This article originally appeared in the March 2016 issue of SELF.
But if working out first thing doesn't jibe with your schedule, all is not lost. In fact, nighttime sweat sessions have so much upside that even early risers might consider including them in their weekly lineup of workouts. If you're wondering, 6 P.M. is actually the most popular time of day for running, strength training, indoor cycling and dance-cardio workouts, according to Jawbone stats.
Here, three of the benefits of working out at night:
1. You'll work out harder.
Research has shown we can go up to 20 percent longer in the evenings, and at a higher intensity. Performance peaks 11 hours after waking for late risers, per a new study from England's University of Birmingham. (Even early birds fare better later: They did best aerobically about six hours after waking.) And when you can go harder, longer, faster, stronger, you'll see the payoff quicker.
2. You'll tone up faster.
Muscle function and strength peak in the P.M., according to research, and fluctuating hormones may make late- day workouts more effective. High levels of cortisol in the morning can prevent muscle growth, but increased testosterone in the evening boosts it, says Heather Webb, a kinesiologist at Texas A&M University in Corpus Christi.
3. And you'll sleep more deeply.
Late workouts disrupt sleep, right? Nope. When hitting the sack 90 minutes post-exercise, people who'd gone harder got more deep, restorative sleep, found Swiss researchers. Also, in a study in Sleep Medicine, only two percent of vigorous exercisers said workouts interrupted their zzz's; 30 percent slept better after a good sweat. And you've heard it before, logging quality sleep is imperative to muscle recovery and seeing fitness gains.
If there were any question about the strength of nighttime workouts, it's been put to rest.