You have probably heard that the morning is the time for deep work. That’s fine if you are a morning person. It helps less if you are not, if your mornings belong to meetings, or if your afternoons always feel dead.
So when should you do deep work? Here you get what the research on time of day supports and how to check your state before each block. Then you’ll see which task goes where, what to do after lunch and how to find your own best hours.
What does research say about the best time of day for deep work?
Research shows that time of day matters for thinking, and that how it matters depends on the person. No clock hour comes out of it that fits everyone.
Three studies are worth knowing. Each looked at a different part of the question:
| Study | What it looked at | What it found |
|---|---|---|
| Schmidt et al., “A time to think” (2007) | Attention, executive function and memory in healthy adults (review) | Effects depend on whether you work at your own peak |
| Monk, “The post-lunch dip in performance” (2005) | Performance in the early afternoon | A mid-afternoon dip in some people, even without lunch |
| Wieth and Zacks, “Time of day effects on problem solving” (2011) | Insight and analytic puzzles | Insight puzzles solved better at the non-optimal time of day |
The first finding is about your chronotype, your natural timing as a morning or evening type. It shapes when your thinking works best. The review’s summary gives no clock hours.
So ask when you are at your peak, and how you can tell on a given day.
What are the cognitive peak hours to do deep work?
Whatever your peak hours turn out to be, a block needs you rested and awake. You check that before each block, not on a chart.
Being rested is the prerequisite, because without mental fitness no Deep Work Block will work.
So do an honest self-check before every block: are you awake, and can you think clearly? The answer decides what the block looks like:
- Fit: 45 or 90 minutes, full power
- Not quite fit: shorter block or activate your body first
- Massively tired: power nap (10–20 min.) or postpone the block
A chart of hours can’t see a bad night or a heavy head. That’s why this check tells you more than any table of hours. It also helps you decide whether you should do deep work in the morning at all.
Match the task and the block length to your energy
Even on a good day, your energy doesn’t stay the same from morning to evening. So put demanding work where your energy is and easier work where it fades, and let the block length follow.
Maybe you manage 45 or 90 minutes in the morning, and only 25 in the afternoon. Wasting energy on an easy task is just as inefficient as doing a hard task without energy.
Which energy level you have at which time of day is a big topic of its own. I don’t cover it in the book.
Your low hours still have a use. In the study by Wieth and Zacks (2011), people solved insight problems better at their non-optimal time. These are puzzles that need a sudden idea.
Analytic problems showed no consistent effect.
The authors suggest creative tasks might benefit from a non-optimal time. One puzzle study doesn’t overturn the energy rule. But your off-peak hours aren’t wasted.
Can you do deep work after lunch?
Often yes, but the early afternoon is where a block needs the most help. Monk (2005) describes a mid-afternoon dip in performance in some people, linked to higher sleepiness.
The dip can occur without lunch, and a high-carbohydrate lunch makes it worse. It may also be more likely in extreme morning types.
Food matters because after large meals, your body needs energy to digest, and that energy is missing from your brain. The book has no chapter on the afternoon dip. But you can apply its preparation steps for any block to the afternoon block:
- Eat light: a snack between blocks is fine, a full meal kills the next block.
- Fresh air: open the window for 3 minutes before the block.
- Water: drink a large glass of water before the block.
- Move: do 50 jumping jacks or 20 squats right before you start.
Working tired can be worse than not working at all. If the afternoon block still won’t go, give that hour to easier tasks. And if meetings and email fill your afternoons anyway, schedule deep work around them.
How do you find your own best time for deep work?
Your best time shows in your results, so test it on your blocks instead of guessing from a chart.
You could rate your energy for a few weeks. That would show the best time of day to schedule deep, focused work. But a rating measures a feeling, not what you got done.
In the book, I give a simple test for coffee: “Don’t compare the feeling, compare the actual work output.” Your protocol sheet is the page next to you during a block. Applied to time of day, the coffee test becomes a small test with it:
- Write each block goal on your protocol sheet, as usual.
- Note the start time next to it (my addition).
- Check the goal when the timer goes off: reached, partially, or not at all.
- Keep your sheets for a few weeks (the book makes that optional), then check when your blocks reached their goals.
If your job fixes the hours, see deep work in a full-time job. For a simple log, see how to track deep work. For the week, see which days are best for deep work.
Over time you learn what you can realistically accomplish in a day. Don’t count blocks, look at results: two blocks with good results are better than five you just dragged yourself through.
Your best time shows up one block at a time on the sheet. Run each block the same way, and in a few weeks the sheet tells you when your blocks work best. See how it works →
FAQ
Should you do deep work at the same time every day?
Deep work doesn’t need a fixed start time, and your blocks don’t have to start on the hour. Some people like a fixed schedule, others feel pressured by it. Find out what works for you, because what counts is that the blocks happen.
Does coffee change the best time for deep work?
Caffeine masks tiredness without fixing it, so it doesn’t replace being rested before a block. The tiredness can hit later as a crash. Test it with one block with and one without coffee on different days, and compare the output, not the feeling.
Can you do deep work late in the evening?
Some people find their best hours for deep work late at night. My own rule comes from the end of the workday: once it’s over, the evening is for recovery. Anyone who keeps working in the evening pays for it the next morning.
