Twenty minutes of real rest. Press start, close your eyes, and let your brain do the work it has been waiting to do.
Choose your nap length and press start
Within the first five minutes or so you transition from wakefulness into stage 1 sleep: your breathing slows, your muscles relax, and your mind begins to wander. By around ten minutes you are in stage 2, where sleep spindles fire in the brain and short-term memories get shuffled into storage. This is where the real restoration happens.
At 20 minutes your alarm fires. You are still close to the surface. The transition back is gentle. You open your eyes, you stretch, and within a minute or two you feel the benefit: sharper, calmer, and ready for the afternoon.
Go beyond 30 minutes and you risk tipping into slow-wave deep sleep. Waking from there is harder, and the grogginess can last the better part of an hour. The timer is not there to cut you short. It is there to keep the promise of a good afternoon.
If you have access to a cup of coffee, drink it just before you start the timer. Caffeine takes around 20 minutes to be absorbed. You will wake up at the moment it kicks in, which gives you a natural energy lift on top of the restorative effect of the nap itself. This is sometimes called a coffee nap, and the research behind it is genuinely encouraging.