5 Ways Your Body Changes After 39 That No One Talks About

What you know: You might feel a little foggy and notice that you're having trouble remembering everything on your to-do list. And that actress who was in that show with whatshisface? Her name isn't even close to the tip of your tongue.

What might surprise you: This is not just because of the normal aging process–it's part of the normal female aging process. "We have estrogen receptors in two brain areas that control memory, and when there's less estrogen, there are structural changes in those areas," explains Pauline Maki, PhD, a professor of psychiatry and psychology and the director of the women's mental health research program at the University of Illinois at Chicago, and president of the North American Menopause Society. The first area is the hippocampus, considered the memory center of the brain, and the second is the prefrontal cortex, "which organizes information in meaningful ways so we can remember it better," says Maki. Estrogen also boosts levels of acetylcholine, a neurotransmitter that helps us form new memories.

What you can do about it: The good news, though, is that your forgetfulness isn't permanent. "The brain bounces back after menopause," says Maki. "It adapts to lower estrogen levels, and it compensates." You might be wondering about skipping the whole forgetfulness phase with estrogen therapy. It does seem to help, as women placed in brain scanners during memory tasks showed more activity in the hippocampus when they were put on the therapy, says Maki. But she notes that memory issues alone aren't a convincing reason to go on hormone therapy, as it comes with serious risks, like increased chances of breast cancer, heart disease and stroke.