How are sleep and anxiety connected?

By Aamir Malik, PhD, Professor of Neuroengineering at Brno University of Technology

Published 21 October 2026 · Updated 21 October 2026

This guide shares wellness information to use alongside your doctor, never instead of one.

Why do worries feel bigger after a bad night?

In a 2007 study, researchers scanned the brains of young adults as they looked at upsetting pictures. After a normal night, the amygdala, the brain’s fear center, reacted in proportion, held in check by the thinking part of the brain just above it. After a night without sleep, it fired about 60 percent harder, and the calming link to the thinking brain had gone quiet.

So if everything feels harder, sadder and more irritating after a bad night, that is not a weakness of character. In the book’s words: “That’s your emotional brakes, unserviced.”

Why do I wake at 3 a.m. feeling anxious?

Partly, it is your body clock. Cortisol, the hormone that gets you up, starts rising in the second half of the night to prepare you for the morning. Waking briefly in the night is normal; everyone does it several times. The trouble starts when a worried mind grabs that natural rise in alertness, and you lie there counting the hours until the alarm.

What helps:

• Don’t look at the clock, and don’t reach for your phone.
• If you are still awake after what feels like twenty minutes, get up. Go to another room, keep the lights low and do something dull. Write down what is on your mind. Go back to bed when you feel sleepy.
• Keep the bedroom cool, and go easy on fluids late in the evening.

What helps when my mind races at bedtime?

• Empty your head onto paper. In a 2018 study at Baylor University, people who spent five minutes before bed writing a to-do list for the next day fell asleep about nine minutes faster than people who wrote about what they had already done. The list takes the open loops out of your head.
• Breathe slowly. Breathe in for about four seconds and out for about six, for five to ten minutes. The longer out-breath is the part that calms you.
• Stop trying. You can’t force sleep. As the book puts it: “Sleep is a cat, not a dog. It comes when you make the room safe and quiet and then stop chasing it.”

What helps both during the day?

The book’s plan is to work on sleep, food and exercise together, because they run as one machine. Fix one alone and it tends to disappoint.

• Sleep: the same wake time every day, weekends included; bright light soon after waking; a real wind-down without screens; a cool, dark room with the phone outside it.
• Exercise: one of the most reliable sleep aids there is, and the strongest single lever the book found for anxiety and low mood. A 2025 review of 22 trials found that regular exercise meaningfully eased insomnia. A 2024 review in the BMJ, pooling hundreds of trials, found that exercise meaningfully reduced depression, holding up in comparison with talking therapy and antidepressants.
• Exercise timing: finish anything hard at least four hours before bed, or it can steal the sleep it should deepen. Expect the first week to ache; by the second or third week, the ache fades and you start to want it.
• Caffeine: move it earlier, roughly six to eight hours before bed. If anxiety is part of your picture, cut the amount too: the extra cups you drink to get through a flat day can tip you into a wired, on-edge state.
• Food: don’t under-eat, choose whole foods over ultra-processed ones, include oily fish for omega-3 fats, and ease off added sugar and sugary drinks. A heavy, sugary or fatty meal late at night breaks up sleep.
• People: loneliness keeps the body’s stress alarm switched on, day and night. The isolated nervous system stays half on guard and sleeps lightly. One call, or one standing walk or meal each week, starts to settle it.

Give it two to three weeks. A drifting body clock resets on the third week, not the first, so judge it then, not on night two.

Talk to your doctor if

• sleep still won’t come right after a few weeks of honest changes. Ask about cognitive behavioral therapy for insomnia (CBT-I). The book calls it the drug-free gold standard: more effective over the long run than sleeping pills, without the fog and the dependence.
• you snore loudly with gasping or choking, someone has seen you stop breathing, or you are very sleepy in the day however long you slept. That points toward sleep apnea, which no wind-down can fix and which can be helped once it is found.
• you ever fall asleep without meaning to, mid-conversation or at the wheel. That is urgent.
• anxiety or low mood is severe, or doesn’t lift after you have honestly worked on all five pillars. Talking therapy and medication are real, effective options for many people, and they sit alongside these changes, not instead of them.
• you take an antidepressant and want to change it. Don’t stop or change it because of anything here; stopping suddenly can bring real withdrawal effects, and any change belongs with your doctor.
• your mood feels truly dark, or you have any thought of harming yourself. Please don’t wait, and don’t sit with it alone. Reach out today, to a doctor, a crisis line or someone you trust. If you are in immediate danger, call your local emergency number.

Fix the Floor comes with a home self-assessment, about fifty minutes, that shows you which of your five pillars to fix first.

Fix the Floor: Your health breaks at its weakest link. Find yours. Fix it.

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