Pomodoro and work breaks: what timed blocks can and can't do

You set a timer for 25 minutes, as the Pomodoro technique says. Some days it carries you through a dull task. Other days the bell rings just as you have got going. The research on timed blocks and breaks is more modest than the advice, and still useful.

What the evidence says

Attention can fade within one sitting. Twenty-nine adults with ADHD and 30 adults without it took four 20-minute attention tests. The adults with ADHD showed medium-sized sustained attention deficits on measures of alertness, selective attention and divided attention ¹. In a study of 96 children aged 9 to 13, 42 of them with ADHD, the authors concluded that time-on-task effects in children with ADHD were specific to attention, and seemed to come from both depleted executive resources and depleted motivation ².

Short breaks leave people a little less tired. A meta-analysis found small effects of micro-breaks: more vigour and less fatigue. The effect on overall performance, across 15 samples and 1,132 people, was not statistically significant ³.

Longer breaks did more for performance. In the same analysis, the longer the break, the greater the boost to performance. The authors wrote that recovering from highly depleting tasks may need breaks of more than 10 minutes ⁴.

Fixed blocks against breaks you choose: the results are mixed. In a one-day study of 87 university students, those who chose their own breaks had longer sessions and breaks, with more fatigue and distractedness and less concentration and motivation than students on fixed schedules ⁵. In a second, with 94 students, Pomodoro breaks led to a faster rise in fatigue than self-chosen breaks, yet overall fatigue and motivation did not differ between the groups ⁶. In a third, with 176 students, self-chosen breaks led to more positive moods, including higher energy and concentration and lower distraction ⁷. None of the three found a difference in task completion or test performance ^{5 6 7}.

What we don’t know

We found no trial of the Pomodoro technique, or of any timed-block method, in adults with ADHD. The break studies above are not described as studies of people with ADHD. The two attention studies used laboratory tests, not everyday work.

The evidence is thin. A scoping review of the Pomodoro literature included three randomised controlled trials, five quasi-experimental studies and 24 observational or comparative ones. Across the three trials, with 87 participants in total, structured intervals of 24 minutes of work and 6 of rest, or 12 and 3, led to about 20% lower fatigue than self-paced breaks ⁸.

None of these studies shows that 25 minutes is the right length.

Things to try

• Treat the block length as a setting, not a rule. On ratings of mood and fatigue, fixed blocks came out ahead in one student study and self-chosen breaks in another ^{5 7}. If one length does not fit, change it.
• Judge a break by how tired you feel afterwards. What short breaks changed was fatigue and vigour, and only by a small amount ³.
• After demanding work, try a longer break. The meta-analysis authors suggest more than 10 minutes may be needed ⁴. That is their reading, not a tested rule.