YOU MIGHT STRIVE to go to bed by 9 p.m., hoping to get a good night’s sleep. But if you lie awake for hours before drifting off, your sleep efficiency might be lacking, and it's probably interfering with your ability to get enough rest.
Sleep efficiency refers to the amount of time you spend actually asleep versus the time you spend in bed intending to sleep, explains Zachary Strumpf, M.D., a pulmonary, critical care, and sleep medicine physician at University Hospitals in Cleveland, Ohio.
“It’s different than getting a better night’s sleep and reflects how effective you are at falling and staying asleep,” he says. Sleep efficiency is expressed as a percentage, and it can vary from person to person.
Having a good sleep efficiency doesn’t necessarily mean that you’re getting good sleep, however, says Nishay Chitkara, M.D., director of sleep medicine at NYC Health + Hospitals/Bellevue.
“For example, if one is sleeping only five hours per night, the sleep efficiency may be great, but the time asleep is not sufficient,” he says. You need to get enough sleep, as well, and address any problems that are causing sleep disruption.
This is crucial, as a third of Americans don’t even get seven hours of sleep a night, the minimum recommended amount for adults, according to the Centers for Disease Control and Prevention.
Sleep efficiency can be affected by many things, including diet, exercise levels, sleep schedules, and sleep environments, Dr. Chitkara says. It’s important to know how to calculate sleep efficiency and what you can do to improve it, which will contribute to feeling more rested.
How Do You Calculate Sleep Efficiency?
SLEEP EFFICIENCY IS the ratio of the time you spend asleep relative to the time you dedicate to sleep, Dr. Chitkara explains. To calculate it, divide the total minutes you’re asleep by the total minutes spent in bed trying to go to sleep.
If you usually go right to sleep after climbing into bed, your sleep efficiency is likely good, Dr. Strumpf says.
Generally, sleep efficiency of 85 to 90 percent or greater suggests that you have little trouble falling and staying asleep, he says. But if it’s lower than 80 percent, you likely have poor sleep efficiency.
“A lower sleep efficiency likely needs improvement, since it could indicate that someone is not sleeping well, has poor sleep habits, or may have a medical condition that interferes with healthy sleep,” Dr. Chitkara says.
Sleep efficiency can also decline with age, Dr. Strumpf says. Research shows that sleep efficiency below 80 percent increases mortality risk for older people, and pain, sleep medication use, and bad dreams are the main factors for their poor sleep efficiency. Men between the ages of 65 and 96 were more likely to have low sleep efficiency when they were single or had a painful illness.
It might seem like taking sleep medications would increase sleep efficiency, but Dr. Strumpf says they can actually alter various aspects of sleep depending on the person. "Certain medications can increase or decrease a person’s sleep efficiency or alter the proportion of time spent in REM sleep," he says.
Working with a sleep doctor includes recommending medications and reviewing the effects they could have on your sleep, Dr. Strumpf says.
How to Improve Your Sleep Efficiency
YOU CAN GENERALLY improve your sleep efficiency by optimizing your sleep hygiene, Dr. Chitkara says. “Sleep hygiene is the set of practices that are conducive to good sleep.”
These practices include:
- Maintaining a regular sleep schedule—that is, going to bed and waking up at the same times daily
- Getting seven to eight hours of sleep a night
- Avoiding caffeine late in the day
- Going alcohol-free three to four hours before sleep
- Avoiding watching TV or scrolling your phone an hour prior to sleep
- Cutting out napping
Spending less time in bed when you’re not ready to fall asleep is another way to increase sleep efficiency, Dr. Strumpf says.
“However, a higher sleep efficiency is not the only thing to target for restful sleep,” he says. You also need adequate sleep duration, meaning staying asleep for a long stretch, ideally at least seven hours.
“Ensuring adequate sleep duration and good sleep efficiency will allow your brain to naturally cycle through all the stages of sleep you need,” Dr. Strumpf says. These stages are controlled by the systems in the brain and usually can’t be influenced with behavioral changes.
Can Sleep Trackers Help?
SLEEP TRACKER APPS or other devices could help improve sleep efficiency by providing information and insights into your sleep habits, which you can use to make improvements, Dr. Chitkara says.
For instance, they can keep track of light, temperature, noise levels, and other environmental elements influencing your sleep, as well as caffeine intake and stress levels, he says. Trackers can also record health metrics, such as heart rate, movement, body temperature, and blood oxygen levels.
When to See a Doctor
ANY TIME YOU’RE having trouble falling or staying asleep, waking up several times a night, or feeling excessively sleepy throughout the day, talk to your doctor, Dr. Strumpf urges. Your doctor may refer you to a sleep specialist.
It’s especially important to get evaluated if these symptoms last for more than three months or if your bed partner is complaining that their sleep is disrupted, Dr. Chitkara says.
Also get checked out if you notice any symptoms of sleep apnea, a dangerous condition where you constantly stop and start breathing when you sleep, Dr. Strumpf says. These signs include snoring, gasping or choking during sleep, or periods of not breathing when you’re asleep.
