Sleep As the years pass, many find it harder to get to sleep and to stay that way. And it matters, because getting enough sleep is as vital as healthy eating and getting exercise. Not sleeping enough can increase your appetite – and thus your waistline, damage your health – including causing pre-diabetes, impair your immune function – more colds, make you irritable, lessen your ability to concentrate and think clearly, and reduce your ability to interact socially. More than that, lack of sleep can also speed up the aging process.