Some of us feel well-rested after a solid eight hours of sleep. For others, closer to nine feels best. For others still, a little less will do. How much sleep we prefer to get is highly subjective -- but how much sleep we need is a bit more concrete.
After web analytics showed the vast popularity of the How Much Sleep Do We Really Need? feature of the National Sleep Foundation's (NSF) website, a panel of experts set about to reassure that the information provided there was the most accurate and up to date.
"Sleep duration was basically one of the most visited pages on the NSF website, and it wasn't really clear how those recommendations for the ranges had been arrived at," Max Hirshkowitz, Ph.D., chair of the National Sleep Foundation Scientific Advisory Council, told The Huffington Post.
To do so, a panel of six sleep experts and 12 other medical experts from organizations including the American Academy of Pediatrics, the American Geriatrics Society, the American Psychiatric Association and the Society for Research in Human Development, conducted a formal literature review. The panel focused on the body of research surrounding sleep duration in healthy human subjects that had been published in peer-reviewed journals between 2004 and 2014. From the 312 articles reviewed, the experts were able to fine-tune existing sleep duration recommendations as detailed below:
- Newborns (0-3 months): 14-17 hours (range narrowed from 12-18)
- Infants (4-11 months): 12-15 hours (range widened from 14-15)
- Toddlers (1-2 years): 11-14 hours (range widened from 12-14)
- Preschoolers (3-5): 10-13 hours (range widened from 11-13)
- School-Age Children (6-13): 9-11 hours (range widened from 10-11)
- Teenagers (14-17): 8-10 hours (range widened from 8.5-9.5)
- Young Adults (18-25): 7-9 hours (new age category)
- Adults (26-64): 7-9 hours (no change)
- Older Adults (65+): 7-8 hours (new age category)
(In addition, the NSF has also added categories for the outliers among us, supplying the range of hours of sleep that have been deemed both “May be appropriate” and “Not recommended.”)
“This is the first time that any professional organization has developed age-specific recommended sleep durations based on a rigorous, systematic review of the world scientific literature relating sleep duration to health, performance and safety,” Charles A. Czeisler, Ph.D., M.D., professor of sleep medicine at Harvard Medical School and chairman of the board of the National Sleep Foundation, said in a statement.
It's not an exact science, said Hirshkowitz, but it's a start. "Like with most things, it's successive approximation that gets you to the goal. The first time somebody built a wristwatch, it wasn't very good, but after hundreds of years of making precise changes, to have a timepiece that doesn't tell time is pretty unusual." As more and more research is conducted around sleep duration, subsequent minor changes will be made, he said, helping experts to zero in on the absolute best recommendations to give to patients.
If you're currently getting enough sleep and feel pretty good, keep it up. But if you're meeting your age group's recommended range and waking up groggy and feeling slugging throughout the day, it could be a warning sign of various sleep conditions or a less-than-ideal sleep environment, said Hirshkowitz, which you might want to address with a healthcare professional.
If you're simply not sure, he suggests doing a little home experiment. Start with the midpoint of the sleep duration range for your age group. Note you how feel when you wake up, how you feel during the day and how you feel as you're winding down in the evening. Then, depending on how you feel, you can adjust your time in bed to be shorter or longer as you see fit.
Or, try something a little less elaborate. "If you could select your bedtime and wake time, what would it be?" Hirshkowitz asked. I said 11:30 p.m. and 8 a.m. "Now, if that is going to be your set bedtime forever, forevermore, you will never be able to get one extra minute, you will always have exactly that amount of sleep -- do you want to adjust what you said?" Never one extra minute?! I gave myself an extra hour -- and most people adjust when faced with this exercise, he said. Your optimal sleep duration is probably somewhere in between those two ranges.