Solving The 8 Hour Debate: How Much Sleep Do We Really Need?

With daylight savings a little over a month away, school routines back in place and business ramping up, fall tends to be a time to buckle down and solidify a consistent schedule. At the same time, back to school and longer hours at work can often translate into less sleep for many—while pressure to perform in both venues demands more rest. One hotly debated aspect of sleep hygiene is the amount of shut-eye to aim for each night in order to be productive during the day. While the full eight hours have long been encouraged, there are new arguments for more sleep and others for less. We explored them to get to the bottom of the eight-hour debate.

According to sleep scientist, Daniel Gartenberg, there’s a new optimum amount of sleep in town: 8.5 hours. The TED talking researcher and entrepreneur has other thoughts on the correlation between sleep and work too. In a recent Quartz interview, Gartenberg championed the idea of sleep as a worker’s right, explaining that, “People should be able to sleep like they’re able to get healthcare. This also means making our work environments more conducive to sleep. For optimum productivity, we need around eight hours of sleep, right? But that doesn’t have to be in one go. Maybe I’ll get a little less than that during the night, and then I’ll take a 20-to-30-minute power nap at midday.” We’d take a guess that Gartenberg is on board with nap pods.

He also talked more explicitly about the sleep amount debate by saying that, “In order to get a healthy eight hours of sleep, which is the amount that many people need, you need to be in bed for 8.5 hours. The standard in the literature is that healthy sleepers spend more than 90% of the time in bed asleep, so if you’re in bed for eight hours, a healthy sleeper might actually sleep for only about 7.2 hours.” So his theory isn’t necessarily that 8.5 hours sleeping is better, but building in time to fall asleep can help people achieve a fuller amount.

To this point, a recent CNBC article shared that researchers analyzed data from Fitbit and “found that people who slept an average of 5 hours and 50 minutes to 6 hours and 30 minutes per night performed better on the test than people who slept more or less.”

Although these numbers are lower than what is typically advised, the article goes on to say that, “Fitbit research scientist Jonathan Charlesworth said these guidelines are based on how much time people spend in bed as opposed to how much time people actually sleep. However, he said even Fitbit's numbers are just averages, and the numbers can vary per person, especially based on factors like age and gender.”

Other sleep experts take a more cavalier approach, focusing less on how many hours of sleep people ideally need and more on how much sleep will prevent health issues like emotional instability, detriments to metabolism and more. Additionally, they are exploring the amount of sleep you need to accomplish day to day tasks, arguing that as people age they can (and must) function with somewhat less sleep.

In this recent Time article, several sleep experts discussed sleep at different ages and the resulting changes in ability and needs. “It’s pretty clear that sleep ability decreases with age,” says Michael Grandner, director of the Sleep and Health Research Center at the University of Arizona College of Medicine.  Another sleep expert in the article talked about how people use their sleep, “When people ask me how much sleep they need, I ask them, need for what?” says Max Hirshkowitz, a professor emeritus at Baylor College of Medicine and former chairman of the National Sleep Foundation. “Do you need sleep to do complex math or drive a truck for 14 hours, or do you need it to watch TV?” This is an interesting question since we are generally so focused on determining a precise but also universal number, and rarely think about sleep like a currency – a certain quantity needed for some activities, more or less needed for others.

While experts featured in this article overall agree that babies, children and teens need more sleep than adults, they also emphasize that middle-aged to elderly individuals may struggle more to get adequate sleep and that might be ok. “We say, on average, try to get seven or eight, but inevitably you’ll have people who need more or less than that,” Grandner says. Ultimately Grandner posits, that while we should aim for a target 7-9-ish hours, this is unrealistic and it’s ok to have a 6-hour night here and there.


All of this in mind, the National Sleep Foundation offered updates to the suggested amounts of sleep per age group in 2015:

National Sleep Foundation

  • Newborns (0-3 months): 14-17 hours each day (previously it was 12-18)
  • Infants (4-11 months): 12-15 hours (previously it was 14-15)
  • Toddlers (1-2 years): 11-14 hours (previously it was 12-14)
  • Preschoolers (3-5): 10-13 hours (previously it was 11-13)
  • School age children (6-13): 9-11 hours (previously it was 10-11)
  • Teenagers (14-17): 8-10 hours (previously it was 8.5-9.5)
  • Younger adults (18-25): Sleep range is 7-9 hours (new age category)
  • Adults (26-64): 7-9 hours
  • Older adults (65+): Sleep range is 7-8 hours (new age category)

Overall, the consensus among all these hypotheses is it is crucial to form regular sleep habits, and that no matter how busy life gets, sleep must remain a priority for overall positive health. While 30 minutes here and there may not make the biggest difference, giving ourselves more time settle in and fall sleep could help us get a larger quantity and better-quality rest overall. That said, this debate will probably continue to go on as individual needs vary. One specific recommendation is unlikely to work for everyone – though we can confidently say that you really do need sleep to be healthy.

Read more here, here, here, here and here.


This article originally appeared in Sleep Retailer eNews on September 27, 2018

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