Sleep Restriction: A Counterintuitive but Effective Technique

Sleep restriction therapy is a component of Cognitive Behavioural Therapy for Insomnia (CBT-I) that, despite its counterintuitive name, is one of the most effective interventions for chronic insomnia. The technique involves temporarily restricting the time you spend in bed to match the amount of time you actually spend sleeping, then gradually extending this window as your sleep efficiency improves.

Many people with insomnia respond to poor sleep by spending more time in bed — going to bed earlier, lying in longer, or napping during the day. Whilst understandable, this behaviour actually worsens insomnia by diluting the sleep drive (the biological pressure to sleep that builds during wakefulness), creating an association between the bed and wakefulness, and fragmenting sleep across longer periods with more awakenings.

To implement sleep restriction, you first keep a sleep diary for one to two weeks to determine your average total sleep time. If you are sleeping an average of five and a half hours per night but spending eight hours in bed, your sleep window is set to five and a half hours (with a minimum of five hours for safety). You choose a fixed wake-up time (for example, 7:00 a.m.) and calculate your bedtime backwards (1:30 a.m.). You must get up at the fixed time regardless of how much you slept, and you must not nap. When your sleep efficiency (the percentage of time in bed spent sleeping) reaches 85 per cent or higher for five consecutive nights, you extend the sleep window by fifteen minutes.

The first week of sleep restriction is typically difficult — you may feel more tired than usual. However, the temporary sleep deprivation builds a strong sleep drive that consolidates your sleep into a single, uninterrupted block. Most people see significant improvements in sleep quality within two to four weeks. This technique should ideally be implemented under the guidance of a therapist trained in CBT-I.