What is sleep restriction?
Sleep restriction is a technique where you temporarily limit the time you spend in bed to the number of hours you actually sleep. It sounds counterintuitive: you’re already sleeping too little, and now you have to spend even less time in bed? Yet it’s one of the most researched and effective methods against chronic insomnia.
The technique was developed in 1987 by Arthur Spielman and has been part of every CBT-I treatment since. The idea is simple but powerful: by restricting your bedtime, you build natural sleep pressure. And the greater your sleep pressure, the faster and deeper you sleep.
The problem sleep restriction solves
Many people with insomnia make the same mistake: they go to bed earlier and stay in bed longer, hoping to catch more sleep. The result is exactly the opposite. You lie awake for hours in bed. Your brain learns that bed is a place for rumination, not for sleeping. Your sleep efficiency (the ratio between sleep time and time in bed) drops to 50-60%, while healthy sleepers sit above 85%.
Example: you go to bed at 22:00 and get up at 7:00. That’s 9 hours in bed. But you only sleep 5.5 hours. The other 3.5 hours you lie awake, frustrated, staring at the ceiling. Every night your brain reconfirms: bed = lying awake.
How sleep restriction works: step by step
Step 1: determine your average sleep time
Keep a sleep diary for two weeks. Note each morning: when you went to bed, when you fell asleep (estimate), how often you woke up, when you got up. Calculate your average total sleep time. Let’s say that’s 5.5 hours.
Step 2: set your sleep window
Your sleep window equals your average sleep time, with a minimum of 5 hours. Pick a fixed wake-up time (for example 7:00) and count back. At 5.5 hours sleep time: you can only go to bed at 1:30. Everything before that, you do outside the bedroom.
Step 3: stick strictly to the schedule
Don’t go to bed before your planned bedtime, even if you’re dead tired. Get up at the fixed time every morning, even if you slept poorly. No daytime naps. This is the hardest phase, but also the most important.
Step 4: calculate your sleep efficiency
After a week, calculate your sleep efficiency: (total sleep time / time in bed) x 100%. If it’s above 85%, you can move your bedtime 15 minutes earlier. Below 80%? Then your sleep window stays the same or shrinks by 15 minutes.
Step 5: gradual expansion
Every week that your sleep efficiency stays above 85%, you shift your bedtime 15 minutes earlier. This way you slowly build up to optimal sleep duration. Most people reach their natural sleep need (7-8 hours) within 6 to 10 weeks.
Why does it work so well?
Sleep restriction works through three mechanisms:
1. Increased sleep pressure: by spending less time in bed, you build up more adenosine (the substance that makes you sleepy) during the day. You fall asleep faster and sleep deeper.
2. Retraining the bed-sleep association: your brain learns again that bed is a place where you sleep, not where you lie awake. After a few weeks you feel your body automatically relax as soon as you step into bed.
3. More stable biological clock: the strict schedule regulates your circadian rhythm. You get sleepy and wake up at predictable times.
What to expect
Week 1: hard
The first week is the hardest. You’re tired during the day, sometimes even exhausted. Your concentration is lower and your mood can be variable. This is normal and temporary. It’s a sign that sleep pressure is building up.
Week 2-3: breakthrough
After 7 to 14 days, most people notice a difference. You fall asleep faster (often within 10 minutes), you sleep through the night, and your wakefulness in bed is drastically reduced. Your sleep efficiency rises to 85-95%.
Week 4-8: stabilisation
Your sleep window gradually expands. Your sleep becomes more stable and predictable. Many people describe this as the first time in months (or years) that they really sleep through.
Important: safety and contraindications
Sleep restriction is safe for most people, but there are exceptions:
- Epilepsy: sleep deprivation can trigger seizures. Sleep restriction is not recommended.
- Bipolar disorder: sleep deprivation can trigger a manic episode. Only under strict medical supervision.
- Safety-critical occupations: if you work with heavy machinery, drive for a living, or perform medical procedures, discuss sleep restriction with your therapist first.
- Severe sleep apnoea: must be treated first before sleep restriction is worthwhile.
Preferably do sleep restriction under the guidance of a sleep therapist. At SlaapWel our therapists work with a structured sleep restriction protocol, tailored to your situation.
Sleep restriction vs. sleep hygiene
Sleep hygiene (cool bedroom, no screens, fixed rhythm) is valuable as prevention, but for chronic insomnia it’s rarely sufficient. Sleep restriction tackles the core of the problem: the disrupted association between bed and sleep, and the low sleep pressure from too much time in bed.
Think of sleep hygiene as the foundation and sleep restriction as the active treatment. You need both, but sleep restriction delivers the real difference.
Frequently asked questions about sleep restriction
Isn’t 5 hours of sleep unhealthy?
In the short term, 5 hours is little, but it’s temporary. The goal isn’t to permanently sleep less, but to raise your sleep efficiency. As soon as it’s above 85%, you expand your bedtime. After 6 to 10 weeks you sleep 7 to 8 hours again, but consolidated and of higher quality.
Can I take a nap during sleep restriction?
No. Naps lower your sleep pressure and undermine the whole process. If you’re extremely tired during the day, go outside, move, seek daylight. The fatigue is temporary and a sign that the method is working.
What if I don’t sleep at all one night?
That can happen, especially in the first week. It’s unpleasant but not dangerous. Get up at your fixed time and stick to the schedule. Your sleep pressure will be extra high the next night, so you’ll sleep better.
Can I combine sleep restriction with melatonin?
You can, but discuss it with your therapist. Melatonin can help with falling asleep when your sleep window starts, but it doesn’t replace the action of sleep restriction itself. Use a low dose (0.3 to 0.5 mg) about 1 to 2 hours before your planned bedtime.