We all know a quick nap can be very refreshing…but how long is too long?

Sleep experts tell CNBC the sweet spot is 20 to 30 minutes.

If you nap any longer than that, you start getting into deeper stages of sleep and can wake up feeling groggy.

Just 20 to 30 minutes is enough to give you a boost in energy, help you focus and improve your mood.

They suggest setting an alarm for 30 minutes which gives you five to ten minutes to fall asleep and 20 minutes of actually sleep time.

Oh…and don’t do it too late in the day.

Try not to nap less than eight or nine hours before your normal bedtime which for most people is no later than 2pm!

Sweet (quick) dreams!