But she found a renewed motivation when she started practicing the martial arts.

"Since I began training in the martial arts in my mid-40s, working out is (benefiting) both mind and body, and it is challenging and fun, rather than something I have to do just to stay in shape. I look forward to training and continuing to improve," Maccabee said.

For those who don't exercise as intensely as Maccabee does, Reames said that baby boomers need to be aware that they can't be a "weekend warrior" who competes at top form for one day and then needs days to recover. To avoid this, Reames said to be aware that you might not be able to compete in the same activities, or at the same level, that you did when you were in your 20s.

Some activities Reames recommends for baby boomers are weightlifting and body resistance exercises.

Weightlifting is good for developing bone mass, and can help women fight osteoporosis, Reames said. According to the IHRSA, calcium alone may not strengthen bones, and strength and aerobic exercises might also be needed. The IHRSA recommends that older adults should spend at least two days a week focusing on muscle-strengthening activities that involve all of the major muscle groups: the legs, hips, chest, back, abdomen, shoulders and arms.

To target some of those key muscle groups, Reames suggests doing squats and lunges, which not only help build muscle, but also mimic activities people do in real life -- such as picking things up and climbing stairs.

However, Reames reminds you that you should use caution when performing any physical activity. He suggests staying away from fast, quick movements that don't allow you to have complete control over your body, as they might put your body through something its not ready for. Also, he says to pay attention to your form -- and your posture -- while doing the exercises, and to listen to your body.

"If it hurts, don't do it," Reames said. "Pain is your body's method of communicating."

Reames also suggests always warming up before you partake in any activity -- even if you're just planning on cleaning out the garage -- and to also listen to your doctor's advice, as he or she knows exactly what your body can and cannot do.

Exercise Can Be Cost-Effective

If the economy has you shying away from a gym membership, the IHRSA encourages you to compare the long-term costs of exercise versus health care.

According to the IHRSA, a 2008 study of people who averaged at least two health club visits per week over two years spent at least $1,252 less in health care costs than did those people who went to the club less than once a week.

The organization also said that obese adults who are more than 30 pounds overweight have medical costs that are $5,000 to $21,000 higher than those of healthy weight individuals.

Turn Your Home Into A Gym

If joining a gym still doesn't fit into your budget, or maybe you just don't like the gym atmosphere, Reames has tips for how you can get in shape at home.

"When I walk into a house, I see a gym," Reames said.

Some of the fitness expert's suggestions include filling up water bottles to use as weights, using inexpensive elastic bands for resistance; getting on the floor for push-ups, squats and abdominal work; using a chair for dips to work your shoulders and triceps; and getting in your cardiovascular work by taking a walk outside.