Sleep

Overview

Sleep, particularly diring the deep slow-wave phase, is when the body repairs its tissues. Behind almost every sleep problem is a block in energy metabolism, specifically low thyroid function. When thyroid, blood sugar, and metabolic rate are optimal, the body gets into the deep restorative phase quickly and can be fully restored in seven or eight hours. When these things aren't optimal, someone can sleep for ten or eleven hours and still wake up fatigued and stiff. The night is a stressful time: blood sugar falls, the stress hormones rise, and most of the body's daily breakdown and aging happens in the dark hours. Keeping blood sugar steady through the night with the right foods, by supporting thyroid function, and getting enough daylight are the core of good sleep, as the entire point of sleep is to restore the glycogen and energy needed to resist stress the next day.

Key Points

• Behind almost every sleep problem is low thyroid function. The immediate trigger is often depleted glycogen stores and intestinal irritation that keeps adrenaline up during the night, but the underlying issue is energy metabolism. The liver needs thyroid working chemically in its local cells to activate the enzymes that convert glucose into glycogen. In good health the body stores more than half a pound of glucose as glycogen, enough to keep the system running for eight to twelve hours, but if thyroid function is blocked, there is not enough stored glycogen to get through the night.

• Deep slow-wave sleep is what repairs tissue, and hypothyroid people cannot reach it. Early sleep studies that monitored brainwaves found that hypothyroid people never got below the second level of sleep and never reached deep restorative sleep. That is why a low-thyroid person might spend eight to eleven hours in bed semi-sleeping and still wake up unrested, often with pain that is worse in the morning than it was at bedtime. When you are supplied with thyroid, vitamin D, and calcium, the sleep gets into the deep slow phase and repairs tissues quickly, so seven or eight hours restores you fully.

• It takes energy to relax the brain into sleep, the same way it takes energy to relax a muscle. ATP has to be regenerated to relax a muscle, and the brain works the same way: in the absence of thyroid, the brain simply cannot get enough energy to relax and go to sleep. An old way of diagnosing hypothyroidism was the Achilles tendon reflex, where the relaxation phase is slow and notchy in a hypothyroid person, like a pneumatic door closure rather than a loose piece of meat bouncing freely. The brain relaxes slowly in the same way, which is why hypothyroid people often have difficulty both getting to sleep and staying in deep sleep.

• Keeping blood sugar up during the night is the central practical lever for sleep quality. Blood sugar has to stay fairly steady, otherise deep sleep is diminished. When glycogen runs out, adrenaline rises to squeeze remaining glucose from the tissues, and when that fails, cortisol rises, which is why everyone has a peak of cortisol around dawn. Having carbohydrate close to bedtime protects sleep quality. People with cirrhosis of the liver do much better on all their tests when they have a fairly big dose of carbohydrate, sugar or rice at bedtime.

• Sleep exists to restore glycogen in the brain and other tissues. The brain synthesizes and stores glycogen similar to the muscle and liver. With aging or stress this glycogen is depleted. The glycogen is essential even when there is circulating glucose, because it is used for stress-adaptive processes. One of the main purposes of sleep is to get the glycogen back into the brain cells, heart cells, and other tissues so you can expend it resisting stress during the daytime.

• Most aging and degeneration happens during the night, driven by darkness and falling blood sugar. When the lights go out, adrenaline starts rising within about fifteen minutes, whether or not the person has fallen asleep, and darkness itself is the major cause of the high cortisol seen in the morning. During the night, free fatty acids rise steadily along with cortisol, serotonin, estrogen, angiotensin, and parathyroid hormone, all of the things that take tissues apart. The bone loss of aging shows this clearly: most of the day's calcium loss appears in the morning urine, showing that the breakdown happened overnight.

• Daylight stabilizes blood sugar and protects nighttime sleep, while darkness is itself a stressor. Getting bright light all day helps stabilize blood sugar and helps the body store glycogen, while just fifteen minutes of darkness is enough to lower the efficiency of mitochondrial respiration. Keeping bright lights on right up until bedtime minimizes the fall of blood sugar. Vitamin D, which accumulates over the summer, is part of this: people tend to sleep better at the end of summer than in late winter. March can often be a bad time because of cumulative long nights and the year's lowest vitamin D.

• Serotonin and histamine are brain-excitatory inflammatory signals, and insomnia is in effect an inflamed brain. Antihistamine and antiserotonin drugs improve sleep, but you can get the same effect with good nutrition: calcium, vitamin D, and thyroid. Insomnia usually involves both adrenaline and histamine, with adrenaline trying to turn off the histamine while also being excitatory itself, so getting energy production up turns off both and lets the brain relax. Estrogen turns on serotonin, histamine, and the other stress hormones, which is part of why controlling estrogen helps sleep.

• Serotonin produces shallow, non-restorative sleep, not deep sleep. Serotonin is an anti-sleep molecule dressed up as a sleep aid. It is the most potent activator of cortisol release, and tryptophan or serotonergic drugs push you into a torpor-like state that resembles hibernation rather than recovery. Excess serotonin also blocks the very enzyme that converts serotonin into melatonin, so loading up on its precursors interferes with the sleep it is supposed to support.

• Progesterone is a potent GABA agonist and a natural sleep aid. Progesterone converts to allopregnanolone, the same calming metabolite that the FDA approved as a rapidly acting treatment for postpartum depression. Around 30 milligrams taken about an hour before bed, dissolved in vitamin E for absorption, gives many people a noticeably calmer and deeper night. Casein, from a bit of cottage cheese or a casein protein before bed, has a related anti-cortisol effect by inhibiting CRH release.

• Restless leg syndrome is an endotoxin and inflammation problem. The nighttime twitching and crawling sensations track with resistant starch feeding colonic bacteria, driving endotoxin into the bloodstream, activating the TLR4 receptor, and pushing up nighttime cortisol. The condition is blocked by TLR4 antagonists or by the dopamine agonist pramipexole. The dietary lever is to avoid resistant starches, especially in the evening.

• Light at night raises serotonin and shuts down melatonin and dopamine. Blue light after sundown accelerates the enzyme that makes serotonin while blocking tyrosine hydroxylase, the enzyme that makes dopamine, and suppressing melatonin synthesis. The combined effect is the opposite of what you want before bed. Dimming lights, cutting blue light, and reducing electrical and wireless exposure in the bedroom all push the balance back toward sleep.

Notable Quotes

"It's almost always a problem of energy metabolism, specifically low thyroid function."

[Ray Peat — Q&A: How To Sleep Better, Sleep Solutions and Supplements]

"Some of the early sleep studies where they monitored brainwaves and could define the different levels of sleep found that hypothyroid people never got below the second level of sleep, never reached deep reparative sleep."

[Ray Peat — Thyroid, Hypothyroidism and Diet, Lifestyle, Exercise To Fix It]

"I've known very young and very old people both with sleep problems who as soon as they tried a very salty snack at bedtime had perfect sleep. Salt is very effective at lowering adrenaline."

[Ray Peat — Q&A 2]

"It takes energy to relax the muscle. ATP has to be regenerated, it takes regeneration of ATP to relax the brain and in the absence of thyroid the brain simply can't get enough energy to relax and go to sleep."

[Ray Peat — Thyroid, Hypothyroidism and Diet, Lifestyle, Exercise To Fix It]

"Your body cannot afford to sleep if it feels that it lacks the nutrients, the carbon dioxide, the thyroid hormone or the nutrition to synthesize melatonin or GABA or dopamine or any of the other mediators of deep restorative sleep."

[Georgi Dinkov, Generative Energy Podcast with Danny Roddy]

Important Things To Consider

Carbohydrate and salt at bedtime are the first-line remedies for waking in the night. A glass of orange juice or milk with honey can deliver enough sugar to put you to sleep for an hour and a half or two hours, and keeping a second glass ready for when you wake is useful because it takes time for the liver to start storing glycogen. A salty snack such as salty broth, crackers, or pork rinds steadies blood sugar and is very effective at lowering adrenaline. Having fat along with the carbohydrate slows absorption and can help you sleep through the night.

People who wake at 2 or 3 a.m. and cannot get back to sleep are out of stored sugar. Fructose and fruit sugars during the day help replenish liver glycogen so the stores last through the night. People who wake repeatedly can use an alarm to wake themselves before the stress surge hits, take orange juice or milk, and over three or four nights lengthen the time between wakings until the liver is stocked enough to fully sleep throug the night.

Coffee timing depends on liver function. If the liver is very hypothyroid and slow to metabolize things, you may have to avoid coffee in the early afternoon because the caffeine keeps circulating. But when the liver can store glycogen, coffee right up to bedtime can improve the depth of sleep, because caffeine acts as an aromatase inhibitor and lowering estrogen reduces the serotonin and histamine that disrupt sleep.

Night-shift work is very bad for health and raises cancer incidence. Darkness is several times more destructive when you are awake than when you are asleep: blood tested every fifteen minutes shows that all the stress hormones rise more quickly during darkness if you are not sleeping. Avoiding night work when possible is important.

Sleep apnea is treatable through progesterone, caffeine, and thyroid rather than only with a machine. The standard belief that carbon dioxide rises too high is backwards: detailed measurements show these people are hyperventilating and blowing off so much carbon dioxide that there is not enough to stimulate the breathing reflex. Progesterone, discovered over fifty years ago to regulate breathing in newborns, works immediately so that one bedtime dose can restore breathing through the night, but the underlying deficiency is thyroid and vitamin D.

Melatonin carries endocrine risks and is not a benign sleep aid. Its function seems to be detoxifying serotonin, and in a short-term emergency it may help, but in animal studies it was capable of lowering both progesterone and thyroid while increasing estrogen. Physiological melatonin sits in the microgram range, yet supplements are commonly sold at three, five, or even fifteen milligrams. At those doses, negative feedback shuts down the enzyme that makes melatonin from serotonin, serotonin backs up, and the result is vivid nightmares that resemble the dreams seen in PTSD.

Both too little and too much sleep are linked to worse health. The statistics suggest seven to eight and a half hours per night is associated with the longest lifespan and lowest symptoms, while short sleepers and very long sleepers tend to have more health problems. If extra sleep leaves you groggy with low blood sugar and a headache, there is a deeper metabolic issue.

Nightmares and night terrors sit on the same continuum as more serious events. Estrogen activates histamine, serotonin, and cortisol, and very low blood sugar combined with high estrogen, serotonin, and cortisol produces nightmares, night terrors, and in severe form is closely related to nocturnal epileptic seizures. Insomnia is the first stage of these more serious things. Disturbing or hard-to-digest foods, spicy meals, or gas pressure during the night can trigger nightmares in someone who otherwise would not have them.

Red light is protective. Pre-bedtime red light exposure was found in a Chinese study to improve both the depth of sleep and the next day's athletic performance.