SLEEPexpert is based on two fundamental processes of sleep regulation: sleep-wake behavior (homeostatic) and daily rhythm (circadian).
A sufficient period of wakefulness is necessary to build up enough sleep pressure to initiate and maintain sleep. This is supported by a circadian decline in the wake-promoting signal in the late evening (decreasing evening wake maintenance zone). Conversely, toward the end of the night and early morning, a circadian sleep-promoting signal helps maintain sleep (sleep maintenance phase). Healthy sleep results from the interaction of these two processes—sufficient sleep pressure and alignment with an appropriate circadian phase.