Head too full to sleep?
· Source: Scullin et al., Journal of Experimental Psychology: General, 2018
The light is off, the phone is face down, and your body is ready for sleep. Your head isn’t. It’s going through tomorrow: send the invoice, call the dentist, buy a present for Saturday, answer the email you’ve been avoiding since Tuesday. Each item comes back two or three times, as if afraid you’ll forget it the second you drift off.
Most people know this half hour well. Nothing big is wrong. There’s just a lot of small stuff, and nowhere to put it down.
The sleep lab study
In 2018, Scullin and colleagues at Baylor University invited people to spend the night in a sleep lab. Before going to bed, everyone wrote something. One group wrote a to-do list for the coming days. The other group wrote about tasks they had already finished.
The to-do group fell asleep faster. And within that group, the people whose lists were more detailed fell asleep faster still.
It helps to be exact about who took part. The people in this study were young and had no problems with sleep. So the result says nothing about insomnia, and it isn’t a treatment for someone who lies awake night after night. It’s about the ordinary evening described above, when a healthy sleeper’s head is simply too busy.
Why tomorrow’s list, and not today’s wins
You might expect writing about what you got done to be the calmer choice. You end the day on a good note and go to sleep satisfied. In the lab, it was the other way round.
Here is one plain way to read that, which is ours and not something the study measured. Finished tasks don’t ask anything more of you. Tomorrow’s tasks do, and as long as they live only in your head, your head keeps checking on them. A detailed list may work better for the same reason. “Call the dentist” still leaves you wondering when and about what. “Call the dentist at nine about Tuesday” leaves nothing to rehearse.
Tomorrow’s tasks keep circling until they are written down somewhere.
Worry can wait for its own time
Not everything that keeps you up is a task. Some of it is worry: about money, about a test result, about a friend who has gone quiet.
An older study looked at worry directly. In 1983, Borkovec and his colleagues asked people to set aside 30 minutes for worrying every day, at the same time and in the same place. When a worry turned up outside that half hour, people put it off until then. Over the day, they had fewer worrying thoughts.
The study didn’t look at bedtime. Still, it suggests something practical for the evening. When a worry shows up at midnight, you don’t have to settle it then. You can give it a time tomorrow, and say out loud when that time is.
The point isn’t to pretend the worry is small. It’s to give it a better place than the dark at midnight, when you can’t check anything, call anyone or fix a single thing.
“Just stop thinking about it” rarely works
The most common advice at midnight is to stop thinking. In 1987, Wegner and his colleagues asked people not to think about a white bear. The people who had tried to keep it out of their minds thought about it more often afterwards.
Later studies have been mixed about how strong this effect is. But one part of the work is useful here: when people turned their attention to something specific, the effect went away. Making a list is exactly that kind of specific job. You aren’t trying to chase the thought out. You’re giving it a place.
Planning ends, replaying doesn’t
Planning tomorrow and chewing on one worry feel alike at midnight, but they aren’t. The chewing has a name, rumination, and researchers who reviewed the evidence in 2008 found that it feeds a low mood and gets in the way of fixing the thing you’re worried about. A list moves you toward the planning kind.
A list has a last line. Once every task is on it, you’re done. Replaying has no last line, which is why the same three thoughts can fill an hour. If you notice you’re on your fourth lap of the same worry, that’s a sign to move it to tomorrow’s worry time.
It helps to keep the two jobs separate. The list is for things you’ll do: calls, errands, emails. The worry slot is for things you can’t do anything about tonight. Mixing them makes both harder, because a task on the worry pile starts to feel like a threat, and a worry on the task list has no clear next step.
One honest note. The people in the sleep study wrote their lists. Nobody has tested whether saying the list out loud works the same way. It’s a reasonable thing to try, and it’s our suggestion, not a finding.
What it might sound like
Here is an invented example of one evening, to show how short this can be. It’s Wednesday, close to eleven, and Sam is brushing his teeth when the list starts up in his head.
He says it out loud instead, while it’s all still there. “Send the invoice to Marta before ten. Call the dentist at nine and move Tuesday’s appointment. Buy a present for Jo on the way home, something for her garden. Answer the email about the flat, even if it’s just to say I need until Friday.” That takes about a minute.
Then a different kind of thought turns up: what if the flat falls through. There is nothing he can do about that tonight. So he gives it a time: “I’ll think about the flat tomorrow at lunch, for half an hour.” He doesn’t argue with the worry or try to solve it. He just tells it when.
That’s the whole routine. Two parts, a few minutes at most, done before he gets into bed.
Some small things can make it easier, and they’re suggestions rather than findings. You can do it before you lie down, so the list is finished by the time the light goes off. You can keep the same order every night: tasks first, then any worry, then stop. And if you remember something new once the light is off, add that one item and leave the rest alone. There’s no need to go through the whole list again.
What this does not promise
This is one study with young people who already slept well. It may help on a busy evening. It won’t fix long-running sleep trouble, and it won’t do tomorrow’s tasks for you.
Lying awake for hours, night after night, or weeks of poor sleep are a reason to see a doctor, and a list won’t fix that. What it can do is help the appointment: a few weeks of notes show which nights were bad and what was on your mind before them.
Try it tonight
- Before bed, take tomorrow out of your head. Say every task, small ones too.
- Make each one specific: what, who, and when.
- If a worry comes up, give it a time tomorrow and say when that is.
- Then stop. The list will still be there in the morning.
Say the list out loud in Halflight before you turn off the light. It writes it down under today’s date, so in the morning the whole list is waiting for you.