Although I promote fitness and regular exercise, I have never been to an aerobics class. Some of my patients have come to me with injuries sustained in aerobics classes, so I have promoted safer forms of exercise such as walking, swimming, water exercises, yoga, tai chi and stretching.

I did, however, attend a course teaching physical therapists how to conduct a safe aerobics class for people with spinal problems and other special needs. It was based on sound bio-mechanical principles and how to exercise safely while having a good time.

In general, aerobics classes developed from the dance community, hence the dance-like movements and music. Some aerobic movements actually put a great deal of stress on the spine, especially those bringing the upper body into a flexed position. Also, people tend to work harder than is safe and many times the instructor encourages them to keep up. In yoga and other forms of group exercise, people are encouraged to move at their own pace.

Several formulas exist to monitor safe exercise levels. Some are fairly complicated and calculate what is called “target heart rate,” which can be estimated by an individual or determined through specific testing by a trained person. Pacemakers, cardiac conditions and other medical problems can affect this, so if you have special needs, please consult your physician. If you learn to take your pulse and count for a 10-second interval, you can monitor your own fitness level.

Rate of perceived exertion is another way to do it. For beginners, it is recommended you stay between light to somewhat hard levels of exertion and at 55-60% of your maximum target heart rate. At birth, the heart rate is 220 beats/minute maximally. Thereafter, subtract 1 from 220 for each year to estimate maximum heart rate. A 40-year-old would have a maximum heart rate of about 220 minus 40 = 180 beats/minute.

The instructor said fitness could be determined by how quickly you recover from activity.  Most people are short of breath after climbing a flight of stairs. The fit person recovers in a minute or less, but an unfit person may take 5 minutes or longer.

The larger muscles of the body, i.e. those in the legs, require more blood circulating to them. The heart undergoes a strengthening effect when this additional volume of blood stretches the heart. If you exercise 30-60 minutes twice a week using the leg muscles, your heart will get stronger. Surprisingly, adding the arms to the activity increases the heart rate but not necessarily the volume of blood getting pumped to the heart. Therefore, when doing aerobic exercise, the main concern should be the exercise your legs are doing.

If you have any questions or are interested in participating in a safe aerobics class, feel free to call.

Qigong, Chinese energy classes. Try a no-impact qigong class. Your first class, a $30 value, is free! Classes are held at Y.P.T. Call for more info.

Sheila Yonemoto, P.T., has been a physical therapist for over 30 years, specializing in Integrative Manual Therapy utilizing a holistic approach. She can be reached at Yonemoto Physical Therapy, 55 S. Raymond Ave., Suite 100, Alhambra, CA  91801. Call (626) 576 0591 for a free consultation and insurance evaluation, or visit her website for more information. Opinions expressed in this column are not necessarily those of The Rafu Shimpo.

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  1. Certain medications which affect the heart rate will also make the pulse an unreliable parameter for monitoring intensity of exercise. This is when rating of perceived exertion is a better measure to use, correct?