HOW HARD SHOULD YOU SWIM?

There is no way around it. If you want cardiovascular benefits from any exercise, you are going to have to make your heart work. But how hard? If you are over thirty-five, be sure to consult your doctor before starting any fitness program. The same holds if you are under thirty-five and have any major risk factors for heart disease, such as high blood pressure. But once you have gotten the go-ahead, you have to determine how much you want to exercise your heart and lungs.

To come to some intelligent guidelines that will work for you, you will need to do a few calculations. The first is heart rate, simply the number of times your heart is beating in a minute. Place your finger where you can feel your pulse in the hollow at the upper inside area of your wrist or at the side of your neck and count the beats for five seconds. Then multiply that number by 12. The answer will be your heart rate. If you do this when you haven’t been exercising, the number is your resting heart rate (RHR).

Next you have to compute your maximum heart rate (MHR), the most times a minute a heart your age should beat. You can do this by subtracting your age from 220. Thus, if you are 40, your MHR is about 180.

The next number you will have to know is your training range, the range within which you want to keep your heart rate while exercising so that it is high enough to do your heart some good but not so high that it creates a risk for you. To calculate your training range, multiply your MHR first by .60, which will give you the lower threshold of your training range, and then by .80, to establish a safe upper limit. For a forty-year-old, the training range is between 108 to 144 beats per minute. Or you can just consult Table 3.4.

 

Table 3.4, based on AHA recommendations, is easily understood and simple to use. But it is only a rough approximation. If you would like a more precise estimate of your training range, there is a more complicated formula that yields a more personal value. Its advantage is that it takes into account improvements in your aerobic fitness level as you continue training. Here’s how it works:

First figure your maximum heart rate (MHR) by subtracting your age from 220.

Then find your resting heart rate (RHR), preferably just before you get out of bed in the morning.

Now, calculate your target heart rate using these two formulas:

0.6 (MHR - RHR) + RHR

0.8 (MHR - RHR) + RHR

If you are thirty-five years old and have a resting heart rate of 55, it would work out this way:

0.6 (185 - 55) + 55 = 0.6 × 130 + 55 = 133 minimum rate

0.8 (185 - 55) + 55 = 0.8 × 130 + 55 = 159 maximum rate

So, because your heart is now in good shape, as indicated by your low RHR, 55, your heart rate while swimming should be a little higher than the range in the table.