Work in 90-minute bouts: using ultradian cycles for focus
September 29, 2026 · 25 min read
Huberman's focus toolkit, time-perception episode and learning episode all recommend focused work blocks of up to 90 minutes, with a warm-up and a decompression period. Matching work to natural cycles gets more done with less strain.
The rules, numbers and steps worth keeping in front of you.
- Work in focused sessions of 90 minutes or less.
- Reason given: waking life, like sleep, runs in roughly 90-minute cycles.
- After about 90 minutes, the chemicals supporting focus run low.
- You choose when a session starts; set a timer.
- The first five to ten minutes are warm-up and count toward the session.
- Focus will flicker; returning to it is the training.
- Stopping at 45 minutes is fine if you are spent.
- Afterward, rest 10 to 30 minutes on easy tasks with no phone.
- Space deep sessions two to four hours apart; never back to back.
- Start with one session a day for about four weeks.
- Most people can handle two a day; three is the upper limit.
- For learning: spend 7 to 30 minutes making errors at the edge of your ability.
- Schedule sessions at your sharpest time, usually mid-morning; sleep locks in gains.
- Ask a doctor before using stimulants, supplements, cold exposure or medication for focus.
This is the short form. The full insight has every expert's reasoning, their own words and the sources.