Sleep restriction therapy (SRT) is an insomnia treatment that aims to improve a person’s sleep quality by limiting the time they spend in bed.

Adults need 7 or more hours of sleep per 24 hours. However, many people have difficulty getting enough sleep.

A person with insomnia finds it difficult to fall asleep or stay asleep throughout the night. Research suggests that 1 in 4 people in the United States experience acute insomnia every year, while about 10–30% of adults worldwide have chronic insomnia.

Some people may find that restricting the time they spend in bed trying to sleep may lead to fewer awakenings and more consolidated and efficient sleep.

This article explores sleep restriction therapy, including how it works, its steps, its effectiveness, and more.

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SRT aims to help people achieve a good night’s sleep by reducing the number of hours they spend in bed. The premise is that the more time a person spends lying in bed unable to sleep, the more they feel negative, stressed, and pressured.

These negative beliefs make people dread the time they spend lying awake, making falling and staying asleep much harder to achieve. A person may spend hours lying awake in frustration and wondering how to achieve better sleep.

SRT is a behavioral treatment that addresses this pattern of worrying. It is a method that forms part of cognitive behavioral therapy for insomnia (CBT-I).

Learn about other treatments for insomnia.

The idea is that by limiting the time they spend awake in bed, a person can shorten the time it takes for them to fall asleep and improve their overall quality of sleep. This approach helps by:

  • Building homeostatic sleep drive: The less time a person spends in bed, the more tired they become. This builds up sleep pressure, or the drive to sleep, which increases the chance of a good night’s sleep.
  • Resetting the circadian rhythm: SRT realigns the behavioral timing of sleep, meaning the time that a person attempts to sleep, with the body’s circadian rhythm. This helps the individual follow bodily triggers of sleepiness and wakefulness.
  • Decreasing body and cognitive arousal: SRT decreases pre-sleep arousal and increases sleep pressure before a person goes to bed. Pre-sleep arousal refers to physical and mental processes, such as a rapidly beating heart and racing thoughts, which may stop a person from falling asleep.
  • Reduces negative thinking patterns: A 2019 study also found that SRT significantly reduced maladaptive thinking, depression, and hyperarousal, leading to better sleep in postmenopausal women.

The administration of SRT varies from person to person, depending on personal factors such as:

  • age
  • medication history
  • lifestyle factors
  • other preexisting medical conditions

An SRT practitioner may recommend the following steps:

Step 1: Identify average total sleep time using a sleep diary

A person will work with a sleep therapist who will ask them to keep a sleep diary for 1–2 weeks. In the diary, they should record how long they spend in bed and estimate the length of time they sleep each day.

For example, a person may spend 9 hours in bed each night but only sleep for 6 hours.

They should also take note of factors that can disturb their sleep, including:

  • exercise
  • use of mobile phone
  • coffee consumption
  • needing to use the bathroom
  • other sleep disturbances

Step 2: Determine the sleep window

The sleep specialist will determine the maximum time that a person can spend in bed based on their average total sleep time, or sleep window, per week.

For example, a person who goes to bed by 10 p.m. and wakes up by 8 a.m. but only sleeps on average for 6 hours per night should restrict their sleep window to 6 hours. They could, therefore, go to bed at 11.30 p.m. and get up at 5.30 a.m.

However, practitioners advise that people do not restrict their time in bed to less than 5 hours regardless of their average sleep time.

Step 3: Set a waking up time

A person should select a time to wake up every morning — the same time each day — and stick to it regardless of how much sleep they had the night before.

Learn more about fixing a sleep schedule.

Step 4: Set a bedtime

Individuals can determine their bedtime by counting backward from their wake time to fit in their sleep window.

For example, if a person has decided to wake up every day at 7 a.m. and has a 6-hour window, they should go to bed at 1 a.m.

Step 5: Stick to the schedule for about 2 weeks

A person should commit to following their schedule for about 2 weeks while continually tracking their time in bed and asleep.

Step 6: Calculate the average efficiency score

A person can calculate their sleep efficiency (SE) score by dividing the time they spend asleep by their time in bed and multiplying it by 100 to get a percentage. Both of these times should be in minutes.

Step 7: Adjust the sleep window

A sleep specialist then uses a person’s weekly average SE score to determine the need to adjust their sleep window.

When a person’s sleep efficiency is higher than 90%, or 85% in older adults, the sleep specialist can increase their time in bed by 15–30 minutes. A person’s permitted time in bed becomes 15–30 minutes shorter when their SE score is 80–85%.

Sleep specialists will follow each change for at least a week before making another adjustment. This continues until no further change is necessary because the person has already reached their recommended amount of sleep, or the amount of sleep they are getting is enough for optimal functioning during the day.

A person using SRT can take extra steps to overcome insomnia. These include:

  • Avoiding napping: Taking naps during waking hours will decrease the sleep drive, making it difficult to sleep at bedtime.
  • Using light: Light is one of the most powerful controllers of the body clock. A person can use a bright light — either natural light or a lightbox — in the morning and dim light or no light in the evening. Exposure to light can help reset the sleep-wake cycle.
  • Practicing good sleep hygiene: A person should aim to adopt habits and practices that can help promote sleep, including doing regular exercise, eliminating nicotine and caffeine, and avoiding eating heavy meals too close to bedtime.
  • Remembering that willpower, consistency, and persistence are essential: It can be challenging to wake up and sleep at a set time every day. Adopting the right mindset from the beginning can help maximize the likelihood of SRT being effective.
  • Embracing a routine: Adopting a consistent routine can help prepare the body for bed. A person can begin by adding habits that signal to their body that it is the morning. Examples include showering and walking outdoors.
  • Using the bed only for sleeping and sex: A person should avoid working, watching movies, or spending time browsing social media while lying on their bed.
  • Creating a cozy sleeping environment: Sleeping in a cool, quiet, and dark room can help signal to the body that it is time to sleep by triggering the release of melatonin, the hormone that promotes sleep.
  • Expecting an increase in daytime sleepiness, especially early in the SRT treatment: It is best not to operate heavy machinery or drive when this occurs.

Learn more about sleep hygiene.

SRT is a crucial part of CBT-I and an effective treatment for people with insomnia with either short or typical sleep duration. In a 2019 study, it also significantly improved sleep efficiency in both online and outpatient clients.

A 2021 study showed that SRT offers short-term improvements in sleep continuity and insomnia severity in people with chronic insomnia.

Similarly, a 2019 study on the effects of CBT-I on postmenopausal women with insomnia found that it improved quality of life, work productivity, daytime fatigue, energy, and self-reported sleepiness.

Here are the answers to a couple of frequently asked questions about SRT.

How long does sleep restriction therapy take to work?

There is no fixed time frame for sleep restriction therapy to work, but it generally takes about 2–8 weeks of consistency and commitment to sticking to the technique and a fixed sleep schedule.

Does sleep restriction therapy cure insomnia?

SRT is usually the first line of treatment for insomnia. It improves sleep efficiency by reducing the time a person spends in bed.

SRT is often part of CBT-I, but it may be available as a stand-alone therapy. Here are several ways a person can access sleep restriction therapy:

  • a referral from a doctor from their network
  • self-referral for psychological therapies near the person’s location
  • private face-to-face practitioners
  • online sleep therapy programs
  • CBT-I-based apps for self-practice

Learn about long-distance CBT for insomnia.

The early stages of SRT may be challenging and cause irritation and excessive daytime sleepiness. However, this does not last long. Diligence and consistency in following the sleep schedule can help a person get better quality sleep within weeks.

Although it can be effective, SRT is not for everyone. People who have serious sleep disorders or other significant health issues and those who are pregnant should consult a doctor before starting the treatment.

Moreover, people with certain occupations, including drivers and operators of heavy machinery, should be cautious about the possibility of daytime sleepiness.