Plainly written health guides, with the evidence graded
7 guides
Edited by Bram Ferreiro, contributor, sleep and stress.
The mechanism connecting light to melatonin is one of the best-established findings in sleep biology. Whether an ordinary evening of phone use delivers enough of it to be the reason you're still awake is a narrower, murkier question.
Limited evidence18 Sept 2026
The summary screen reports a stage-by-stage breakdown with the confidence of a lab printout. The sensor producing it has never recorded a brainwave, which changes what the number is actually worth.
Limited evidence18 Sept 2026
Chronobiology says light timing can shift your body clock to match a graveyard schedule. Most permanent night workers never fully get there, and the reason has little to do with discipline.
Moderate evidence18 Sept 2026
The common advice — stop caffeine by early afternoon — is built on one average adult's clearance rate. Whether that fits your own bedtime depends on a number that varies enormously between people.
Moderate evidence18 Sept 2026
The line everyone repeats is 'eight hours.' The number actually published is a range that shifts by decade of life, and the harder question isn't which target to hit — it's what a night below it really costs you.
Strong evidence18 Sept 2026
Both stages get called 'the important one' by different corners of the internet, as if a night had to pick a winner. What each stage actually is — and which one's absence is the real red flag — is a sharper question than ranking them.
Strong evidence18 Sept 2026
The wake-up gets blamed on a hormone spike, a digestive clock, or a sleep stage gone wrong — explanations more specific than anything a major health authority actually publishes about insomnia.
Moderate evidence18 Sept 2026