2 guides · category
Sleep basics
How sleep actually works — cycles, stages, breathing science, what different age brackets need.
Sleep cycles explained (90-minute rule)
REM vs deep vs light — what actually happens in each stage and how the 90-minute cycle drives our sleep-cycle calculator.
7 min read·Updated 2026-05-01
Breathing exercises for sleep
4-7-8, box breathing, and physiological sigh — which one actually works and when to reach for each.
6 min read·Updated 2026-05-01