Over the past 25 years, the United States has experienced a steady
decline in the number of deaths from cardiovascular disease (CVD), primarily
in mortality caused by coronary heart disease and stroke. Still, coronary
heart disease is the leading cause of death while stroke is third. Lifestyle
improvements by the American public and better control of the risk factors
for heart disease and stroke have been big reason for this decline.
Coronary heart disease and stroke have many causes. Modifiable
risk factors include smoking, high blood pressure, blood lipid levels, obesity,
diabetes, and physical inactivity. National trends observed with smoking,
high blood pressure, and high blood cholesterol have improved, but obesity
and physical inactivity have not. Advanced technologies have taken the place
of physical activity in many daily tasks. Unfortunately, most Americans are
physical inactive.
Physical activity protects against the development of CVD and
also improves other CVD risk factors, including high blood pressure, blood
lipid levels, insulin resistance, and obesity. Physical activity is also important
in the treatment and management of patients with CVD or increased risk, including
those who have hypertension, stable angina, a prior myocardial infarction,
peripheral vascular disease, or heart failure. Physical activity is important
for cardiac rehabilitation, and people with CVD may benefit from it.
Advantages to an Active Lifestyle
Physical inactivity among the U.S. population is now widespread.
About one in four adults (more women than men) currently have sedentary lifestyles
with no leisure time physical activity. An additional one-third of adults
are insufficiently active to achieve health benefits. The prevalence of inactivity
varies by gender, age, ethnicity, health status, and geographic region but
is common to all demographic groups.
Girls become less active than boys as they grow older. Children
become far less active as they move through adolescence. Obesity is increasing
among children. It is related to an energy imbalance (i.e., calories consumed
in excess of calorie expenditure.) Data indicate that obese children and adolescents
have a high risk of becoming obese adults, and obesity in adulthood is related
to coronary artery disease, hypertension, and diabetes. Thus, the prevention
of childhood obesity has the potential of preventing CVD in adults.
There is evidence that increased physical activity leads to weight
loss and that combining physical activity with reducing food intake can increase
and help to maintain loss of body weight and body fat mass.
Middle-aged and older men and women who engage in regular physical
activity have significantly higher high-density lipoprotein (HDL) cholesterol
levels than do those who are sedentary. When exercise training has extended
to at least 12 weeks, the HDL cholesterol levels are even more improved.
What Type, Intensity, and Quantity of Exercise Are Best?
You don't need a structured or vigorous exercise program to reduce
CVD risk factors and gain many other health benefits. Most benefits of physical
activity can be gained by performing moderately intense activities.
Everyone should maintain regular physical activity at a level
appropriate to his or her abilities and interests. Both children and adults
should have at least 30 minutes or more of moderate-intensity physical activity
on at least five, if not all days of the week. However, physical activity
must be performed regularly to maintain positive effects. Intermittent or
shorter bouts of activity (at least 10 minutes), including tasks of daily
living, also have similar cardiovascular and health benefits if performed
at a level of moderate intensity (such as brisk walking, cycling, vacuuming,
and yard work) for a total of 30 minutes daily. People who currently meet
the recommended minimal standards may gain additional health and fitness benefits
from increasing their activity. Higher intensity or longer duration activity
could be performed approximately three times weekly and achieve cardiovascular
benefits, but low-intensity or shorter duration activities should be performed
more often to achieve cardiovascular benefits.
People who are not currently active should gradually build up
to the recommended goal of 30 minutes of moderate activity daily by adding
a few minutes each day until reaching their personal goal to reduce the risk
of injury.
Developing muscular strength and joint flexibility is also important
for an overall activity program to improve one's ability to perform tasks
and to reduce the potential for injury. Resistance training may contribute
to better balance, coordination, and agility that may help prevent falls in
the elderly.
Physical activity carries risks as well as benefits. The most
common adverse effects of activity relate to musculoskeletal injury and are
usually mild and self-limited. The risk of injury increases with increased
intensity, frequency, and duration of activity and also depends on the type
of activity. Exercising in moderation can reduce these injuries.
Because the risks of physical activity are very low compared with
the health benefits, most adults do not need medical consultation before starting
a moderate-intensity physical activity program. However, those with known
CVD and men over age 40 and women over age 50 with multiple cardiovascular
risk factors should have a medical evaluation prior to initiating such a program.
