Sleeping less than 7.5 hours a day may raise the risk of heart disease in elderly people, especially those who have elevated blood pressure at night, a study in Japan has found.
Scientists monitored sleeping patterns of 1,255 elderly people with hypertension and of an average age of 70.4, and followed them for 50 months.
During the followup period, the researchers recorded 99 strokes, heart attacks and sudden cardiac deaths, and found more of them occurred among those who had less sleep.
"The group that had both shorter sleep duration plus the riser pattern (elevated blood pressure at night) had a 4.4 fold increase of cardiovascular disease compared with those with longer sleep duration," the researchers wrote in the latest issue of the Archives of Internal Medicine.
People are generally sleeping less in modern societies. But getting adequate sleep is essential to preventing problems such as obesity and diabetes as well as several risk factors for cardiovascular disease including sleep-disordered breathing and night-time hypertension.
"Shorter duration of sleep is a predictor of incident cardiovascular disease in older people with hypertension particularly when it occurs with elevated night-time blood pressure", wrote the researchers, led by Kazuo Eguchi at Jichi Medical University in Japan.
They also urged that elderly people with such symptoms to be monitored more closely.
Reuters