Walk Your Way to a Healthier Heart
Engaging in moderate-intensity exercise, such as walking several miles per week, may reduce the risk of cardiovascular disease, reports the journal Chest (2005;128:2788–93).
Cardiovascular disease (CVD) is a leading cause of death and disability in the United States. It can manifest as heart attack, stroke, heart failure, or blockage of arteries in the lower extremities (peripheral artery disease). Factors including smoking, sedentary lifestyle, obesity, diabetes, high blood pressure, and elevated blood lipids (cholesterol, triglycerides) may contribute to the development of CVD.
Regular physical activity helps reduce CVD risk, but the exact amount and intensity of exercise that is needed to achieve this benefit have not been previously determined.
In order to make recommendations about exercise training for CVD prevention, the new study compared the effects of three different exercise protocols in people who were at high risk for developing CVD. The seven- to nine-month exercise-intervention study included 133 sedentary, overweight men and women (average age 52 years) with high cholesterol. They were assigned to one of the following groups: (1) low amount/moderate-intensity exercise (equivalent to walking about 12 miles per week); (2) low amount/high-intensity exercise (equivalent to jogging about 12 miles per week); (3) high amount/high-intensity exercise (equivalent to jogging about 20 miles per week); or (4) a non-exercising control group.
At the beginning and end of the study, the people underwent an exercise test on a treadmill to determine their cardiovascular fitness level. Peak oxygen consumption (a direct measure of cardiovascular fitness) and time to exhaustion (a somewhat less-sensitive measure of physical fitness) were evaluated. Time to exhaustion is often used to estimate cardiovascular fitness when it is not feasible to measure peak oxygen consumption.
By the end of the study, the men and women in all three exercise groups had significant improvements in peak oxygen consumption and time to exhaustion compared with baseline values. Compared with the control group, time to exhaustion improved significantly in all three exercise groups, and peak oxygen consumption improved in the high-intensity exercise groups.
It is interesting to note that increasing the intensity of exercise from moderate to high did not result in substantial gains in cardiovascular fitness, whereas increasing the time spent exercising did. This suggests that the amount of time spent exercising is more important than the exercise intensity for improving cardiovascular fitness.
Based on these findings, the authors of the study recommend walking for a minimum of 12 miles per week to improve cardiovascular health and to help decrease the risk of CVD.
Kimberly Beauchamp, ND, earned her bachelor’s degree from the University of Rhode Island and her Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. She cofounded South County Naturopaths in Wakefield, RI. Dr. Beauchamp practices as a birth doula and lectures on topics including whole-foods nutrition, detoxification, and women’s health.
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