HealthDay News/Dr. Tango--About 60% of the protection exercise offers women against heart disease and stroke comes from its effect on a few specific risk factors, claims a study in the journal Circulation.
Researchers assessed cardiovascular risk factors and exercise levels in more than 27,000 women between the ages of 45 and 90 (with an average age of 55) enrolled in the Women's Health Study. They were evaluated and observed by doctors for more than 11 years. 
Scientists concluded that women who exercised the most were 40% less likely to suffer a heart attack or stroke than women who did the least amount of exercise.
"Regular physical activity is extremely beneficial in preventing heart attack and stroke," said Dr. Samia Mora, lead author and instructor of medicine at Harvard Medical School in the divisions of cardiovascular and preventive medicine at Brigham and Women's Hospital in Boston, in a prepared statement.
"We found that even the slightest change in risk factors for heart disease and stroke, especially those related to inflammation/hemostasis and blood pressure, can have a profound impact on preventing clinical events. This study is the first to examine the importance of a variety of well-known risk factors in order to explain how physical activity prevents heart disease and stroke," affirmed Mora.
The Harvard team found that exercise-related changes in inflammatory and hemostatic biomarkers (fibrinogen, C-reactive protein and intracellular adhesion molecule-1) had the greatest impact, lowering heart attack and stroke risk by 33%.
"Inflammatory and hemostatic factors as a group have overlapping functions and roles and, in our study, had the biggest effect on mediating exercise-related cardio protection, more so than blood pressure or body weight," explained Mora.
The second most important improvement due to exercise was in blood pressure (a risk reduction of 27%) followed by lipids (blood fats), body mass index, glucose abnormalities, kidney function and homocysteine.
Due to a lack of clinical evidence, the American Heart Association doesn't recognize inflammatory and hemostatic biomarkers as risk factors for evaluating cardiovascular disease.
More information can be found on the American Academy of Family Physicians website.
SOURCE: American Heart Association, news release, Oct. 22, 2007 © Author rights 2007, ScoutNews, LLC
