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Exercise helps heart, work strain hurts it: study

Last Updated: 2003-05-28 9:49:02 -0400 (Reuters Health)

NEW YORK (Reuters Health) - A new German study offers more evidence that leisure-time exercise helps ward off heart disease -- but heavy physical strain at work might promote it, researchers found.

The reason for the second finding is unclear, the study authors note, but other investigators have reached similar conclusions.

"The different characteristics of physical activity associated with work and leisure-time physical activity might be one explanation for the opposite relations with (heart disease) risk," they write in the current issue of the Archives of Internal Medicine.

Physical strain on the job, they note, "is probably long-lasting and mainly static," while exercise on one's own time is "mainly short-lasting and dynamic in nature."

The study involved 312 people ages 40 to 68 with heart disease who were compared with another 479 similarly aged people with healthy hearts. All were asked about leisure-time physical activity during summer and winter and any physical strain at work.

Overall, people with heart disease reported less leisure-time exercise and more physical strain on the job than those with healthy hearts, report Dr. Wolfgang Koenig, of the University of Ulm Medical Center, and colleagues.

Moreover, the researchers found, as leisure-time exercise increased, the risk of heart disease decreased. For example, exercising more than two hours a week in the summer was associated with a 61 percent lower risk of heart disease when compared with not exercising at all.

In contrast, as physical strain at work increased, so did the risk of heart disease, according to the report. Heavy physical strain on the job was associated with almost a five-fold greater risk of heart disease when compared with no strain at all.

However, biking or walking during the workday were linked to a lower risk of heart disease.

Blood tests of the study participants revealed that those who exercised during leisure time had lower levels of inflammatory markers such as C-reactive protein that are believed to contribute to hardening of the arteries.

This finding provides more support to the notion that exercise helps the heart by reducing inflammation, the researchers note.

Copyright 2002 Reuters.