Your heart. Your biggest risk after you pass menopause is not breast cancer but heart disease. It's the leading cause of death in women over 45. Unfortunately, not enough women realize this. So if you haven't already, now is the time to really start paying attention to things like cholesterol levels, weight, physical activity and diet.

Why now? Well, until now high levels of estrogen protected your heart, one reason women develop heart disease an average of 10 years later than men. However, as estrogen levels decline, so does that protection. While it's still not clear if supplemental estrogen can continue that protection, that's almost beside the point. If you're eating a heart-healthy diet composed of healthy fats, lots of fruits, vegetables and fiber, and low-fat protein like fish and soy, accompanied by at least 30 minutes of physical activity a day, you're well on your way to providing your body with what it needs to replace the previous protection of estrogen.