Expecting an afternoon nap can reduce bloo...( BETHESDA Md. (Oct. 15 2007) Where d...)

BETHESDA, Md. (Oct. 15, 2007) Where does the benefit lie in an afternoon nap" Is it in the nap itself--or in the anticipation of taking a snooze" Researchers in the United Kingdom have found that the time just before you fall asleep is where beneficial cardiovascular changes take place.

This finding is part of a study entitled Acute Changes in Cardiovascular Function During the Onset Period of Daytime Sleep: Comparison to Lying Awake and Standing, found in the online edition of the Journal of Applied Physiology, published by The American Physiological Society. The study was conducted by Mohammad Zaregarizi, Ben Edwards, Keith George, Yvonne Harrison, Helen Jones and Greg Atkinson, of the Liverpool John Moores University in Liverpool, U.K.

Afternoon naps, or siestas, are practiced in many Mediterranean and Latin American countries such as Spain and Argentina. They are typically short naps or rest periods of no more than an hour that are taken in the afternoon.

While earlier studies on siestas have found that this practice may slightly increase the risk of heart attack, newer and more controlled studies have shown an inverse relationship between siesta taking and fatal heart attacks. In a recent epidemiological study of 23,000 people in Greece, those who regularly took siestas showed a 37% reduction in coronary mortality compared to those who never nap, while individuals who occasionally napped in the afternoon had a reduction of 12%.

Why do afternoon naps affect cardiovascular function" One reason could be changes in blood pressure. At night, our blood pressure and heart rate decreases as we sleep. Some researchers hypothesize that the lower blood pressure reduces strain on the heart and decreases the risk of a fatal heart attack.

Most studies have focused on cardiovascular behavior in nighttime sleeping. This study provides a detailed description of changes in cardiovascular fu
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