You know that moment in the evening when you suddenly get so tired that it gets hard to keep your eyes open? In this state, falling asleep happens almost automatically. You might also have noticed that if you resist the feeling and don't go to sleep, the tiredness eventually fades away. After that point falling asleep can get much more challenging. This is a sign that you have just passed your natural bedtime window.
Two processes regulate your sleep-wake rhythm: the circadian clock and sleep pressure. Together they create a time frame, called the bedtime window, inside which it is the easiest for you to fall asleep. Reaching your bedtime window means that you have accumulated just the right amount of sleep pressure for your nightly rest. It is easy to notice this window for some people, while for others, it's harder to spot. Your circadian clock also affects the timing of the bedtime window, which is why it stays relatively same from night to night. This is one of the reasons why you should aim to keep your bedtime consistent and day rhythm in check.
When you use Nyxo to track your sleep, we automatically calculate your optimal bedtime window, which you find in the diary view. Missing your optimal bedtime window might temporarily make you feel less tired and increase the time it takes for you to fall asleep when you finally go to bed.
Habits From This Lesson
Partonen, T. (2014). Lisää unta – Kiireen lyhyt historia. Helsinki: Duodecim.
Walker, M. (2017). Why we sleep: Unlocking the power of sleep and dreams. Simon and Schuster.