A MASSIVE NEW STUDY OF 20,000 ADULTS SAYS THIS IS WHAT HAPPENS WHEN YOU START GOING TO BED EARLY

We all get the same 24 hours. So why should it matter?

Forget the old adage that nothing good happens after midnight. I’ve had an awful lot of fun in the early morning hours.

It wasn’t just going out and partying in my younger years, either.

In fact, I’ve written before about the almost magical experience I once had when I put on an old army t-shirt with a big “USA” on the front for a middle-of-the-night run:

Total insomnia so I went for a run at 4:45 a.m. (75F-perfect!) It’s amazing who’s out in DC at that time.

My favorite encounter was two girls apparently still wrapping up last night’s party at the Washington Monument. One of them pointed to my USA t-shirt and the 56 US flags surrounding the monument and exclaimed with apparent sincerity, “Don’t you just… LOVE America?!!”

Like so much in life, however, there’s a time for that, and a time for other things.

Now, a big new study published in Proceedings of the National Academy of Sciences (PNAS) suggests that, for adults anyway, there’s a lot to be gained by going to bed early.

Researchers analyzed the sleep and exercise habits of 19,963 adults who agreed to wear wrist-borne biomedical devices to track their activity. The data amounted to a whopping 5,995,080 “person-nights,” and allowed them to figure out if habitually early bedtimes correlated with other habits.

Sure enough, they found a big one: The earlier people went to bed, the more likely they were to engage in moderate-to-vigorous physical activity the following day.

Adults who habitually were in bed by 9 p.m. got about 30 more minutes of physical activity in the following day than those who went to bed at 1 a.m.

The 9-o’clockers also outdid adults who went to bed habitually at 11 p.m., getting about 15 more minutes of physical activity in than their more night owl-ish peers.

This strikes me as one of those correlations that makes sense intuitively, but also seems surprising when we have hard data to back it up.

I mean: We all get the same 24 hours in any day, right? So why should it matter if some of us shift our sleeping hours later than others?

Is there something intrinsic that suggests that if you stay up until after midnight, you wouldn’t be squeezing in a workout at 4 p.m.?

Maybe so. The researchers said they also determined that if people who normally went to bed late made a conscious shift to earlier bedtimes, their physical activity increased.

In other words, it’s not likely true that people who stay up late are also preternaturally disinclined to exercise. Instead, it seems more likely that as a society, our schedules just lend themselves better to working out if we get to sleep earlier.

One thing we have to mention, although I’m sure you already know this: Exercise is associated with almost every positive health outcome we can come up with.

Perhaps my favorite example comes from a 2017 study that suggests that people who engage in high levels of physical activity (defined as “engaging in 30 minutes of jogging for women, or 40 minutes of jogging for men … five days per week”) wound up with health benefits that amount to a “biologic aging advantage of nine years.”

“These insights carry meaningful implications for public health,” said lead author on the more recent study, Dr. Josh Leota of the School of Psychological Sciences at Monash University in Australia. “Rather than just promoting sleep and physical activity independently, health campaigns could encourage earlier bedtimes to naturally foster more active lifestyles. A holistic approach that recognises how these two essential behaviours interact may lead to better outcomes for individual and community health.”

I’d love to know what times of day the people in the study who went to bed earlier exercised. Was it as simple as being able to get up early in the morning and get their activity in then?

Or were they starting their workdays earlier, getting out earlier, and then hitting the gym (or whatever it was they did)?

Either way, it’s good research to know about, especially for busy leaders who find themselves trying to fit work, family, friends, fitness, and sleep into their schedule.

Otherwise? As my Inc.com colleague Jessica Stillman once wrote, quoting Randi Zuckerberg, you can be left with a difficult choice: “Pick three.”

Good luck sleeping on that one.

This post originally appeared at inc.com.

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2025-07-21T12:35:07Z