Notes taken from a Brandon Marcello, Ph.D. seminar:
Not getting enough sleep leads to increased risk of injury and reduced pain threshold; greater susceptibility to sickness; reduced physical and psychological performance; reduced motivation, learning ability, and memory; increased anxiety, irritability, and mistakes; increase in body fat percentage; reverting to old habits; poor justment of distance, speed, and/or time.
Most of the Rapid Eye Movement (REM) cycle occurs in the final 2-3 hours of a night’s rest. Missing ~25% of your total sleep one night may have a larger than 25% negative impact on your mind and body.
Getting enough sleep improves motivation; recovery of muscle strength; sprint speeds; muscle glycogen (stored energy in muscle); cortisol (stress) regulation; motor skill development; memory consolidation.
Sleep debt simplified: if you need 8 hours and get 7 hours, that means you accrue 1 hour of sleep debt. Need to get 9 hours to repay that 1 hour of debt. Sleep debt can build up over time to (30 hours? I failed to write this down).
After extending time in bed to 10 hours per night for several weeks, collegiate swimmers showed improvements of +8% 15meter sprint speed; +20% reaction time off the block; +10% turn time efficiency; +19% kickstrokes.
During sleep, the brain will get rid of waste products and clean out toxic proteins which can impair healthy aging of the brain and cause brain related diseases such as Alzheimer’s and other neurological disorders.
Sleep Myths: you can get too much sleep; naps are bad; 8 hours of sleep is ideal (everyone is biologically wired to require different amounts of sleep); older people don’t need as much sleep (they need more because they usually awaken more frequently); storing up sleep for the week ahead; alcohol helps you sleep.
Sleep/Nutrition Interaction: sleep deprivation alters the ability of the body to metabolize and store carbohydrates for recovery, as well as use for a later time; reduces glycogen levels.
Ask yourself: what is detracting from your sleep quality? Noise? Light? Pain? Temperature? Priorities? Stress? Alcohol/Drugs/Food?
Studies: Predicting Major League Baseball (MLB) Player Career Longevity via Sleepiness Measurements, Validation of a Statistical Model Predicting Possible Fatigue Elementas in Major League Baseball, Chronic lack of sleep is associated with increased sports injuries in adolescent athletes, Sleep patterns of U.S. Military academy cadets (2003), Effect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men
Seminars: One More Reason to Get a Good Night’s Sleep (Jess Iliff), Why Do We Sleep? (Russell Foster)
Books: The Promise of Sleep (William Dement, M.D., Ph.D.), Take a Nap! (Sara Mednick, Ph.D.), The Sleep Revolution (Arianna Huffington)
Info from Joe Rogan Experience interview with Dr. Matthew Walker (Source)
Lack of sleep and physical performance
If you’re getting 6 hours of sleep or less, your time to physical exhaustion drops by up to 30%
Lactic acid builds up quicker the less you sleep
The ability of your lungs to expire CO2 and inhale oxygen decreases
The less sleep you have
The lower your peak muscular strength, lower your vertical jump height, and lower your peak running speed
A higher injury risk
One study showed a 60% increase in probability of injury comparing people who get 9 hours of sleep a night, to those who get 5
Your stability muscles fail earlier when not getting enough sleep
We need 7-9 hours a night
Once you get below 7, we can measure impairments in the brain
There is a small fraction of <1% of the population, that has a certain gene that allows them to survive on 5 hours of sleep
You are more likely to be struck by lighting than have this gene
The gene promotes wakefulness chemistry in the brain
The shorter your sleep on average, the shorter your life
Short sleep predicts all cause mortality
Wakefulness, compared to sleep, is low level brain damage. Sleep offers a repair mechanism for this.
During deep sleep at night, there is a sewage system in the brain that cleanses the brain of all the metabolic toxins that have accumulated throughout the day
One of those toxins is beta amyloid – which is responsible for the underlying mechahism of Alzheimer’s disease
The less you sleep – the more this plaque builds up
Insufficient sleeps is the most significant lifestyle factor for determining whether or not you’ll develop Alzheimer’s Disease
Insufficient sleep is linked to bowl, prostate, and breast cancer
The WHO has decided to classify any form of nighttime shift work as a probable carcinogen
Shift workers have higher rates obesity, diabetes, and cancer
Leptin and ghrelin
Both control appetite and weight
Leptin tells our brain we’re full
Ghrelin does the opposite, it’s the hunger hormone
With less sleep, leptin gets suppressed, and ghrelin gets ramped up
People sleeping 4-5 hours a night will on average eat 200-300 extra calories each day (70,000 extra calories each year which translates into 10-15 lbs. of body mass)
You also eat more of the wrong things
Lack of sleep if a critical factor of the obesity epidemic
1 out of every 2 adults in America are not getting the recommended 8 hours of sleep
1 out of 3 people are trying to survive on 6 hours or less of sleep
The average American adult is sleeping 6 hours and 31 minutes during the week (it used to be 7.9 hours in 1942)
“The number of people who can survive on 6 hours of sleep or less, rounded to a whole number, and expressed as a percentage of the population is 0”
“You don’t know you’re sleep deprived, when you’re sleep deprived”
Under slept employees will take on fewer work challenges, are more likely to slack off in groups, and are less likely to come up with creative solutions
Less sleep does not equal more productivity