Posted by William on September 19, 2012
Increasing the intensity of your aerobic workout improves your body’s ability to process oxygen, gives you greater endurance, improves sports performance, makes you healthier and prolongs your life. Seems worth the effort, doesn’t it?
If you want to improve your aerobic fitness, you have to work at a sufficient intensity to convince your body to adapt. Although you can improve your health and contribute to weight management by low intensity activity, you need to work harder to reach higher fitness. This usually results in a greater ability to process oxygen. It gives you greater stamina and endurance, lets you walk, run or bike faster, improves your sports performance, makes you healthier and prolongs your life. Seems worth the effort, doesn’t it?
The usual exercise recommendation is that you work out at 60 to 90 percent of your maximum heart rate, with beginners using the lower part of the range, elite athletes at the high end, and the average exerciser around 70-75 percent. So how do you know when you’re in the range when you’re walking, running, swimming, biking, rowing, stair climbing, doing aerobics classes, or performing other aerobic (or “cardio”) activities?
You can start with your maximum heart rate. The most common way of estimating maximum heart rate is to subtract your age from 220, so that if you are 35, your maximum heart rate would be 185, and you would find your target heart rate range by multiplying that by 60 percent and 90 percent. If you want to work out between 70 and 75 percent, your range would be about 130 to 139 beats per minute. The major problem with this is that estimating your maximum heart rate this way is not accurate for everybody. In fact, you have to adjust 220 minus age by plus or minus 12 to take in 68 percent of the population, leaving one in three people still outside the range and at risk of being seriously over- or under-prescribed by using 220 minus age.
Finding your true maximum heart rate requires an expensive clinical test. If you are not an athlete, or your doctor has not had a specific medical reason to test for true max heart rate, and you don’t want to put out the money for the test, chances are you won’t know it.
Add to this the fact that many people have trouble taking their pulse accurately, especially during vigorous exercise (your pulse rate drops rapidly as you cool down).
And you see why estimating percent of an estimated maximum may not always be the best method. Note that a heart rate monitor can be a great help in getting an accurate pulse count, but you still have to estimate maximum rate.
An alternative method of gauging how hard you are working is the Rating of Perceived Exertion (RPE), also called the Borg scale. It has been widely used in both clinical and recreational applications since G. Borg developed it in 1982. If used correctly, it can be very accurate.