Body clock
Why mornings feel so heavy
That foggy feeling after waking has a name. Here is what makes it worse, and what may ease it.
The journal
All stories
The bedroom
Does stale bedroom air affect your sleep?
Eight hours in a closed room changes the air you breathe. A small study tested whether that matters.
The bedroom
How noise affects sleep, even if you don't wake
You might sleep through traffic. Research suggests your body may not.
The bedroom
What light does to you while you sleep
Your eyes are closed, but a bright room can still change your sleep. Here is what one study found.
The bedroom
How humidity changes your sleep
You notice a hot room right away. Damp or dry air is harder to pin down, but it can change your night.
The bedroom
Why a warm room costs you deep sleep
Heat does more than make you uncomfortable. It trades your deepest sleep for time awake.
Body clock
Circadian rhythms and sleep cycles
How circadian rhythms, sleep stages, and body temperature work together to shape the quality of a night.
The bedroom
Why your bedroom matters more than you think
Sleep quality is not only about the body. The room around you sets the conditions the body has to work within.
Body clock
Why you wake up at 3 a.m.
Waking in the small hours is more normal than it feels. Here is what your body is doing at that point in the night.
Sleep science
What happens to your breathing while you sleep
Your breathing changes all night, and most of it is normal. Here is what is happening, and what is worth raising with a doctor.
Sleep science
Sleep is when your body recovers
How deep sleep drives physical repair, hormone release, immune function, and memory consolidation.