| How
to help clients select and monitor effort level by Reed Humphrey,
Ph.D., P.T. In a perfect world,
everyone would visit a healthcare provider for a graded exercise stress test before
starting an exercise program, from which specific exercise targets could be derived,
i.e. appropriate exercise heart rate or workload. In reality, a stress test is
a wise investment for those who are inactive, have a history of heart or circulatory
problems, and/or have the accepted risk factors for heart or circulatory problems
(i.e. smoking, high blood pressure, high cholesterol or diabetes or a family history
of these problems) as the test screens for exercise safety. When
an individual is thought to be healthy and already activethe assumption
when a healthcare provider decides against a stress test health and wellness
professionals can suggest a submaximal fitness test, in which the client's heart
rate and perceived exertion information is collected while he/she exercises on
a treadmill or cycle ergometer. (Again, it's assumed the client is healthy and
that a medically unsupervised test is safe for him/her.) Following the test, the
health or wellness professional can provide this individual with specific parameters
for exercise effort based on this evaluation. If
the submaximal test is not available, health and wellness professionals can suggest
that clients measure their exercise heart rate using common formulas, such as
subtracting their age from 220 to predict maximum heart rate, or that they subjectively
assess their effort through breathing or "conversational limit" effort.
Legitimate concerns have been
raised about the 220-minus-age formula. These concerns include the scientific
knowledge that people's ability to predict their maximum heart rate varies substantially
at any given age. Commonly, people will err by 10 beats in either direction, or
even twice that magnitude. A newer formula was recently introduced that reduces
the prediction error, but only slightly, and this error is known to increase even
more so in older adults. In addition, a variety of medications, such as beta-blockers,
influence the heart rate response, so the risk of using a prediction equation
to estimate exercise intensity probably exceeds the benefit and is not recommended,
particularly for older adults. No
matter the intensity level at which older clients exercise, they should consult
their healthcare provider before continuing an exercise program if they have any
unusual discomfort, dizziness or lightheadedness during exercise, or if they feel
excessively fatigued or "just don't feel right." Reed
Humphrey, Ph.D., P.T., is an associate professor in the Department of Physical
& Occupational Therapy at Idaho State University. He is currently U.S. Delegate
and Secretary-General, World Council for Cardiovascular and Pulmonary Rehabilitation,
plus a fellow and past president (1995-96) of the American Association of Cardiovascular
and Pulmonary Rehabilitation. Humphrey is also a fellow of the American College
of Sports Medicine, and served as associate editor of ACSM's Guidelines for Graded
Exercise Testing and Prescription, fifth edition, and the recently published ACSM's
Resources for Clinical Exercise Physiology. |