Heart Rate Training Zones – On Improving Fitness

Article by Gerald Flume

Want to improve your physical fitness, including your heart? Increase your physical stress. Of course there are right and wrong ways of doing this, but an analogy might get us started.

I. The benefits of (physical) stress for physical fitness

Tulip growers try to maximize the number of bulbs they grow per square meter or foot of available soil. But when the plants grow close together, they each tend to reduce the wind drag per plant among their neighbors at the same time that they all compete for the same square inches of sunlight as they grow upward. The result is thin stems, so thin that a mature plant cannot hold the flower and head upright by itself. So the tulip growers gently pass their extended arms over the tops of the growing plants to give the stems a little stress. Not enough to break them, but enough to stress them into growing thicker, stronger stems.

Humans tend to lose physical strength where there is too little physical stress or muscular exercise. One of the best ways to increase muscular strength and efficiency is known as interval training where intervals of more and less intense exercise and rest are interspersed. A core feature of interval training is switching between aerobic and anaerobic exercise.

II. Interval training builds strength and endurance

Anaerobic exercise is intense and brief. One’s heart is racing near its maximum and the muscles are burning glycogen in the presence of very little available oxygen (anaerobic means “no oxygen”). This is especially the kind of stress that “thickens the stem” in humans, or rather than stimulates the muscles to build up. Especially as people age, anaerobic exercise becomes increasingly important for maintaining physical strength and endurance.

But anaerobic exercise of course comes at a price, and here is where consultation with a doctor becomes critical for advice that may enable one to avoid injury or sometimes a heart attack, especially if a person has certain physical conditions or is on some kinds of medication. Know your reasonable limitations beforehand. And in all cases of anaerobic exercise, a price is the build up of lactic acid and other waste products in the muscles resulting in physical symptoms of pain and exhaustion.

Intervals of rest or lesser exercise then become necessary in order to flush out and oxidize the lactic acid in the blood stream and elsewhere. Aerobic exercise relies on “burning” oxygen along with “fuel” like carbohydrates. It is less intense than anaerobic exercise, and can be carried on for relatively longer periods of time.

Varying periods of rest have their own benefits in the process too, such as to rebuild and strengthen damaged muscle tissues with proper nutrition. And warm ups and cool down periods play into the regimen for things like muscle stretching and metabolic preparation. In interval training, periods of more and less intense exercise plus rest are repeated. This has proven more efficient and effective than prolonged aerobic exercise alone for many sports activities.

III. Interval training pegged to heart rate zones

One of the key means of measuring and progressing in interval training then becomes heart rate zones. Although these may at times be a bit fuzzy and variable around the edges, nonetheless heart rate zones can be a usefully pegged, for example, to anaerobic versus aerobic exercise periods or to rest or warm up versus aerobic exercise.

A heart rate within such-and-such beats per minute range should be maintained for so-many seconds or minutes for a given individual for a given section of interval exercises. As one moves in training from less fit to more, the ideal intervals of heavier exercise will increase and rest periods decrease or move farther apart. And again, where heart rate is measured, such as conveniently with technology, heart rate ranges defined as heart rates zones. Heart rate zones then identify or help identify levels of exercise, particularly aerobic versus anaerobic versus rest.

For a healthy person at least, heart rate zones are mapped out typically based on heart rate measured at rest (minimum beats per minute) and at very heavy exercise (maximum heart rate). The latter can become problematic especially where health concerns come into play, but in less precise fashion, can be taken as 220 minus age before the age of 30, with a beats per minute tappering off more slowly after age 30, especially for a healthy person. And there are other related or unrelated means as well.