Hormones are the body’s chemical messengers. They act on various tissues and organs in the body to change their behavior. For example, the hormone prolactin stimulates the production of breastmilk.

Thyroid hormones play a fundamental role in cardiovascular function. They influence how the heart responds to adrenaline, how the heart uses energy and how constricted or relaxed blood vessels are.

Sleep and hormones affect each other through your circadian rhythm, also called the sleep-wake cycle. A lack of sleep can affect several hormones at once. Getting 7 to 9 hours of sleep helps regulate ...