Normal aging causes a decline in cardiac performance. Before it pumps blood to the rest of the body, the heart's left ventricle fills with blood in a two-phase process. The first phase, which fills the ventricle in healthy hearts to about 80 percent capacity, is a passive, suction-mediated mechanism called early ventricular filling. The second phase is more active because the heart's atrium contracts to completely fill the ventricle with blood. As we get older, less blood gathers during the passive, diastolic phase, so the atrium has to work harder to increase the amount of blood it forces into the ventricle.
"This decline in diastolic function is a marker of primary aging," Fontana says. "Diastolic function declines in most people as they get older, but in this study we found that diastolic function in calorie-restricted people resembled diastolic function in individuals about 15 years younger." It may even be possible that eating a very low-calorie, nutrient dense diet reverses declines in diastolic function. People in the study averaged only six years on the diet, but their hearts looked 15 years younger. So Fontana says it's possible that the diet has a rejuvenating effect.
He notes that most study subjects had parents, grandparents or siblings who suffered heart attacks or strokes, making it unlikely that their genetic makeup is a contributor to the unusual healthiness of their hearts. In the case of one subject, bo
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Contact: Jim Dryden
jdryden@wustl.edu
314-286-0110
Washington University School of Medicine
12-Jan-2006