A new study finds that sleeping less than 6 hours or more than 8 hours a night puts a person at higher risk for various heart conditions. Sleeping too little means a higher prevalence of heart attacks, stroke, and congestive heart failure, while too much sleep is associated with angina and coronary artery disease (vasoconstriction).
Over 300 subjects above the age of 45 throughout the U.S participated in research led by Dr. Rohit Arora, chairman of cardiology at the Chicago Medical School. They found that people who slept more than 8 hours a night were twice as likely to have angina or chest pain and 1.1 times as likely to have coronary artery disease than people who slept an average of 8 hours a night. Subjects who slept too little were twice as likely to have a stroke or heart attack and 1.6 times as likely to have congestive heart failure. Even when age, sex, blood cholesterol, obesity, family history and smoking were accounted for these numbers remained significant. This stresses the importance that doctors ask heart patients extensively about their sleeping habits.
Why sleep effects heart health is still unclear. While the study is consistent with others that found a relationship between sleep quality and duration and cardiovascular health, it did not prove a cause and effect relationship. Other research has linked sleeping habits to diabetes, glucose intolerance, blood pressure, resting heart rate, hyperactive nervous system, and stress hormones.
From 1984 to 2000, the National Healthy Interview Survey found 6 percent of adults in the US sleep 6 hours or less a night. Although an observational study cannot prove cause and effect, there are possible mechanisms through which getting too little sleep may worsen cardiovascular health.