Treadmill Testing Can Help Save Women's Lives
by Lisa Drayer, MA, RD
September 26, 2003
The News:
Treadmill testing may help to protect women against heart disease,
which claims the life of 1 of every 2 women in the U.S., according to a study
in this week's Journal of the American Medical Association.
The Scoop:
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What is a Treadmill Test?
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| According to Samia Mora, lead author of the JAMA
study, a treadmill test is a test where an individual walks on a treadmill
that starts at a relatively low speed and is gradually increased in incline
and speed while his or her heart rate, blood pressure, and EKG (electric
activity of the heart) are monitored continuously. The protocol that was
used for this study was the standard Bruce protocol, where the incline and
speed are increased every 3 minutes, starting at incline of 10% and speed
of 1.7 mph. |
Until now, it's been known that abnormalities on treadmill tests—or what
we think of as a stress test—is associated with increased mortality in
healthy men, but the relationship in women hasn't been clear. Well, now we have
the answer. After testing about 3,000 women without any known symptoms of heart
disease, such as chest pain or angina, researchers from Johns Hopkins determined
that three different factors on a stress test are independently associated with
increased risk of cardiovascular deaths in women.
Those factors include:
Low exercise capacity (in other words, a short time spent on the treadmill
when women were given a specific protocol with increasing intensity)
Low heart rate recovery (the ability of the heart rate to return to
normal after the highest intensity exercise is reached)
Not achieving target heart rate during the test (target heart rate is
a measure of cardiovascular fitness and is associated with lower risk of disease).
In fact, women who scored in the lowest categories for these factors had three
and a half times greater risk of cardiovascular death as compared to those who
scored in the highest categories, and that's after taking into account risk
factors such as being overweight, and having high cholesterol and high blood
pressure.
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Should I Get a Treadmill Test?
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Mora says women certainly may request this, although it may not be covered
yet by insurance. It costs around $100 to get a treadmill test, and it
will provide additional information about a women's cardiovascular risk
beyond what is obtained by the traditional risk factors. "If a woman's
heart rate recovery or exercise capacity is low, she may become more motivated
to increase her physical activity" says Mora.
If, for any reason, a physician orders a treadmill test, a woman should
ask about her heart rate recovery and exercise capacity levels, and discuss
the results with her health care provider. In addition, women who have
family history of premature coronary disease or who want to know their
risk beyond what is given in the traditional risk factors, may request
to have such a treadmill test done. "The current AHA and ACC guideline
recommendations say that using treadmill testing for asymptomatic individuals
if they have 2 or more traditional risk factors may be helpful for determining
their risk. However, in our study, the treadmill test helped to determine
risk even in women without many risk factors, says Mora."
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So, the good news is that even if the genetics aren't in our favor (whether
it's because we're overweight or have high cholesterol, diabetes, or family
history of disease), we can help to reduce our risk by increasing our physical
activity. That's was one of the most motivating findings of this study, that
is, even if you have these existing risk factors, if you are able to achieve
a certain level of physical fitness as indicated by these tests, you are reducing
your risk for disease and death from disease.
"There is great interest in tests that predict cardiac risk in asymptomatic
women, since two-thirds of women who die suddenly were asymptomatic until time
of death," says lead author Samia Mora, MD, MHS, of the Division of Cardiology
of the Johns Hopkins Medical Institutions. Clearly, exercise capacity and heart
rate recovery merit consideration as strong predictors of cardiac risk, incremental
to the traditional risk factors."
Treadmill vs. Elliptical—Which is Best?
Both the treadmill and the elliptical are weight-bearing exercises, meaning
that you must support your entire body weight while exercising. This is really
good in terms of preserving bone mass which tends to decline as we age—that
is, by supporting your entire body, you are placing a stress on the skeletal
system, including the bones in your legs and lower spine, which helps to protect
against osteoporosis, and you are also preserving muscle mass, which tends to
decline with age.
"Swimming or even biking are both great exercises, but they don't place
the same degree of stress on the skeletal system, so you're not preserving the
bones as much," says Fred Kolkhorst, PhD, Associate Professor of Exercise
and Nutritional Sciences at San Diego State University, and Fellow in the American
College of Sports Medicine.
Treadmill: No learning curve, great impact
The main advantage of the treadmill is that there is no learning curve. It's
easy to use a treadmill—you can just get on and start
moving! It's very good for those who are thinking about starting an exercise
program; it's also good in terms of stress placed on the skeletal system.
Elliptical: No impact, good for those with joint issues
With the elliptical, you're not necessarily getting the biggest bang for your
bone so to speak. However, it is a better option for those with joint
issues—for example, if you have a loss of cartilage,
which is the cushion for the knees or the hips (these joints absorb the greatest
stress), you are better off doing exercise that has less impact, because you
can wear out the joints out faster and it can be really painful, says Kolkhorst.
The movement can also prevent overuse injuries, says Gregory Florez, Spokesperson
for the American Council on Exercise and CEO of FitAdvisor.com.
"You can go forward and backwards, which can help prevent overuse injuries
common in runners and walkers." Common overuse injuries include shin splints,
pulled hamstrings, hip pain, and a variety of food related problems due to impact
and overuse, says Florez.
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Lisa Drayer, MA, RD is the Director of Nutrition Services
for DietWatch.com. Lisa has provided nutrition counseling to clients, has
written material for books and health Web sites, and has appeared in several
national magazines and on television as an expert in the nutrition field. |
