Exercise and Heart Health

More active and fit individuals tend to develop less heart disease than their non-active counterparts. If heart disease does develop in active and fit individuals, it occurs at a later age and is usually less severe.

In the United States, as many as 250 000 deaths per year are attributable to a lack of regular physical activity. There is a well-documented protective effect of physical activity for a number of non-cardiac chronic diseases, such as diabetes, high blood pressure, osteoporosis, and colon cancer. On the other hand, we see a higher rate of heart attacks and a higher death rate in those individuals with low levels of physical fitness. Even starting a regular exercise program in midlife through change in occupation or recreational activities are associated with a decrease in mortality. Despite this evidence, however, the vast majority of adults in the United States maintain a sedentary life-style; less than one-third of Americans meets the minimal recommendations for activity.

The Benefits of Exercise

Regular exercise has a favorable effect on many of the risk factors for heart disease. For example, exercise helps us lose weight and reduce blood pressure. Exercise can reduce "bad” cholesterol levels in the blood (the LDL level), as well as total cholesterol, and can raise the "good” cholesterol (the HDL). In diabetic patients, regular activity favorably impacts the body’s ability to use insulin to control glucose levels in the blood. The effect of continued, moderate exercise on overall heart health, when combined with other lifestyle modifications such as proper nutrition, smoking cessation, and medication use, can be dramatic.

How Much Is Enough?

Health benefits will generally occur by engaging in at least 30 minutes of modest activity every day of the week. Modest activity is any activity that is similar in intensity to brisk walking such as cycling, yard work, and swimming. It has been shown that repeated intermittent or shorter bouts of activity (such as 10 minutes) that include occupational and recreational activity or the tasks of daily living have similar cardiovascular and other health benefits if performed at the moderate intensity level with an accumulated duration of at least 30 minutes per day.

Many of the studies documenting the benefits of exercise typically use programs consisting of 30 to 60 minutes of continuous exercise 3 days per week at an intensity corresponding to 60% to 75% of the individual’s maximum heart rate (calculated as 220 - age).

Every American adult should participate in 30 minutes or more of moderate intensity activity on most, and preferably all, days of the week.

First, if you currently have heart disease or are over 45 years of age and have 2 or more risk factors such as immediate family member with heart disease before age 55, cigarette smoking, high blood pressure, abnormal cholesterol levels, diabetes, sedentary lifestyle, or obesity (BMI greater than 30), then you should consult with a health care provider before starting any type of exercise. Most people can derive significant benefits by incorporating a half hour of moderate activity into their day. If you know you are unable to integrate 30 minutes of continuous activity into your day, try to work more activities into the day by taking the stairs rather than the elevator, or try walking rather than driving a short distance to the store. The most important thing is to get started.

Delos D. Carrier, MD, MSPH
Clinton Occupational Health Clinic
Clinton, Iowa

Reference: "Exercise and Cardiovascular Health” in Circulation. 2003; 107: e2-e5 by Jonathan Myers, PhD