Physical Fitness and Carotid Atherosclerosis in Middle-Aged Men

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The summary below is from the full report titled "Cardiorespiratory Fitness and the Progression of Carotid Atherosclerosis in Middle-Aged Men." It is in the 2 January 2001 issue of Annals of Internal Medicine (volume 134, pages 12-20). The authors are TA Lakka, JA Laukkanen, R Rauramaa, R Salonen, H-M Lakka, GA Kaplan, and JT Salonen.

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

Atherosclerosis is a condition in which blockages form in blood vessels. Atherosclerosis leads to heart attacks when it involves the blood vessels of the heart (coronary arteries) and to strokes when it involves the blood vessels leading to the brain (carotid arteries). People who are physically fit are known to be less likely to have atherosclerosis-related events such as heart attacks and strokes. However, it is not known exactly how physical fitness protects people from strokes or whether physical activity will actually slow the progression of atherosclerosis in its early stages.

Why did the researchers do this particular study?

To find out whether physical fitness is associated with less progression of early atherosclerosis in the carotid arteries.

Who was studied?

The study included 854 men 42 to 60 years of age who lived in Finland. The men were participating in a large study of heart disease.

How was the study done?

The researchers examined the men and asked them detailed questions about their level of physical activity. The men also completed a special test that measured how physically fit they were by monitoring them during exercise. The researchers did ultrasound tests, which show detailed images of the men's carotid arteries, both at the start of the study and again 4 years later. These images made it possible to measure the amount of narrowing from atherosclerosis. The researchers tested the relationship between the amount of atherosclerosis that developed over the 4 years and the men's physical fitness levels.

What did the researchers find?

The increase in carotid artery atherosclerosis was greatest in men with the worst physical fitness and least in the men with the best physical fitness. This association remained even after the researchers accounted for other known atherosclerosis risk factors.

What were the limitations of the study?

This study included only men 42 to 60 years of age. It is not known if the same results would occur in women or in people of other ages. The researchers did not follow the men long enough to see if the increases in carotid artery atherosclerosis actually led to strokes. In addition, the researchers measured physical fitness only at the beginning of the study, but many people change their activity levels over time.

What are the implications of the study?

This study suggests that men 42 to 60 years of age who are physically fit are less likely to have worsening carotid atherosclerosis over time.