You Don't Have to Strain for Cardio Fitness
Gains
Copyright 2005 Daily News CentralQuantity may
beat quality when it comes to exercise and heart
health. Adults who engage in mild exercise --
such as walking briskly for 12 miles or exercising
moderately for 125-200 minutes over the course
of a week -- can improve their aerobic fitness
significantly and reduce their risk of cardiovascular
disease, according to a study published in Chest.
"The
classic exercise regimen has a component of intensity
up to 80 percent of someone's maximum for health
benefits," says lead author Brian D. Duscha of
Duke University Medical Center in North Carolina."Our
study demonstrates that you can exercise at an
intensity much less than that and still achieve
fitness benefits," he notes."People find exercise
'hard' and few people want to exercise at an intensity
higher than they have to.
Walking briskly for 12 miles a week per week
is realistic and does not require anyone to incorporate
a hardcore training regimen. Increasing your mileage
or intensity will give you even greater health
benefits," Duscha says.Improved Oxygen ConsumptionA
Duke Medical Center research team examined the
effects of different exercise training regimens
on 133 patients aged 40 to 65 years. All were
sedentary, overweight nonsmokers who had abnormal
levels of fat in their blood.
The participants
were divided into four exercise groups:- high-amount/high-intensity
(HAHI), the equivalent of jogging 20 miles per
week at 65 to 80 percent peak Vo2 (maximum oxygen
consumption);- low-amount/high-intensity (LAHI),
the equivalent of jogging/walking up an inclined
treadmill approximately 12 miles per week at 65
to 80 percent peak Vo2;- low-amount/moderate intensity
(LAMI), the equivalent of walking approximately
12 miles per week at 40 to 55 percent peak Vo2;
and- a control group of nonexercising patients.
All patients underwent cardiopulmonary exercise
testing twice at baseline and after seven to nine
months of exercise training.All exercise groups
significantly improved their absolute and relative
peak oxygen consumption and time to exhaustion
(TTE) compared to baselines scores.Increasing
Intensity May Help TooAlthough the HAHI group
showed the greatest improvements in peak Vo2 overall,
increasing exercise intensity from 40 to 55 percent
to 65 to 80 percent (at a controlled amount of
12 miles/week) did not significantly improve peak
oxygen consumption.
However, increasing the amount
of exercise did produce improvements.An increase
in exercise amount also demonstrated a graded
increase in TTE between groups, although data
were not statistically significant."Although our
results did point toward amount being more important,
it is very likely fitness levels can be improved
by increasing either amount or intensity," says
Duscha."This is illustrated by the tiered effect
the exercise dose had on fitness improvements
across our groups. We believe with more people
in the study, increasing intensity would also
have been significant," he explains.
Losing Weight Not EssentialBody mass index (BMI)
was reduced in the LAHI and HAHI, groups but remained
unchanged in the LAMI group. All exercise groups
lost an average of 2.87 pounds after exercise.
Baseline characteristics of age, BMI, weight,
peak and relative Vo2, and TTE were not different
between the groups."A second very important message
is that subjects enjoyed fitness benefits in the
absence of weight loss. Many people exercise with
the purpose of losing weight. When they do not
lose weight, they do not think the exercise is
benefiting them and they stop exercising," notes
Duscha.
"The truth is, you can improve your cardiovascular
fitness and reduce your risk for heart disease
by exercising without losing weight. Even if individuals
do not lose weight, it is likely that they will
lose body fat and increase lean muscle mass while
reducing other risk factors," he points out.12
Miles a WeekAdherence to exercise requires motivation
and making exercise a priority, the researchers
stress.
They advise those who are beginning an
exercise regimen to start slowly, choose an enjoyable
activity, and make exercise a social activity.
Individuals with medical problems should consult
a physician before starting an exercise program."If
you distill our results down, the public health
message is: You only need to walk briskly for
12 miles per week or for approximately 125 to
200 minutes per week to improve your health.
This sheds more light on the question, 'What
is the minimum amount of exercise I need to do
to get a health benefit?'" says Duscha."Regular
exercise is an important part of a well-balanced
lifestyle," adds Paul A. Kvale, MD, FCCP, President
of the American College of Chest Physicians.
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