What to Do: If you can, join a gym or a fitness class. Depending on your budget and your life circumstances, you may choose any number of options, from boot camp-style workouts to belly dancing to mom-and-child yoga. These classes promote fitness and social interaction, which is important at this stage of your life. This is also a great time to join a diet club, whether it's a national network like weight-watchers or a local support system of friends with a shared goal.

Your 50's

Pros: Many women find their 50's are a great time to start fresh, whether it's a new career or hobby, new relationship, or new workout program. This age used to mean "old" but now it means you're ready to tackle the next exciting phase of your life.

Cons: Reduced flexibility, muscle strength, and endurance. The majority of women also go through menopause in their 50's, which can bring on a host of unfriendly side effects, including weight gain.

What to Do: Continue your fitness routines, as your health allows. If you haven't paid enough attention to working out throughout your life, it's not too late to start. There are lots of fitness programs specifically designed for women 50 and over. Adding methods like yoga and Pilates can help maintain flexibility and balance.

Your 60's and Beyond

Pros: If you're active at this age, you have a good chance of staying strong and healthy well into old age. You know your body well, and are learning to adapt to and cope with its changes.

Cons: The usual complaints of old age: aches, pains, tiredness and senior moments. People around this age are also particularly susceptible to depression.

What to do: Many seniors stay fit through low-impact exercise like aquatic workouts and Tai chi. Make sure you continue to pay attention to following a balanced diet. Your appetite may not be as hearty it was in your youth, but be sure to get adequate nutrients, fiber and protein to support your physical activity. Surround yourself with friends and loved ones who can provide emotional stimulation and support.