Does water aerobics have any effect, positive or negative, on bone density? I'm 43 and have osteoporosis of hip, osteopenia of spine. Some have even speculated that my osteoporosis may be the product of my early years when I was a competitive swimmer, and swimming was my ONLY exercise.

First you need to understand that your early years of competitive swimming did not harm your bones. On the contrary, if you were well nourished when you were younger, any exercise you did would *help* your bones. You are right that swimming now will not help you reverse bone loss. Water aerobics may offer a slightly better benefit for bone than swimming. But even though you're upright, the water still supports most of your body weight. So the forces applied to bone during water aerobics are not strong enough to have a positive impact. This doesn't mean you should skip water aerobics - there are lots of other benefits, including fun! But for the sake of your bones, make room in your schedule for other physical activity too.

To reverse bone loss you need to do weight bearing exercises (like brisk walking), in combination with strength training. Because you're at risk for fractures, discuss exercise with your doctor before you start. I hope you're also getting plenty of calcium, as well as vitamin D. Because you're young - and your bones need to last for many years - please talk to your doctor about medication, which also can be helpful to you. A combination of therapies is by far is the most effective way to improve and maintain your bone health, so you don't experience fractures as you get older.