The Foundational Role and Societal Struggle with Sleep
Sleep is not a passive state but an incredibly active state for both the brain and the body. It is so foundational that there seems to be no major physiological system or operation of the mind that is not wonderfully enhanced by sufficient sleep or demonstrably impaired without it. Insufficient sleep can change the very DNA nucleic alphabet that spells out a person's daily health narrative. Short sleep predicts all-cause mortality, meaning the shorter the sleep, the shorter the life. A lack of sleep also distorts the activity of 711 genes, with some linked to cardiovascular disease or inflammation being overexpressed, and others related to the immune system being impaired. Society struggles with sleep due to a lack of education, as medical doctors in training often receive only about 1.2 hours of sleep education across 11 different curricula. Furthermore, there is a stigma where individuals are proud to discuss healthy eating or exercise, but avoid discussing consistent 8.5 hours of sleep, fearing they may be perceived as not busy or unimportant.
The Four Macros of Good Sleep
Good sleep relies on four main components, referred to as the four "macros": Quantity, Quality, Regularity, and Timing. These components act like the four legs of a chair; if any one becomes unstable, the chair will topple over.
- Quantity: The ideal range is 7 to 9 hours; the minimum required to survive, 7 hours, is distinct from the amount needed to thrive. The number of individuals who can survive on six hours of sleep or less and show no impairment is zero.
- Regularity: This is the single most impactful thing a person can do to improve sleep. Highly regular individuals, going to bed and waking up within a plus or minus 15-minute window, had a 49% relative decrease in all-cause mortality, a 39% cancer mortality risk reduction, and a 57% cardio-metabolic disease risk reduction compared to the least regular sleepers. In a statistical comparison, regularity beat out quantity in predicting all-cause mortality. Regularity works by anchoring the suprachiasmatic nucleus, the master 24-hour clock in the brain, which thrives on consistent signals of waking and sleeping times.
- Quality: Defined by sleep continuity and the power of deep non-REM slow brain waves. Sleep continuity is measured by sleep efficiency, the percentage of time in bed spent asleep, which should be 85% or above. Quality, as much as quantity, predicts all-cause mortality, and shows an even bigger signal when related to mental health.
Sleep Banking and Debt Repayment
The concept of sleep as a bank has evolved with new data. Regarding cardiovascular disease risk, short sleeping during the week, followed by long catch-up sleeping on the weekend, was associated with a 20% reduced risk compared to those who short-slept all week. However, the immune system, blood sugar regulation, and cognitive ability do not rebound from sleep debt paid off on the weekend. A newer concept is sleep banking, where individuals extend their sleep in the days or week before an anticipated period of sleep deprivation. This builds a buffer that allows individuals to suffer about 40% less impairment in cognitive performance when facing subsequent sleep deprivation compared to those who did not bank sleep.
Recommended Sleep Interventions and Hygiene
The three most impactful interventions are digital detox, regularity, and light control.
- Digital Detox: Try to limit activating social media, email, and text messages for one hour before bed. The primary problem is not blue light, but that these devices are highly activating "attention capture devices" designed to mute sleepiness.
- Light Control: The modern world is "dark deprived". One hour before bed, nearly all lights should be turned off or dimmed to reduce light intensity. Dropping the lighting to below 30 lux and using warm yellow light 90 minutes before bed has been shown to increase REM sleep by 18%. The ideal room temperature for sleep is around 18°C.
- Breaking Conditioned Arousal: The 20-minute rule should be followed if one cannot fall asleep. If in bed for about 20 minutes without sleeping, one should get out of bed and go to a different room in dim light, e.g. read a book or listen to a podcast, and only return when sleepy. This breaks the learned association that the bed is a place where one is wide awake.
- Middle-of-the-Night Awakenings: Do not look at the clock, as this increases anxiety and reinforces the waking time. Instead, practice techniques such as guided meditation, breathing exercises, body scans, or vividly taking a mental walk. Counting sheep is counterproductive and may make sleep worse.
Magnesium and Melatonin Supplementation
Relying on supplements is generally seen as "stepping over dollars to pick up pennies" compared to fixing fundamental sleep issues.
- Magnesium: Most common forms, such as magnesium oxide or citrate, do not cross the blood-brain barrier, making them ineffective for brain-produced sleep. Magnesium L-threonate and glycinate have some supporting evidence. Supplementation is only effective if a person is deficient, otherwise, it likely produces "expensive urine".
- Melatonin: This is a hormone that acts as the signal of darkness, telling the brain and body when it is nighttime; it does not generate sleep itself. Clinical data suggests it only improves the speed of falling asleep by about 3.4 minutes and efficiency by 2.2%. High doses, 10 or 20 mg, are supra-physiological and risk causing a morning fog because the body is tricked into thinking it is still pitch black. Recommended doses range from 0.1 to 3 mg. Melatonin is advised for jet lag, when timing is critical, and for circadian rhythm disorders. There is an exponential increase in melatonin use in pediatric populations, correlated with a 53% increase in poisonous overdose hospital admissions over ten years in the US.
- Other Supplements: Supplements like ashwagandha and phosphatidylserine may help alleviate the "tired but wired" phenomenon, where stress prevents sleep, by reducing cortisol and ratcheting down the fight-or-flight nervous system.
The Functions of REM Sleep and Nightmare Treatment
REM sleep (Rapid Eye Movement or dream sleep) accounts for the majority of sleep in the second half of the night, especially the final two hours.
- Emotional First Aid: Dreaming acts as "overnight therapy," stripping the emotional charge from difficult memories. It is the only time during the 24-hour period when the stress neurochemical noradrenaline is completely shut off, allowing the emotional centers of the brain to reprocess experiences in a safe environment.
- PTSD and Nightmares: The failure of this process, often due to persistently high levels of noradrenaline, is believed to explain the repetitive nightmares seen in PTSD. Nightmares serve as a sensitive biomarker for suicidal tendencies, predicting an 800% higher likelihood compared to disrupted sleep.
- Image Rehearsal Therapy is the most powerful treatment for nightmares, utilizing the process of memory reconsolidation. The patient actively recalls the nightmare and then works with a therapist to rewrite the narrative and outcome, and this modified memory is then reconsolidated during subsequent sleep.
- Creativity: Dreaming is a form of "informational alchemy" where new information is fused with an entire back catalog of associations, leading to creative breakthroughs and solutions for previously impenetrable problems.
New Medications and Genetic Short Sleepers
A new class of FDA-approved sleep medication, called DORAs (Dual Orexin Receptor Antagonists: e.g., Suvorexant, Lemborexant, Daridorexant), represents the latest advances in sleep pharmacology.
- Unlike older sedatives like Ambien, DORAs do not sedate the cortex but instead dial down the volume of the wake-promoting brain chemical orexin.
- DORA-induced sleep is beneficial because it enhances the brain's natural cleansing system, the glymphatic system, washing away metabolic toxins linked to Alzheimer's disease, such as beta-amyloid and tau protein. Conversely, Ambien has been shown to decrease this cleansing fluid.
The existence of genetic short sleepers, those with the DEC2 or ADRB1 genes, proves that evolution figured out a way to compress sleep, allowing individuals to thrive on as little as 6.25 hours of highly efficient, dense sleep with zero impairment. The probability of having these genes is extremely low, less likely than being struck by lightning. The dystopian concern is the potential future use of genetic editing tools, like CRISPR, to reduce the population's need for sleep, which would likely lead to people taking advantage of the new minimum and causing further sleep debt inflation.
The Interplay of Sleep, Diet, and Hormones
How a person sleeps dramatically changes how they eat and how they dispose of calories.
- Appetite Hormones: When underslept, the appetite hormone leptin, that signals fullness, is impaired and drops, while ghrelin, that signals hunger, increases, resulting in a 30–40% increased hunger drive.
- Weight Loss: Sleep deprivation causes the body to favor disposing of calories as fat. When dieting while sleep deprived, 70% of the weight lost comes from lean muscle mass rather than fat.
- Fasting and Ketosis: When the body is in a calorically deprived or fasted state, the brain releases the wake-promoting chemical orexin, an evolutionary response to force the individual to stay awake longer to find food. This often results in shortened, less restorative sleep during the initial transition period of fasting.