Dr. Jeffrey Iliff is answering your questions about sleep. He’s a researcher at the University of Washington School of Medicine and is an expert in his field. Have you ever wondered how long the perfect nap should be? Or if you can catch up on sleep? He’s your sleep sensei here as he’s answering some popular questions from Twitter. By the way, there’s good naps and bad naps. If you nap, you should do a short 20-30 minutes or 90 minutes for one more sleep cycle. If you nap too long your body thinks it’s time to go full on night night mode and when you wake up you’ll be more tired. So keep the nappys shorter if you can, or exactly one sleep cycle.