Buy backpacks, exercise machines, athletic shoes, and more at Fogdog Sports. There are a lot of good reasons, especially if you're a woman.
Weight training can help prevent that loss, or even reverse it.
It also has more immediate benefits. Lifting weights can improve your balance and range of movement, help prevent exercise-related injuries, and help you lose weight and keep it off. After the first several months of training, you can also expect to see a 20 to 40 percent increase in your muscle strength, which translates into a lot less huffing and puffing when you carry the groceries, mow the lawn, or play sports. A good routine takes about 30 minutes, working all your muscle groups for a few minutes apiece. Do a few light stretches as well.