Getting seven to ten hours of sleep per night is a common prescription for health. But a number of studies indicate that it’s sleep efficiency, not duration, which determines healthy outcomes.
Sleep efficiency is the actual amount of time spent in restful sleep, not the number of hours lying in bed. It’s calculated by dividing the number of minutes spent asleep by the total number of minutes spent in the bed. According to the Hypersomia Foundation, normal sleep efficiency is around 85% or higher. Any lower, and trouble begins, on many fronts
Good Sleep and Academics
An article published in Sleep Medicine found that the better a child’s sleep efficiency, the higher their performance in school subjects.
The study monitored seven to 11-year-old kids over a five-night period and measured the kids’ movements and actual time spent asleep. The parents involved provided the most recent report cards, which were then correlated with the sleep efficiency scores.
The results were thought-provoking: better sleep efficiency led to better grades in math, English language, and French as a second language. (McGill University, the origin of the study, is in Canada, so the French language emphasis has a context.) Science and art grades remained stable.
Dr. Reut Gruber, professor of psychiatry at McGill University and co-author of the study, suggested in Futurity that sleep issues may underlie lower academic performance. He added that pediatricians should incorporate questions about sleep habits and hygiene when consulting with parents.
“I think many kids might have some sleep issues that nobody is aware of,” Gruber told Futurity. “And if the pediatrician doesn’t ask about it, we don’t know that it’s there. Regular screening for possible sleep issues is particularly important for students who exhibit difficulties in math, languages, or reading.”
Los Angeles area marriage and family therapist Margie Mirell, MFT, sees this often in her practice. “Children do not have the capacity to regulate their emotions when they do not get adequate sleep,” Mirell told Parentology.
“Recently, I was working with parents who were complaining that their daughter was falling down in her academics,” Mirell says. “In addition, the daughter was complaining that her friends told her she was being mean. When I questioned the parents more about the daughter’s evening schedule, it was discovered that the daughter was spending more and more time on social media and texting with her friends.”
Mirell’s solution was simple and elegant. “I made a suggestion for a new schedule to help their daughter learn the positive effects of organizing her time. The daughter had schoolwork that included texting and communicating with friends, but an hour before bed the phone was put away. That gave her a quitting time, and a set time to organize her next day.” From those changes, better sleep developed organically.
Poor Sleep Efficiency Has Poor Health Consequences
The importance of sleep efficiency isn’t just cognitive; it affects the whole person. A 2018 study from the American Academy of Pediatrics had some striking findings.
“We’ve seen substantial evidence showing the connection between poor sleep and obesity in teens,” Dr. Michael Breus, PhD, wrote about the study on his blog, The Sleep Doctor. “This new research goes further, giving us more detailed information about the risks to heart health and metabolic health that teens face if they don’t get enough high-quality sleep.”
This study followed 829 for ten hours per day over five days. The skinny was that longer sleep duration and higher sleep efficiency were associated with better cardiometabolic profiles, including lower blood pressure, smaller waist size, lower fat mass and insulin resistance. The results also indicated that girls were more likely to suffer from poor sleep efficiency (and thus worse health stats) than boys.
Tips for Improving Sleep Efficiency
Dr. Gruber is also the head of charity Children Sleeping Around the World. He offers some tips through the charity for better sleep hygiene good sleep habits.
- Go to bed at the same time every night
- Get up at the same time every morning
- Exercise early
- Relax before bed
- Stay cool
- Get in bed when tired and sleepy
- Get out of bed if unable to sleep for 20 minutes
- Avoiding caffeine and electronics (all screens) before bed is also a must.
Of course, it’s hard to force logic and well-meaning advice onto kids and teens. The Sleep Doctor Breus had this advice for parents: “Talk with your teens about the bigger picture—how the things they want to achieve in life are fueled by sleep. Even better, get a trusted adult who isn’t the parent—like a doctor or school counselor—to have that conversation.”
Mirell couldn’t agree more. “These are short conversations, not drilling into your child’s psyche. No negative comments – just listen. This ‘just listening’ helps your child organize their thoughts, gaining more sense of esteem and resilience.”
Sleep Efficiency: Sources
Hypersomnia Foundation
Science Direct / Sleep Medicine
McGill University Newsroom
Futurity
American Academy of Pediatrics study