Sleep and recovery
Sleep is not a pause but the moment body and brain recover: in deep sleep, in clearing waste products, in consolidating what you learned during the day. How well that works depends on rhythm, warmth, light and rest — and only then on the bed. This guide brings together what we know about it, with sources, and what you can do yourself.
Feel it, don't measure it.
In a short time, sleep has gone from a necessity to a project: rings, scores, supplements. Some of it helps. Some of it makes things worse — go to sleep to hit a number, and you sleep worse.
This guide takes a different way in. First understand how sleep works, then set the conditions right, and leave the verdict to the only instrument that really matters: how you feel in the morning. Every claim about the body has a source; where we don't know something, we say so.
How it works
The biology behind a good night, in plain language.
Your circadian rhythm is an internal clock of roughly twenty-four hours that determines when you are sleepy or alert. It drives your melatonin, cortisol and body temperature, and it is reset every day by light — above all by bright morning light. A stable rhythm is the basis of good sleep; without that rhythm no bed does what it could do.
Every night you go through four to six sleep cycles of roughly ninety minutes. Each cycle contains light sleep, deep non-REM sleep and REM sleep. Deep sleep repairs the body and cleans the brain; REM sleep processes emotion and anchors memory. You need both, and in the right proportion.
Adenosine is a substance that accumulates in the brain during your waking hours and so builds sleep pressure — your natural, growing desire to sleep. During sleep, adenosine is broken down again, so that you wake up fresh. Caffeine blocks the receptors and postpones that pressure, but doesn't take it away.
The glymphatic system is the brain's cleaning network: it flushes waste away through the cerebrospinal fluid, including amyloid-beta, the protein linked to Alzheimer's. That happens almost exclusively during deep non-REM sleep, when brain cells shrink and flow increases sharply.
Your chronotype is your genetically determined preference for when you sleep and when you are most alert — from the early lark to the late owl. You cannot fundamentally change it, but you can tune your sleeping times, your work and your exertion to it. Roughly half of it is hereditary.
What you do yourself
Warmth, light, sound and rest: the dials you turn yourself.
A simple countdown to bedtime: ten hours before, no more caffeine; three hours, no heavy meal or alcohol; two hours, no work; one hour, no screens; and zero snoozes in the morning. It tackles the most common disrupters of your sleep one by one.
Your body falls asleep because your core temperature drops, not because you are tired. A sauna or a hot bath, roughly ninety minutes before bed, first drives that temperature up; afterwards it falls further and faster than it would on its own. That is why a sleep spa has a sauna and not a bar.
The ideal bedroom is cool — around eighteen degrees — with humidity between forty and sixty per cent. The coolness helps your core temperature make the 1.2-degree drop needed to fall asleep; the right humidity keeps your airways and skin settled and prevents mould.
The ideal bedroom supports your biology on three fronts: cool, around eighteen degrees, so your core temperature can drop; completely dark, so your melatonin rises undisturbed; and quiet, to prevent micro-awakenings. Clean air and humidity between forty and sixty per cent complete it.
It isn't the volume of a sound that wakes you, but its sudden change. A constant background sound — white, pink or brown noise — reduces that contrast, so that a slamming door or passing car causes fewer micro-awakenings and your sleep cycles stay intact.
Lying awake worrying often arises because your brain keeps holding on to unfinished tasks. Writing down everything on your mind five minutes before sleep — above all a concrete to-do list for tomorrow — gives your brain permission to let go. Research shows this gets you to sleep faster than writing down what you have already done.
NSDR — non-sleep deep rest — and Yoga Nidra are guided protocols that bring you into a deeply relaxed, half-waking state. They restore focus, lower stress and make falling asleep easier, without your actually having to fall asleep. Ten to twenty minutes is enough.
The right bed and pillow keep your spine in a neutral line, and what that takes differs per sleeping position. Side sleepers need pressure relief at shoulder and hip, plus a higher pillow; back sleepers more support in the lower back and a lower pillow; front sleepers a firm base and a very thin pillow or none at all.
In your situation
What changes when your life makes other demands on sleep — and when you'd better stop measuring.
Sleep is the part of training nobody sees. With too little sleep, reaction time, accuracy, endurance and mood suffer most. In a well-known Stanford study, basketball players ran faster and shot more accurately after weeks of sleeping longer. If you train seriously, fixed bedtimes and a cool, dark room often gain you more than an extra session.
After fifty, sleep changes in a predictable way: you sleep more lightly, wake more often and deep sleep decreases. Research suggests older adults don't need less sleep, but find it harder to generate. That makes the conditions more important: fixed times, daylight during the day, a cool and quiet room, and a bed on which pressure points and turning don't wake you.
Jet lag arises because your internal clock lags behind local time, and that clock shifts only slowly. The most important lever is light at the right moment: in the morning after travelling east, in the evening after travelling west. Going east is harder than going west. Melatonin can help; discuss its use and dose with your doctor or pharmacist.
A sleep tracker is reasonably good at telling whether you are asleep, but much less good at telling which sleep stage you are in — and those stages are what the app shows biggest. People who let the numbers steer them can end up sleeping worse; sleep researchers call this orthosomnia. The most reliable measure remains how you feel in the morning, several weeks in a row.
A bed doesn't cure back pain. What it can do is stop causing or sustaining it — and for some people that makes a considerable difference. The question isn't whether a bed is expensive enough, but whether your spine lies straight in it and whether you can change position without waking. If you have genuine complaints, see a doctor or physiotherapist first.
Anyone can compare two beds on paper. We are going to compare them on nights: every guest sleeps a full night on one model, and with permission we record how that night went and which model was ultimately chosen. At this moment we have measured zero nights, because we haven't opened. This page exists so that you can already see what we are going to measure, and how.
Regularity. Fixed times keep your internal clock steady, and everything else builds on that: deep sleep, falling asleep, waking up. Then come daylight, a cool and dark room, and warmth an hour and a half before sleep.
Not necessarily. Trackers are reasonable at how long you sleep and mediocre at sleep stages, and some people sleep worse because of them. How you feel during the day, over a few weeks, is the most reliable measure.
Less than the conditions, but not nothing. A bed that sleeps warm, creates pressure points or wakes you when you turn costs sleep — and as sleep gets lighter, for instance with age, that counts for more.
Sauna, pool, a light meal, and then a Hästens in a quiet, dark room. That is SleepSpa: everything in this guide in one evening.