower every morning
      • Tom says it gives him some huge mental benefits

gamma-Hydroxybutyrate (GHB)

  • It’s been most commonly used as a date rape drug…but it has some fascinating effects
    • It actually seems to be protective against Alzheimer’s Disease (more below)
  • You could actually buy it in the ’90s in lots of health food stores
    • People would take it to sleep better
  • Bodybuilders started taking it – the drug was found to stimulate the release of growth hormone
    • How? – It improves a form of slow wave sleep (aka deep sleep) and that’s when most of your growth hormone is released
    • But it was eventually found to release growth hormone on its own, independent of sleep – this led to bodybuilders taking it every couple of hours
      • But this frequency can downregulate the neural systems it’s activating which can result in very serious withdrawal symptoms
  • When the popular date rape drug Rohypnol was banned, GHB became its replacement as it was so widely available
  • Back to GHB and Alzheimer’s Disease…
    • GHB has been found to improve slow wave/deep sleep
    • This is the stage of sleep in which beta-amyloid plaques (and other neurotoxic substances) are cleared from the brain (which contribute to the development of Alzheimer’s disease)

These notes were edited by RoRoPa Editing Services

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