As you begin your aerobic exercise your heart rate increases. During lowintensity work out, your heart rate will reach a constant rate that you can sustain for a period of time. As you intensify your exercise, you will gain a proportional increase in your heart rate. In other words, the intensity of exercise is directly proportional to the increase in your heart rate. The faster you walk, the faster your heart will beat.

What’s the maximum heart rate?
Clinically, the normal heart rate is 60 to 100 beats per minute. The normal number of heart rate per minute and that of pulse rate per minute are the same. But when we talk of aerobic exercise, the maximum heart rate differs from person to person. The difference might be 10 to 20 beats per minute. Maximum heart rate in aerobic exercise declines with age. Thus the maximum heart rate that a 60- yeal old can tolerate will be much less than that of a 20-year old. Maximum heart rate is 220 minus your age. If you are 50 years old, by substitution, your maximum heart rate is 220 – 50. Thus your predicted maximum heart rate is 170 beats per minute.

How hard should you work your heart?
The best way to strengthen your heart is through exercise. You should push your heart rate above the clinical level (above 60-100 beats/minute) and sustain it for a period of time. You should increase your intensity of exercise in order to attain this and thus the right intensity is not how fast you run, walk, swim, or cycle but how your heart, lungs, and muscles respond to the exercise.

Here’s a simple fitness prescription for you
n order for you to understand this simple advice, you have to appreciate and understand the following: How often you exercise is referred to as frequency. How hard you do it is intensity. How long you exercise is called time. Here’s a simple guideline: Frequency: Exercise 3 to 5 times a week; Intensity: Exercise at 60 to 90% of maximum heart rate; and Time: Exercise 20 to 60 minutes per session.

How to know your target heart rate?
But what if you can’t intensify further to get to the maximum? You have to at least reach your target heart rate. It is the rate at which you train. It depends on how you can hold on to your target heart rate. The lower level of the maximum target is computed as 220 – age multiplied by .60 while the upper level is 220 – age multiplied by .90. By substitution, if you are 50 years old: Your lower limit is 220 – 50 x .60 = 102 beats per minute. Your upper level is 220 – 50 x .90 = 153 beats per minute.

Pay attention on how you feel. If you feel uncomfortable at 60%, back off and start over again. You will be able to keep up with the exercise through repetition.