At one time sleep was considered just the time you were not awake as a single entity, but now we know that sleep has several different stages where different processes occur. During sleep there is quite a bit of brain activity and many functions are performed that are essential to our health and well-being.
Analysis
Because of this, insufficient sleep can be unhealthy and even dangerous. One of the first systems affected by lack of sleep is the immune system. Too little sleep damages immune function and makes ...