ATLANTA, GA — According to a survey conducted by Talk Research and commissioned by Avocado Green Mattress, the best time to take a nap is 1:42 in the afternoon and it matters for how long, too.

Researchers have found the ideal amount of shut-eye for that afternoon nap is 51 minutes.

If it’s much longer, you may find yourself feeling worse than before the nap.

“As a psychologist, I see firsthand how sleep — especially napping — affects mood, focus and overall well-being. So many people nap the wrong way and then wonder why they feel groggy instead of refreshed,” says Nick Bach, who holds a doctorate in psychology, in a statement.

Bach warns, “I always tell people that if they nap too long, they risk entering deep sleep, which makes waking up harder. A quick 20 minute nap is perfect for a recharge.”