We're all aware that the body goes through some major changes over the years. Combinations of natural and man-made forces work together to push us further down the path to old age. It sounds depressing, but luckily we're not totally helpless against this process.

Staying fit and healthy makes all the difference when it comes to the aging process. You can't avoid getting older, but you can help your body roll with the punches the years throw so you can be in the best shape for your age.

Fitness isn't just an exercise routine; it's important to take the condition of body, mind and spirit into consideration when you want to be your best.

In Your 20's

Pros: You're probably in good shape, or have the ability to improve your body fairly quickly. Your energy and strength are high. You're finding your place in the adult world and really experiencing your independence. Your mental outlook is probably hopeful.

Cons: You may abuse your body and push yourself to the limit, working, partying, and/or studying too hard. Your diet might consist mainly of pizza pockets and diet soda. Your responsibilities possibly keep you seated for long periods, leading to unwanted weight gain. There may be lots of stress and drama involved with school, relationships and entering the workforce.

What to do: You have the energy; you just need to take control and plan your activities more wisely. If you find yourself sitting a lot, make sure you get some physical activity. Walk to work, take the stairs instead of the elevator, or find a running buddy to do some laps around campus. Invest in some weights or a yoga DVD. Cut back on the junk food. Switching from soda or sugary drinks to water is a great idea. You may not have the time or skills to create gourmet meals, but throwing together a salad or boiling some eggs are simple and doable ways to get healthy natural foods on your table.

In Your 30's

Pros: You're still relatively young, and your muscles are still in pretty good shape. You're probably being kept busy with work and/or children. Thanks to increased maturity, you're taking better care of yourself and you're likely to have found what works for you when it comes to fitness routines and diet. You're at your sexual peak, which can add some nice passionate energy to your life.

Cons: If you're a mom, the changes that happen to your body following the birth of your children will be your primary challenge. The metabolism starts slowing down in your 30's so the fitness tricks that worked for you in your 20's may not be as effective now, plus, added family responsibilities can get in the way of "you time," which is vital to your mental and physical health.

What to Do: Help yourself get back into shape after childbirth by doing a gentle routine that focuses on regaining your core strength and conditioning your pelvic floor muscles. As your little one grows, you can turn your attention to losing some of that baby weight. Just remember to keep the metabolism burning. Play with your kids or take the dog on nice long walks. Always providing for the needs of others and ignoring your own needs isn't beneficial to your health. You may end up overeating to dull your emotions or becoming sedentary from depression. Always take some time out to pamper and enjoy yourself with activities you love.

Your 40's

Pros: The 40's tend to be the decade of gaining real self-confidence and comfort in your skin. This contributes to your fitness because as you learn what works for you, you can put it to use in ways that work for your body type and needs. Family-wise, the picture varies. Women these days are having children at widely disparate ages, so at 45 you may have a young school-age child to run after, while your friend of the same age may be facing empty nest syndrome as her kids leave home.

Cons: Your muscles are on the wane, so you may start to notice the dreaded "sag" if you haven't already. You may not have quite as much energy and flexibility as you did a few years ago, and realizing this might get you down.

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.