Not everyone has time for a daily nap, but when the opportunity arises, what’s the ideal time to snooze? A new nationwide survey set out to find the answer.

Commissioned by Avocado Green Mattress, and conducted by Talker Research, the survey pinpointed the perfect “nap o’clock” is at 1:42 p.m.

“Brief naps can improve working memory resources,” said Philip Gable, a professor of psychological and brain sciences at the University of Delaware. “It can have a benefit to mood improvement.”

The survey found that the ideal nap length is 51 minutes.

However, respondents warned that if a nap extends 35 minutes beyond that, it enters a “danger zone” where the nap may do more harm than good, leaving the person sleeping feeling groggy.

If it stretches one hour and 44 minutes beyond the ideal nap length, it’s no longer considered a nap at all. In that case, it’s officially a full sleep session, according to the survey.

“A longer nap is going to put you on different sleep cycles, and it’s more likely to mess with your circadian rhythm,” Gable explained.

“I would say there’s no substitute for a good night’s sleep, so even if you plan on taking a nap, it’s still not going to benefit you as much as getting a really good night’s sleep.”

Respondents did find benefits from taking a midday snooze, with 55% saying they immediately feel a boost of productivity after waking up from a nap.

“I think one of the great things about sleep is that it helps us process things a little bit better,” Gable said. “When we’re sleep-deprived, we react a little bit more emotionally to things versus when we have all of our faculties in play.”

“When we’re well rested, we have a better ability to see the bigger picture,” he added.

The survey polled 2,000 Americans between Jan. 23-27 with a margin of error of plus or minus 2.2 percentage points.