The following blog includes excerpts updated and modified from the 2008 Physical
Activity Guidelines for Americans. It provides advice about options for physical
activity, getting started safely, how much to do, and how often.
Brisk walking, jogging, cycling, and lifting weights are examples of health-enhancing
physical activity. Some people, for example, postal carriers and construction
workers, may get enough physical activity on the job to meet the Guidelines. Any
physical activity provides some health benefits, but research has found that most
benefits will accrue for adults from a minimum of 150 minutes (two hours and 30
minutes) a week of moderate-intensity, or 75 minutes (one hour and 15 minutes) a
week of vigorous-intensity aerobic physical activity, or an equivalent combination
of moderate- and vigorous-intensity aerobic activity.
Walking is an example of moderate-intensity aerobic activity, and jogging or running
is an example of vigorous-intensity aerobic activity. For additional and more
extensive health benefits, the Guidelines recommend that adults should increase
their moderate-intensity aerobic physical activity to 300 minutes (five hours) a
week, or 150 minutes a week of vigorous-intensity aerobic physical activity, or an
equivalent combination of moderate- and vigorous-intensity activity. The bottom
line is that more physical activity confers additional health benefits.
Aerobic activity (also called an endurance activity or cardio activity) requires sustained
use of the body’s large muscles. Examples are brisk walking, running, bicycling,
jumping rope, and swimming. They are vigorous enough to substantially
increase oxygen demand and cause a person’s heart to beat faster than usual during
a workout but do not exceed that ability of heart and lungs to keep up with the
muscle’s increased demand for oxygen. Aerobic capacity is measured in terms of
maximal oxygen uptake (VO2max) during maximal exertion.
Aerobic physical activity has three components:
• Intensity, or how hard a person works to do the activity;
• Frequency, or how often a person does aerobic activity; and
• Duration, or how long a person does an activity in any one session.
Research has shown that the total amount of physical activity is more important
for achieving health benefits than is any one of its three components: frequency,
intensity, and duration.
Anaerobic exercise is vigorous exercise, like a 100-yard dash, that causes muscles
to go into oxygen debt. In anaerobic exercise, the heart, lungs, and blood supply to
the muscles cannot keep up with their need for oxygen, and the exercise will, therefore,
be of relatively short duration.
Muscle-strengthening activity features multiple repetitions of resistance training that
causes the body’s muscles to work or hold against an applied force or weight. These
activities involve weights, elastic bands, body weight, machines for resistance, and
calisthenics. The Guidelines call for muscle-strengthening and bone-strengthening
activities on two or more days a week as these activities provide additional health
benefits. The effects of muscle-strengthening activity are limited to the muscles
doing the work, so it’s important to work all the major muscle groups of the body:
legs, hips, back, abdomen, chest, shoulders, and arms.
Muscle-strengthening activity also has three components:
• Intensity or how much weight or force is used relative to how much a
person is able to lift;
• Frequency, or how often a person does muscle-strengthening activity; and
• Repetitions, or how many times a person lifts a weight (analogous to duration
for aerobic activity).
Bone-strengthening activity is sometimes called weight-bearing or weight-loading
activity. These activities produce an increase of force on the bones that promotes
bone growth and strengthening. The needed force on bones is commonly produced
by impact with the ground. Examples of bone-strengthening activity include jumping,
running, brisk walking, and weight-lifting exercises. Bone-strengthening activities
can also be aerobic and muscle strengthening. Excellent aerobic activities
such as cycling and swimming do not do nearly as much for skeletal health as do
weight-bearing exercises such as walking and running.
This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel.