Coffee not so good before exercise
14 January 2006
by Richard
Conan-Davies
|
Two cups of coffee reduces the body's ability to boost blood flow to heart muscle in response to exercise. The effect was even stronger when the people were in a chamber simulating high altitude. This is according to s study led by Dr. Philipp Kaufmann of the University Hospital Zurich, Switzerland. Dr Kaufmann explained that "Whenever we do a physical exercise, myocardial blood flow has to increase in order to match the increased need of oxygen. We found that caffeine may adversely affect this mechanism. It partly blunts the needed increase in flow," Although this study included only 18 participants, the researchers said that the differences they saw were large enough for them to be confident that the effect of caffeine on heart muscle blood flow is real. They pointed out that longer studies of people with heart disease will be needed in order to understand whether the blood flow effects have important health consequences. |
Dr. Kaufmann explained that caffeine may block certain receptors in the walls of blood vessels, interfering with the normal process of signals to blood vessels to dilate in response to the demands of physical activity. As reported in the Jan. 17, 2006, issue of the Journal of the American College of Cardiology. |
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