You're Exhausted: Should You Sleep More Or Exercise?

It's late and you're tired. Maybe you're watching a show, reading a book, getting home late, or awake for another reason.

Whatever it is, you know you shouldn't be up this late, especially because you have a workout planned in the morning.

All of a sudden it's morning. Your alarm is blaring, the sun is rising, and it feels like there's no way you could possibly work out right now.

You hardly slept, after all, and even though you tell yourself you should exercise, your body is craving more shut-eye.

Which do you choose? The extra rest or endorphin rush? More importantly, which should you choose?

We asked clinical psychologist and sleep specialist Michael Breus, Ph.D., aka the Sleep Doctor, whether he recommends snoozing or sweating.

"There are several areas where lack of both quality and quantity of sleep can affect your performance," Breus says. "These aspects are quantifiable."

Below, Breus breaks down what not getting enough sleep may mean for your workouts.

"Reduced energy via lack of sleep (specifically stages 3 and 4) decreases glycogen storage," Breus told mbg. "Without fuel in the tank, you're running on reserves."

If you've ever played a sport, lifted weights, or run on a treadmill, you know that impaired attention just isn't going to cut it—and if you are sleep-deprived, that's exactly what you'll get. "Performance measures of predictive visual tracking accurately reflect impaired attention due to acute sleep deprivation," he says.

Breus also notes that hand-eye coordination has been directly linked to sleep deprivation—when you sleep less, your coordination suffers. Again, not what we want when we're exercising.

"Studies show that sleep-deprived individuals will know the risks of their decisions but not care what those risks are, and take risks unnecessarily," Breus says.

If you've ever spoken to an athlete or trainer, you know how important recovery is after a workout. Well, not getting enough sleep can interrupt and impair that process.

As Breus puts it, "Sleep deprivation, sleep disturbance, and circadian rhythm disturbance all affect the overall restorative and recovery aspects of sleep."

Believe it or not, Breus says that sleep can also affect how we perceive pain. Namely, sleep deprivation can make pain, well, more painful.

Too many of our psychological and physical processes and abilities are impaired when we're sleep-deprived—exercising won't improve that, and this lack of proper functioning can put our bodies at risk.

"If you are sleep-deprived," Breus says, "you have the likelihood of several things:

So the next time you're wondering whether you should hit the gym or hit the sheets, first consider the consequences, and then try to get more sleep the next night. In the meantime, hit snooze. It's only one workout.