Hormones and Your Body: 6 Surprising Effects

Age-by-Age Guide to Hormones

How your hormones change as you age:

This is the time of relative stability for your hormones, says Geoffrey Redmond, MD, an endocrinologist in New York City and author of It?s Your Hormones. Your menstrual cycle has likely hit its stride, with estrogen and progesterone rising and falling in predictable patterns, meaning that you can now anticipate your PMS (and soothe it before it blows up). What?s more, your body?s response to hormones is less dramatic now, which is why menstrual cramps may be less intense than they were during your teens.

For reasons experts don?t understand, your brain may become sensitive to your menstrual cycle's usual hormonal fluctuations, thus triggering more PMS symptoms. And for many women, this is the prime baby-making decade, which can equal a hormonal roller coaster. In fact, hormones can remain in flux for up to a year after childbirth, particularly if you breastfeed.

The upside: In your mid to late 30s, your body may have more available testosterone, which increases libido and sexual satisfaction, says Susan Rako, MD.

Although many women won't hit menopause until their 50s (the average age is 51), the long transition that a woman?s body makes as she moves toward it, known as perimenopause, can last four to five years. The result: Estrogen and progesterone levels can fluctuate wildly, triggering hot flashes, erratic periods, a fuzzy memory, fatigue, and moodiness.

"Half of women experience their first bout of depression during perimenopause," says Louann Brizendine, MD. On a more chipper note: Your levels of the bonding hormone oxytocin also decrease, which from a glass-half-full perspective is a good thing. Now that your body has dialed down your nurturing impulses, you may be better able to focus on your own needs.

Originally published in FITNESS magazine, July 2007.