The sleep cycle

To understand why we don't rest properly requires knowledge of the sleep cycle.

In this schema we can see reflected the five sleep phases. But the sleeping process is not a single cycle. Every time we complete one cycle another starts automatically. 


To enjoy a good rest, it must go through as many complete cycles without interruption.

For example. If we rest on a stand too firm, our movements are not free and our position can be forced. This will cause us to wake up without having completed the sleep cycle. 


Another example would be a noisy and poorly ventilated room. Both, the noise as a high temperature can break or make our rest not continuous, waking up constantly bothered by noise or heat.