Do you need more sleep after a hard workout?

You turn in earlier when you've lined up a big workout for the following day, but what about the other side of the clock? Once you've hit your foam roller and refueled with the necessary nutrients, do athletes actually need to sleep more post-hard workout? “The simple answer is absolutely,” says W. Christopher Winter, M.D., and director of the Martha Jefferson Sleep Medicine Center in Charlottesville, Virginia.

For the most part, everyone needs about 7 hours of sleep in a 24-hour window.

But “if you’re active—either physically or mentally—your body creates more adenosine, a chemical that works to create sleepiness, and you’ll accrue more of a drive to sleep,” Winter says. Consider ATP, the energy current of your body. Our bodies create it and break it down to give us energy. “A runner is burning a lot of ATP and using that for energy,” Winter says. And a byproduct of that ATP? Adenosine.

But does more of an urge to sleep mean more of a need to sleep? In many ways, yes. “There are mechanisms within sleep that help clear adenosine from our brain,” Winter says. So when you get enough sleep, you’ll wake up refreshed. If you don’t, you may wake up groggy, with adenosine still circulating.

And more sleep has its athletic perks. One study found that when tennis players upped their shuteye to 10 hours a night, they sprinted faster and improved the accuracy of their hits. On the other hand, research has demonstrated that regular exercise—at least 150 minutes a week—can improve sleep quality and energy levels throughout the day.

Of course, fitness levels do matter when it comes to how much exercise will leave you exhausted. Take two twins, one who’s a runner and one who’s not. The non-runner will likely have a much different response to a long, hard jog. “If you’re breaking down more ATP and have a stronger stress response, you’ll probably be a lot sleepier,” says Winter.

To build in ample bedtime: Think about post-workout zzz’s like you think about post-workout food, suggests Winter. “If you’re really active, you’re going to be hungrier than if you’re sitting around all day," he says. "But while intense exercise is likely to increase your sleep need over time, the exact amount is unclear. It depends on the athlete." You know your body best—if after a hard workout day, you tend to wake up feeling groggier than normal, you probably need to nix the pre-bed Netflix and prioritize that extra hour of sleep instead.