Turn up the intensity!

High Intensity Exercise Has Heart-Healthy Effect

By Paula RasichReviewed by Elizabeth Klodas, MD, FACC
January 5, 2009--Here’s another reason to follow through on that New Year’s resolution to up the intensity of your workout. According to a small study, intense physical activity increases blood flow through the arteries, even after a fatty meal.

In addition to boosting “good” HDL cholesterol, cutting “bad” LDLs, and lowering blood pressure, intense exercise benefits your heart by protecting the inner layer of blood vessel walls, called the endothelium, from getting stiff. Endothelial dysfunction---when blood vessel linings no longer widen to accommodate increased blood flow---sets the stage for atherosclerosis.

To investigate the effect of exercise and a high-fat meal on how well the inside of blood vessels function, a team of scientists from Norwegian University of Science and Technology in Trondheim, Norway and elsewhere, assigned eight healthy men to three trials. In the first, study volunteers engaged in one session of moderate-intensity activity (60 to 70% of maximal heart rate) 16 hours before eating a high-fat meal. In the second, participants did a high-intensity workout (85 to 95% of maximal heart rate) 16 hours before eating the same high-fat food. In the third, the men did not exercise, but consumed the high-fat meal.

Before and after each meal, tests measured levels of blood fats (cholesterol and triglycerides), antioxidants, and how well blood vessels in the arm dilated in response to stress. Fatty foods generally diminish our blood vessels’ ability to dilate effectively. Interestingly in this trial researchers discovered that high-intensity activity was associated with a 45% improvement in arm blood flow after the fatty meal, even though the exercise session occurred many hours earlier. Moderate-intensity activity increased blood flow by 20%, whereas no blood flow improvement was seen in the sedentary group.

The novel finding study authors say “was that the high-intensity exercise not only prevented the normal post high-fat meal reduction in endothelial function but, in fact, increased blood flow despite lipemia [higher levels of blood fats].” The protective effect of high-intensity exercise was also long lasting, suggesting a mechanism by which regular exercise reduces the risk of heart and vascular disease.

The study findings are published in the January 13, 2009 issue of the Journal of the American College of Cardiology.
Source:
Tyldum GA et al. Endothelial Dysfunction Induced by Post-Prandial Lipemia: Complete Protection Afforded by High-Intensity Aerobic Interval Exercise. The Journal of the American College of Cardiology, 2008.Back to Top

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