Food, exercise and screens
The three evening habits people argue about most. Learn what a late dinner really does, when exercise helps and when it doesn't, and why screens cost you more time than light.
FOOD
A big meal lying down
Digestion doesn't pause because you went to bed. A large late meal keeps your gut working, nudges your core temperature up at the hour it should be coming down, and puts a full stomach horizontal, which is when reflux happens: acid moving back up your throat. You may not wake up fully, but the night gets lighter and more broken.
This is why people so often wake around 2am after a heavy, late, oily dinner and blame stress. Try it after a small one and see whether the 2am wake-up comes.
Working rules for the evening meal
- Aim to finish the main meal about two to three hours before bed. For an 11pm bedtime that's dinner by 8 or 9.
- Don't go to bed hungry either; an empty stomach wakes people too. Something small and plain an hour before is fine: bread and cheese, yoghurt, a few dates, a banana.
- If you get reflux, the usual culprits are large, fatty, fried or heavily spiced meals late at night. Raising the head of the bed a little helps some people.
- Go easy on fluids in the last hour or two, so the bathroom doesn't take a trip out of your night.
Check yourself
Ramin gets home from work at 10pm and eats a full dinner at 10:30, then goes to bed at 11:15. He falls asleep quickly but wakes around 2am with heartburn. What should he change first?
- Keep the same dinner and push bedtime to 12:15 so it has time to settle
- Skip dinner on late nights, so there's nothing left to digest
- Eat the main meal earlier, and have something small and plain at 10:30 if he's hungry
- Keep the same dinner and have a strong tea with it to help it down
Show the answer
Eat the main meal earlier, and have something small and plain at 10:30 if he's hungry
Yes. The problem is a full stomach going horizontal 45 minutes later. Moving the big meal earlier and keeping a light snack for late nights fixes the reflux without costing him sleep.
EXERCISE
The most reliable thing on the list
Of everything in this course, regular exercise has some of the strongest evidence behind it. People who move regularly fall asleep faster, sleep more deeply and wake less. It works partly by raising sleep pressure and partly by taking the edge off stress and low mood. The effect builds over weeks, not from one session.
Nothing dramatic is needed. A brisk 30-minute walk most days, or a couple of longer sessions a week, is enough to show up in your sleep.
Check yourself
For most people, a workout in the evening is better for sleep than skipping exercise altogether.
Show the answer
True
True. Exercise at any time of day beats no exercise, and plenty of people sleep well after an evening session. Treat it as an experiment: if a hard workout finishing an hour before bed leaves you buzzing, move it earlier. If it doesn't, keep it. A walk or gentle stretching after dinner suits almost everyone.
SCREENS
Two problems, not one
Screens hurt sleep in two separate ways, and almost all the public argument is about the smaller one. The light holds melatonin back a little, as you saw in lesson 4. What you're doing matters more: messages, work, news, arguments and games keep the alerting system switched on, and they are designed to make the next minute feel necessary.
A paper book by a dim lamp and the same book on a phone are not very different. The same phone with your work group chat open is a different thing entirely.
Plan: lights out 11:00pm, alarm 6:45am
11:02 five minutes of messages
11:19 a video someone sent
11:44 comments, then another video
12:10 lights out
lost tonight = 70 minutes
five work nights = 70 x 5350 minutes a week, about one whole night of sleepNothing there was a decision, and the alarm never moved, so every minute came out of sleep. This is the expensive part of screens, and it has nothing to do with blue light.
Check yourself
- Golnaz reads a paper novel for 40 minutes under a dim lamp and is asleep by 11:15.
- Golnaz reads work messages on her phone at its lowest brightness for 40 minutes and is still awake at 12:30.
The light was low in both cases and the time was the same. What made the difference?
- A phone is always worse than paper, whatever is on it
- Forty minutes of reading is simply too long before bed
- What she read pulled her into problems and decisions, which keeps the alerting system on
- She held the phone closer to her face than the book
Show the answer
What she read pulled her into problems and decisions, which keeps the alerting system on
Yes. Same device brightness, same duration, different content. Work messages hand you problems you can't act on at 11pm, and your body stays ready to deal with them.
Two versions of the same evening
The evening that works
Dinner at 8. A walk after it. Shower at 9:30. Phone on charge in the hall at 10:15, then a book under one lamp. In bed at 11, asleep by 11:20.
The evening that doesn't
Dinner at 10:30, heavy. Gym finishing at 10:45 some nights. In bed at 11 with the phone, work chat open, then videos. Asleep at 12:30, alarm still at 6:45.
Check yourself
Elham trains at the gym from 9 to 10:15pm, gets home, showers at 10:40, then scrolls in bed until 12:30. Her alarm is 6:30. She's decided the gym is wrecking her sleep and is about to quit. What's actually costing her the most?
- The gym session, because a hard workout that late always leaves you too wired to sleep
- The two hours on the phone in bed, which pushed her bedtime back
- The shower, which warms her up right before she gets into bed
- Her chronotype, which can't be changed and makes late nights inevitable
Show the answer
The two hours on the phone in bed, which pushed her bedtime back
Right. The gym takes a fixed 75 minutes and finishes well before bed. The phone took two hours out of her night and kept her alert while it did it. Quitting the gym would remove the one habit that's helping.
Check yourself
Match each habit to the mechanism behind it
Show the answer
- A heavy, oily dinner at 10:45pm → Digestion and reflux breaking up the early cycles
- A hard workout finishing at 10:50pm → Core temperature up when it should be falling
- Scrolling in bed until 12:30 → A bedtime that moved, not just a brighter room
- A walk after dinner → More sleep pressure and less stress by bedtime
Lesson recap
- Finish the main meal two to three hours before bed, and don't go to bed hungry either.
- Regular exercise is one of the strongest sleep habits there is, and it builds over weeks.
- Evening exercise is fine for most people. If a hard late session leaves you wired, move it earlier.
- Screens cost you through light, and much more through engagement and lost time.
- Park the phone in another room at the start of your wind-down, so the decision happens once.