The video above, from ASAP Science, explains how power naps take advantage of the first two phases of your sleep cycle: stage one, where you’re probably dozing; and stage two, where your brain starts to consolidate memories, organise its biological bookshelves and shuts the brain off from external, non-dangerous stimuli.
The trouble comes in stage three — the part where you’re in deep sleep and difficult to wake. That’s when you start to feel groggy. If you hate mornings, you’re probably waking up during this phase. So the key to getting all of the benefits of naps without the drawbacks is to sleep for only 30 minutes or so, which is the time it takes your brain to go through the first two stages.
We’ve discussed this idea before, and even noted that timing is important when you nap. For more on this topic, hit the YouTube link below and check out some of the published studies in the video description.