All forms of sleep control with an alarm clock will increase the overall demand for sleep. This means that:
If you use an alarm clock, either:
- you will sleep longer, or
- you will feel more miserable.
Artificial sleep schedules will dramatically reduce your mental capacity. A healthy individual in normal conditions will find it difficult to fall asleep 4 hours after the main sleep episode unless that episode was unnaturally cut with an alarm clock resulting in sleep deprivation.