For many people, working out is a great way to increase energy and feel great. But after a rough night of sleep, it’s tempting to skip the gym. On one hand, we know consistency is crucial for progress in the gym, but on the other hand ... there’s nothing quite like getting sufficient sleep. Not to mention that anyone who’s ever tried to physically push their limits after tossing and turning can probably tell you that things are significantly less productive when your eyelids are drooping.

It turns out there’s research to support the right approach after a bad night’s sleep. Sleep scientists decided to investigate the matter last year, exploring what kind of impact sleep loss (defined as fewer than the recommended seven to nine hours at night) could have on physical performance. In a meta-analysis of 69 existing studies, researchers looked at the influence of sleep loss on all kinds of next-day outcome measures like power, speed, strength and endurance. What they found wasn’t exactly surprising: Sleep loss does appear to have a negative impact on performance.

There is, however, an interesting additional tidbit to note: While sleep loss consistently derailed efforts when exercise was performed the next afternoon or evening, it didn’t seem to negatively impact morning performance.

So, if someone didn’t sleep well the night before, is it better to work out in the morning, or should the person rest up instead?

“Sleep loss has a negative effect on exercise performance—namely sleep deprivation (i.e., not enough total sleep time) and going to sleep too late,” explains neurologist and sleep medicine specialist Dr. Raina Gupta of Sleepologie Health and Wellness. “[According to the study], if people are unable to sleep enough for whatever reason, they should try to exercise in the morning as later in the day they may feel more fatigued, which means less speed, strength, power, skill and endurance (i.e. worse workout performance).”

Dr. Chris Winter, neurologist, Mattress Firm advisor and author of “The Rested Child” and “The Sleep Solution,” says gym-goers of all levels should be aware that the fewer hours they sleep, the more that acute sleep loss will worsen their athletic performance. “These authors chose an arbitrary cutoff of six hours, but it's probably better to think of it as a continuum—like temperature,” he says. “The more the temperature drops or rises from 69 degrees (Fahrenheit), the less likely someone is to feel comfortable.” So, the further away an individual moves from that optimal sweet spot for amount of sleep, the more they can expect their workout to suffer.

While the meta-analysis reinforces some known facts about sleep loss and its impact on athletic aptitude, it’s not anything new.

Better sleep now should also result in better results long term. “We know that low total sleep time or sleep deprivation makes us have many negative effects, and that increasing or optimizing our total sleep time can have many positive effects,” Gupta explains. “Many of us have experienced running out of steam at the end of the day, and therefore our exercise performance will also decrease—more so when we haven't slept enough. This is a reminder that everyone can benefit from better sleep, including professional or non-professional athletes or even the average adult who enjoys a workout in the afternoon or evening.”

Ultimately, Winter has a definitive reply to the question of whether to work out in the morning or catch up on sleep: Get the sleep. He adds that he’d rewrite the final findings of the study to clarify the results. While the researchers write that individuals should “prioritize exercise to the morning in an effort to maintain performance,” Winter says that’s not actually the point they’re trying to make. “They are not saying to exercise in the morning to improve performance—especially in the face of sleep loss,” he explains. “What they are trying to say is that if you value performance, prioritize getting enough sleep so you can work out refreshed in the morning.”

How to Fit Exercise Into a Day of Short Sleep

If you opt to catch up on sleep, but would still like to have a level of activity in your day, try scaling it back a bit. “Many people benefit from being active for a short time later in the day to promote wakefulness—like going for a 5- to 10-minute walk or walking up or down the stairs for a few minutes to wake up,” Gupta says. In addition, she recommends any of the following activities for a quick energy boost:

• Taking a break
• Eating a snack
• Listening to music
• Breathing deeply for one minute
• Taking a power nap (less than 20 minutes)
• Talking to a friend or colleague

“These can all be helpful in giving us energy to get through the day,” Gupta says.

But the best thing you can do, according to Winter, is not overthink things. “My advice would be to relax,” he says. “I'm guessing there are studies that show ‘food loss’ affects performance in the gym ... yet we are going to skip lunch occasionally. Studies like this (and their resultant media response) tend to create panic more than anything else. It's okay to go to the gym after a difficult night; in fact, it might be a good idea in some cases to keep that routine going. This prevents an isolated bad night from becoming the norm. If a late flight or work deadline truly subtracts from your sleep time, skip the gym. Rest first; the squat rack isn't going anywhere.”