Does Aerobic Exercise Slow Progression of Atherosclerosis?

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The summary below is from the full report titled "Effects of Aerobic Physical Exercise on Inflammation and Atherosclerosis in Men: The DNASCO Study. A Six-Year Randomized, Controlled Trial." It is in the 15 June 2004 issue of Annals of Internal Medicine (volume 140, pages 1007-1014). The authors are R. Rauramaa, P. Halonen, S.B. Väisänen, T.A. Lakka, A. Schmidt-Trucksäss, A. Berg, I.M. Penttilä, T. Rankinen, and C. Bouchard.

What is the problem and what is known about it so far?

Atherosclerosis and its complications are leading causes of death and disability in most western countries. In atherosclerosis, arteries are thickened and narrowed by fatty material and calcium. Narrowed arteries reduce blood flow and increase risks for heart attack, stroke, and other diseases. Doctors often advise patients to exercise regularly to prevent atherosclerosis. Surprisingly, few long-term studies show whether exercise slows progression of atherosclerosis.

Why did the researchers do this particular study?

To see whether consistent, long-term aerobic exercise compared with routine activity slows thickening of artery walls.

Who was studied?

140 middle-aged white men living in Finland.

How was the study done?

Men were randomly assigned to regular aerobic exercise or habitual activity. Aerobic exercise included walking, jogging, cross-country skiing, swimming, or cycling. Target exercise times were 45- to 60-minute sessions 5 times weekly. Men in the exercise group received heart rate monitors and kept an exercise diary. Men in the other group were not told to change their exercise patterns, and they did not keep diaries. Men were followed for 6 years. Each year, they took a bicycle exercise test to measure breathing fitness. They also had ultrasonography to measure the thickness of the walls of the arteries in the neck (carotid arteries). Experts who read these tests did not know which men had been exercising regularly. The researchers then compared groups to see whether those assigned to exercise had less thickening of the artery walls (atherosclerosis).

What did the researchers find?

At the start of the study, both groups had similar fitness and carotid artery wall thickness. Over time, the exercise group's fitness improved while the other group's fitness declined slightly. Over time, artery walls thickened to a similar extent in both groups. However, exercise slowed thickening of the artery wall in a subgroup of men who were not taking cholesterol-lowering medicines (statins).

What were the limitations of the study?

The number of participants was small. Only middle-aged men were studied.

What are the implications of the study?

Regular aerobic exercise might not slow thickening of artery walls, except in patients who do not take medicines that lower cholesterol levels.