1.10 - Better sleep

Sleep is the practice it's hardest to argue against. Everyone knows they should sleep more and better. Almost nobody actually does, and we tolerate the costs as if they were normal.

The costs aren't normal. Persistent poor sleep is associated with weight gain, heart disease, type 2 diabetes, depression, anxiety, dementia risk, weakened immunity, and shorter lifespan. A single night of poor sleep produces measurable cognitive impairment comparable to being mildly drunk. A week of restricted sleep produces metabolic changes that look like pre-diabetes.

Why sleep matters

A few things sleep does that nothing else can:

Brain detoxification. During deep sleep, your brain's glymphatic system flushes out metabolic waste, including beta-amyloid (the protein associated with Alzheimer's). This cleanup essentially doesn't happen during waking hours.

Memory consolidation. What you learned during the day gets sorted, integrated, and stored during sleep. Skip the sleep and the learning largely doesn't stick.

Hormonal restoration. Growth hormone is released primarily during deep sleep. Cortisol rhythms reset. Insulin sensitivity recalibrates. Reproductive hormones rebalance. The body is doing endocrine maintenance you can't do any other way.

Immune function. Sleep is when the immune system catalogs threats it encountered during the day and prepares to deal with them. People who sleep less than six hours catch colds at three to four times the rate of seven-plus-hour sleepers.

Emotional regulation. REM sleep processes emotional memories. Without enough of it, anxiety and reactivity compound.

If sleep were a drug, it would be the most powerful, broad-spectrum medication ever invented. It's free.

Early to bed, early to rise

The traditional advice is right. Sleep that starts before 10 p.m. produces meaningfully different sleep than sleep that starts at 1 a.m., even when the total hours match.

Why: your sleep architecture changes across the night. The first half of the night is rich in deep, slow-wave sleep. The second half is rich in REM. If you go to bed late, you compress or skip the deep sleep window entirely. Two people sleeping seven hours, one starting at 10 p.m. and one starting at 2 a.m., aren't getting the same sleep.

A reasonable target for most adults: in bed by 10 p.m., asleep by 10:30, up by 5 a.m. or close to it. That's seven to eight hours, with the deep-sleep window protected. The 5 a.m. wake time also gives you a quiet, focused stretch before the rest of the world starts pulling at your attention.

Not everyone is genetically wired this way. True night owls exist, and forcing them into early-bird schedules has real costs. But people who think they're night owls are usually conditioned night owls, kept up by screens, late caffeine, late food, and the habit of squeezing personal time out of the late hours. Reset the inputs and they often find their natural sleep window shifts earlier.

What this has been for me

Before my kids were born, I was waking up at 8:30 or 9. I'd sleep ten or eleven hours and felt fine. After they were born, the nights got disrupted, the total sleep dropped, and I'd wake up whenever the babies woke up, which was usually around 8 or 8:30 in the morning.

That meant something subtle but important: I was no longer in control of my own day. The first thing I did when I woke up was deal with whatever the babies needed. Feedings. Diaper changes. Helping my wife with whatever was urgent. Getting them entertained. By the time the rush settled, it was time to leave for work. There was no time that was mine.

It wasn't sustainable. I wasn't actually rested, and I wasn't operating with anything close to my full capacity.

The shift happened after the eighteen-day fast I described in the fasting chapter. Somewhere in the second week of that fast, my sleep changed. I started waking up naturally at five in the morning, fully alert, and the pattern stuck after the fast ended. That single change reshaped everything else.

Five a.m. gave me two to three hours before the rest of the house woke up. I'd stretch. I'd meditate. I'd go for a walk if I felt like it. I'd handle whatever planning or thinking the day was going to need. Three hours of personal time before the world started asking anything of me. By the time my family was awake, I wasn't reacting to the day; I was meeting it ready.

It's the change I'd point to as the single biggest shift in my daily quality of life since becoming a parent. And it was almost entirely about the time of day I woke up.

What ruins sleep

The list of things that ruin sleep is longer than people realize:

Light, especially blue light, in the evening. Phones, screens, overhead lights tell your body it's still daytime, suppressing melatonin release. Get bright light in the morning, dim everything down after sunset. If you do need to use screens in the evening, turn on the night-mode setting on your phone and computer (Night Shift on Apple devices, Night Light on Windows, similar names on Android). It warms the screen color and reduces blue light output. Blue-light-blocking glasses are another option for late screen use. Neither fully replaces just dimming the lights, but both meaningfully reduce the damage.

Caffeine after lunch. No caffeine after 12 or 1 p.m. is the simple rule, and it applies to more than just coffee. Black tea, green tea, and yerba mate all carry meaningful amounts of caffeine. Chocolate too, especially dark chocolate, which contains both caffeine and theobromine (a related stimulant with an even longer half-life). A 4 p.m. coffee still has 25% of its caffeine in your system at 4 a.m. Even if you fall asleep, the sleep is shallower. An evening square of dark chocolate can cost you a couple of hours of deep sleep that night. If you need an afternoon pick-me-up, a genuinely caffeine-free herbal tea (rooibos, peppermint, chamomile) or a short walk works better than anything that's going to cost you sleep tonight.

- Alcohol within four hours of sleep. It puts you to sleep faster but destroys the second half of the night, especially REM.

Late or heavy meals. A heavy meal within three to four hours of bedtime forces your body to digest when it's supposed to be resting. Sleep gets shallower, body temperature stays higher, deep sleep drops.

A warm bedroom. Body temperature has to drop a degree or two for deep sleep to happen properly. Most bedrooms are several degrees too warm. 17 to 19°C (62 to 67°F) is the standard recommendation.

Noise pollution. Even noises that don't fully wake you fragment sleep architecture. Earplugs, white noise machines, or a quiet bedroom matter more than people realize.

Light pollution. Streetlights leaking through curtains, glowing electronics, alarm clock displays. Eyes can detect light through closed lids, and even small amounts disrupt melatonin. Blackout curtains and an eye mask are low-cost and high-impact.

Stress and unprocessed mental load. A racing mind at midnight is usually a sign that the day didn't have enough quiet processing time. Some kind of evening wind-down (writing, reading, breathwork, meditation) clears the load before bed.

What improves sleep beyond the basics

Two patterns that often surprise people:

Meditation reduces the amount of sleep you need. Long-term meditators consistently report needing less total sleep while feeling more rested. Research backs this up: regular meditation is associated with faster onset of deep sleep, more time in slow-wave sleep relative to total duration, and a generally calmer nervous system that needs less overnight repair work. A mind that has processed some of its load while awake doesn't need as much sleep to do that processing later.

Cleaner, lighter eating reduces sleep needs too. People who shift to whole foods, less processed food, less alcohol, and lighter meals consistently report needing less sleep over time. The logic is simple: heavy or processed food forces the body into more overnight recovery work; clean food does less damage during the day, so the sleep doesn't need to do as much repair. Many people who try a one- or two-week clean-eating reset notice they're waking up earlier, fully rested, without an alarm.

The combined effect is striking. People who meditate regularly and eat cleanly often function on six to seven hours of sleep with the kind of clarity that used to take them nine.

The breathing connection

One thing most sleep advice misses: how you breathe while sleeping matters enormously.

Mouth breathing during sleep dries out the airways, increases the risk of snoring and sleep apnea, raises sympathetic nervous system activation, and degrades sleep quality even when total hours look fine. Nasal breathing produces deeper, more restorative sleep.

Many people don't know they breathe through their mouths at night. Common signs: dry mouth in the morning, sore throat, snoring, waking up tired despite eight hours of sleep.

The simple fix, which sounds odd until you try it, is taping your mouth shut at night. A small piece of medical-grade tape across the lips forces nasal breathing through the night. People who try it for the first time often report the deepest sleep they've had in years within a few days. James Nestor's book Breath is the definitive accessible source on why this matters - it's the book that turned mouth taping from a fringe biohack into a recommendation you can find from physicians.

Don't try it if you have a cold or any blocked nasal passage. Otherwise, a small roll of paper medical tape can be as effective for sleep as just about anything else in this chapter.

Tracking your sleep

If you want to know what's actually working, measure. Modern sleep tracking has become surprisingly accurate, and the feedback loop is the fastest way to identify your specific patterns.

Worth knowing about:

Wearable rings. Oura is the most established; Whoop is the main competitor. They track heart rate, heart rate variability, body temperature, sleep stages, and recovery. They're more comfortable than watches for sleep specifically.

Apple Watch and other smartwatches. Less precise for sleep stages than the rings, but still useful, and many people already have one. The Apple Health app tracks sleep natively.

Phone apps. Sleep Cycle (which can also record snoring) and Pillow are common entry-level options. Less precise than dedicated wearables but accessible.

A caveat: don't get so obsessed with the data that the tracking becomes its own anxiety source. The point is to find a few patterns that change behavior: "I sleep terribly when I drink alcohol after 8 p.m." or "my deep sleep doubles when I keep my room below 18°C." Once you have those, you can largely set the tracker aside.

A pre-sleep ritual

Sleep doesn't start at the moment your head hits the pillow. It starts an hour or two earlier, in the wind-down ritual that tells your nervous system the day is over. Almost any consistent ritual works, as long as it's calming, screen-free, and repeated nightly.

A simple version to start with:

One hour before bed: dim the lights, finish the day's work, stop eating or drinking.

Forty-five minutes before bed: shower (slightly warm, then briefly cool to drop body temperature), brush teeth, prepare for tomorrow.

Thirty minutes before bed: reading (paper book, not screen), light stretching, or breathwork.

Lights out by 10 p.m.

The exact shape matters less than the consistency. The brain is a pattern-recognition machine. Repeat any reasonable wind-down nightly, and within a couple of weeks, the body starts releasing melatonin on cue.

A note on vitamin D. This is the one supplement I take, and I take it only periodically, not year-round. I'm flagging it in the sleep chapter because I've noticed a pattern over years of testing: when my vitamin D drops low, I need more sleep and the sleep itself feels less restorative. Mood and energy take a hit too, but sleep is usually where I feel it earliest.

The science backs the connection. Vitamin D receptors are present in the parts of the brain that regulate sleep cycles, and low vitamin D status is consistently linked to worse sleep quality, shorter sleep duration, and more nighttime waking. For people who are deficient, getting the number back up tends to bring sleep back along with it.

One caveat: if you're sensitive to it, take vitamin D earlier in the day. Taken before bed, it can disrupt sleep.