Effects of Aging on the Endocrine System

The endocrine system consists of a group of glands and organs that regulate and control various body functions by producing and secreting hormones. Hormones are chemical substances that affect the activity of another part of the body. In essence, hormones serve as messengers, controlling and coordinating activities throughout the body. (See also Endocrine Glands Endocrine Glands The endocrine system consists of a group of glands and organs that regulate and control various body functions by producing and secreting hormones. Hormones are chemical substances that affect... read more .)

Levels of most hormones Endocrine Function The main function of endocrine glands is to secrete hormones directly into the bloodstream. Hormones are chemical substances that affect the activity of another part of the body (target site)... read more decrease with aging, but some hormones remain at levels typical of those in younger adults, and some even increase. Even when hormone levels do not decline, endocrine function Endocrine Function The main function of endocrine glands is to secrete hormones directly into the bloodstream. Hormones are chemical substances that affect the activity of another part of the body (target site)... read more generally declines with age because hormone receptors become less sensitive.

Some hormones that decrease with aging include

In women, estrogen levels decline with menopause Menopause Menopause is the permanent end of menstrual periods and thus of fertility. For up to several years before and just after menopause, estrogen levels fluctuate widely, periods become irregular... read more . In men, testosterone levels usually decrease gradually. Decreased levels of growth hormone may lead to decreased muscle mass and strength. Decreased melatonin levels may play an important role in the loss of normal sleep-wake cycles (circadian rhythms) with aging.

Hormones that usually remain unchanged or only slightly decrease include

Hormones that may increase include

Some age-related hormonal changes may impact quality of life or cause bothersome symptoms (eg, hot flashes). Estrogen and progesterone therapy in menopausal women is discussed in Menopause Menopause Menopause is the permanent end of menstrual periods and thus of fertility. For up to several years before and just after menopause, estrogen levels fluctuate widely, periods become irregular... read more . Testosterone replacement in older men is discussed in Effects of Aging on the Male Reproductive System Effects of Aging on the Male Reproductive System It is not clear whether aging itself or the disorders associated with aging cause the gradual changes that occur in men's sexual functioning. The frequency, duration, and rigidity of erections... read more .