Research conducted by the University of Maryland Medical Center found in 2009 that laughing could help protect against heart attacks.

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Laughter and a sense of humor may also protect against heart attacks by helping prevent heart disease, according to cardiologists at the University of Maryland Medical Center.

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Other trial sites along with the University of Maryland Medical Center are Baylor College of Medicine, Cincinnati Children's Hospital Medical Center, Emory University, Saint Louis University, Seattle Group Health Cooperative, the University of Iowa, and Vanderbilt University.

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