Medical Today

The quantity and quality of sleep is important for normal immune function; inadequate sleep increases the risk of colds and flu.

Researchers from Carnegie Melon University found that healthy adult men and women who slept less than 7 hours per night increased the risk of catching a cold by nearly 300 percent. Poor sleep efficiency (percentage of time in bed actually sleeping) increases the risk by 550 percent. Sleep habits were assessed in 153 healthy adult men and women for two weeks. They were then quarantined and given nasal drops containing a cold virus. People who slept longer and more efficiently were more resistant to colds.

Definition
Depression, also known as depressive disorders or unipolar depression, is a mental illness characterized by a profound and persistent feeling of sadness or despair and/or a loss of interest in things that once were pleasurable. Disturbance in sleep, appetite, and mental processes are a common accompaniment.