When you sleep at night, your body goes through a series of sleep cycles. The average adult completes 4-5 full sleep cycles over 8 hours. Each cycle lasts about 90-110 minutes and includes five distinct stages, as illustrated in the sleep diagramme.

Every person has his or her own individual sleep cycle, and every cycle is distinctly different from every other cycle. These sleep cycles can be altered by diet, sport or exercise, medication, alcohol, drugs, sleep disturbances and sleep deprivation.

1. During Stage 1 of your sleep cycle, your sleep is light.
2. In Stage 2 your sleep gradually deepens.
3. In Stages 3 and 4, also called the DELTA phase, your sleep is deepest. During these stages, your body reviews the stresses of the day.
4. Stage 5 of sleep, also called the REM phase, is characterised by notable physiological changes such as accelerated breathing, increased brain activity, rapid eye moment and muscle relaxation.  It is during this phase that you dream.

In the first part of the night, the Delta phases last longer than the REM phases. As the night goes on, DELTA phases become shorter. In the final part of the night, the Delta phases disappear and the REM phases last longer. At certain times in the long REM phases, the person asleep is already ALMOST AWAKE.

Sleeptracker® registers these "almost-awake" moments and initiates an alarm as soon as the first such moment occurs within a pre-selected wake-up time window. The result: You wake up feeling refreshed and full of energy, even if you have had very little sleep.

Please note: The data provided are not sufficient for the analysis and treatment of sleep disturbances. For analysis and treatment of sleep disturbances, consult a doctor.