Researchers at Johns
Hopkins have determined that in people age 55 to 75, a moderate program of
physical exercise can significantly offset the potentially deadly mix of risk
factors for heart disease and diabetes known as the metabolic syndrome.
More specifically, the researchers found that exercise improved overall
fitness, but the 23 percent fewer cases were more strongly linked to reductions
in total and abdominal body fat and increases in muscle leanness, rather than
The researchers' findings raise the importance of physical exercise in
treating both men and women with the metabolic syndrome, a clustering of three
or more risk factors that make it more likely for a person to develop heart
disease, diabetes and stroke - including high blood pressure, elevated blood
glucose levels, excess abdominal fat and abnormal cholesterol levels.
The study, to be published in the American Journal of Preventive Medicine and
available online Dec. 30, is believed to be the first to focus on the role of
exercise training in treating metabolic syndrome in older persons, a group at
high risk for heart disease and diabetes.
"Older people are very prone to have the metabolic syndrome," said lead study
investigator and exercise physiologist Kerry Stewart, Ed.D., professor of
medicine and director of clinical exercise physiology and heart health programs
at The Johns Hopkins University School of Medicine and its Heart Institute.
"While each component of metabolic syndrome increases disease risk by itself,
when combined, they represent an even greater risk for developing heart disease,
diabetes and stroke."
To assess the benefits of a fixed program of exercise training, the Hopkins
team studied a group of 104 older people for a six-month period between July
1999 and Nov. 2003. All of the participants had no previous signs of
cardiovascular disease beyond untreated, mild hypertension. One half of the
study participants were randomly assigned to a control group that received a
booklet that encouraged increased activity, such as walking, to promote good
health. The other half participated in a supervised series of exercises for 60
minutes, three times per week. The combination of exercises was designed to work
all major muscle groups, the heart and circulation. These included aerobics on a
treadmill, bicycle or stepper, plus weightlifting.
The Hopkins team measured the changes in participants' risk factors, body
fat, and muscle and fitness levels, and found substantial improvements in the
group that was exercising for six months. Aerobic fitness, as measured by peak
oxygen uptake on a treadmill, increased by 16 percent, and strength fitness
increased by 17 percent. The average weight loss in this group was only four
pounds because much of the loss of fat was offset by increased muscle mass. The
fat in the abdominal region, by itself an important risk factor for heart and
metabolic syndrome, was reduced by 20 percent among people in the exercising
group. The group that was not exercising had either no or significantly less
improvement than the exercising group.
At the beginning of the study, 43 percent of all participants had the
metabolic syndrome. By the end of the study, participants in the exercising
group had no new cases of metabolic syndrome, and the condition had resolved in
nine of them, a reduction of 41 percent. In the control group, eight
participants no longer had the syndrome, while four new cases appeared,
resulting in an overall reduction of only 18 percent.
"Older people can benefit greatly from exercise, especially to reduce their
risk for developing metabolic syndrome," said Stewart. "Our results show that
this population can be motivated to follow through with a moderate exercise
program, and for some risk factors, such as abdominal fat, exercise can be as
effective as what is accomplished today with drugs.
"A novel finding of our study was that the changes in disease risk factors
with exercise training were more closely related to reductions in body fat,
particularly abdominal fat, and increases in muscle tissue, rather than
improvements in fitness.
"The results also confirm the value of exercise for managing multiple risk
factors. Because so many older persons have or are at risk for metabolic
syndrome, this study provides a very strong reason for individuals to increase
their physical activity levels. They will reduce their fatness, and increase
their fitness and leanness, while reducing their risk for heart disease and
Estimates of the prevalence of metabolic syndrome range from 25 percent to 40
percent of American adults age 40 and older.