It's sleep quality, not just quantity
Sleep runs in cycles of roughly 90 minutes, moving through light sleep, deep sleep and REM. The restorative work - tissue repair, memory consolidation, hormone regulation - happens mostly in deep sleep and REM. If something is disrupting those stages, even a full eight hours can feel like four.
Common culprits: alcohol in the evening (it helps you fall asleep but fragments deep sleep later in the night), a bedroom that's too warm, screen use right before bed, and going to sleep at wildly different times night to night.
The temperature factor
Your core body temperature needs to drop for deep sleep to kick in properly. A bedroom sitting around 16-19°C tends to work better than a warm room, even if a warm room feels cosier at first. If you run hot at night, breathable bedding matters more than a heavier duvet.
What actually moves the needle
A few changes tend to outperform most sleep gadgets:
- A consistent wake time, even on weekends - this regulates your body clock more than a consistent bedtime does
- No screens for 30-60 minutes before bed, or at minimum a blue-light filter
- Caffeine cut off by early-to-mid afternoon - it has a longer half-life than most people assume
- A wind-down cue your body learns to recognise: dim lights, a warm (not hot) shower, or a few minutes of reading
When to consider a supplement
Magnesium is one of the few supplements with reasonable evidence behind it for sleep quality, particularly for people who are deficient or dealing with muscle tension at night. It won't fix a chaotic sleep schedule, but as one part of a wind-down routine - alongside consistent timing and a cooler room - it can genuinely help you get more out of the hours you're already sleeping.
If tiredness persists despite consistent habits, it's worth ruling out something like a sleep disorder with a doctor rather than assuming it's fixable with routine alone.