For most people, the best time for hard, focused work is mid to late morning, a couple of hours after waking. Alertness then dips in the early afternoon and recovers somewhat in the late afternoon. But that curve slides earlier or later with your chronotype, and matching your hardest work to your own peak gets more out of the same hours.
The daily alertness curve
Your body clock shapes alertness across the day. It's low on waking (while sleep inertia clears), climbs through the morning, dips after lunch (the “post-lunch dip” happens even if you skip lunch), recovers in the late afternoon and early evening, and falls toward bedtime. Body temperature follows a similar curve, and reaction times and many kinds of performance track it.
Your chronotype shifts the curve
Larks, early chronotypes, peak early; owls peak late. Most people are in between. Testing people at their preferred and non-preferred times, researchers have found a “synchrony effect”: Cynthia May, Lynn Hasher and colleagues showed in the 1990s that older adults, who tend to be morning types, did better on memory tasks in the morning, while students, who lean toward evening, did better later in the day.
| Chronotype | Deep work | Second, smaller peak |
|---|---|---|
| Early lark | 7 AM to 11 AM | 2 PM to 4 PM |
| Morning leaning | 8 AM to 12 PM | 3 PM to 5 PM |
| In between | 9 AM to 12 PM | 4 PM to 6 PM |
| Evening leaning | 11 AM to 2 PM | 5 PM to 8 PM |
| Night owl | 1 PM to 4 PM | 7 PM to 11 PM |
Typical windows. Find your type with the chronotype quiz.
What to do when
- At your peak: the hardest analytical work: writing, design, problem-solving, studying new material.
- In the dip: routine tasks: email, admin, simple meetings, tidying up. Or a 20-minute nap.
- On the way back up: collaboration, calls, review, and creative work. Some research suggests insight problems can be easier when you're slightly off-peak and less focused.
Planning a day around it
- Block your peak in the calendar first, every day, and protect it.
- Push meetings into the dip or the late afternoon wherever you can.
- Keep your wake-up time steady, weekends included, so the peak stays where it is.
- Use the peak for long sessions: the deep work timer's 90/20 suits it.
When your schedule fights your clock
Owls with 8 AM starts get the worst of it: their peak lands late in the working day, and the mismatch between weekday and weekend sleep creates social jet lag. Morning light, dim evenings and a regular wake-up time can pull your clock earlier by an hour or so. Beyond that, if you have any control over your hours, use it.
Fly at your peak
In Flight, a focus session is a real flight. Book a long one for your best hours, and save the short hops for the afternoon dip.