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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.
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