Sleep science

The useful sleep numbers, where they came from, and how much room they leave for a real person.

I use sleep research to check my spreadsheet, not to pretend every night runs on schedule. This is where I keep the studies and the awkward details, including why a 90 minute cycle may be 70 minutes one night and 110 the next.

Sleep science
The 90 minute sleep cycle is an average, and yours may be 70 or 110
The 90 minute sleep cycle is an average. Yours may run 70 to 110 minutes. Here is where the number comes from and what the sleep calculator assumes.
September 15, 2026, 9 min read
Read more: The 90 minute sleep cycle is an average, and yours may be 70 or 110

Nearby topics

Sleep calculator
Sleep schedule
Naps

The 90 minute sleep cycle is an average, and yours may be 70 or 110

Nearby topics