People who do not get enough sleep are more than twice as likely to die of heart disease, according to a large British study released Monday.

    Although the reasons are unclear, researchers said lack of sleep appeared to be linked to increased blood pressure, which is known to raise the risk of heart attacks and stroke.

    A 17-year analysis of 10,000 government workers showed those who cut their sleep from seven hours a night to five or less faced a 1.7-fold increased risk of death from all causes and more than double the risk of cardiovascular death.

    The findings highlight a danger in busy modern lifestyles, Francesco Cappuccio, professor of cardiovascular medicine at the University of Warwick's medical school, told the annual conference of the British Sleep Society in Cambridge.

    "A third of the population of the UK and over 40 percent in the US regularly sleep less than five hours a night, so it is not a trivial problem," he told reporters.

    Previous research has highlighted the potential health risks of shift work and disrupted sleep. But the study by Cappuccio and colleagues, which was supported by British government and US funding, is the first to link duration of sleep and mortality rates.

    The study looked at sleep patterns of participants aged 35-55 at two points in their lives - 1985-88 and 1992-93 - and then tracked their mortality rates until 2004.

    The results were adjusted to take account of other possible risk factors such as initial age, sex, smoking and alcohol consumption, body mass index, blood pressure and cholesterol.

    Cappuccio said it was possible that longer sleeping could be related to other health problems such as depression or cancer-related fatigue.

    "In terms of prevention, our findings indicate that consistently sleeping around seven hours per night is optimal for health," he said.

    目前其中的原因尚不清楚，但研究人員稱，睡眠不足會導致血壓升高，從而增大患心臟病和中風的風險。

    一項針對1萬名政府職員、長達17年的跟蹤調查表明，每晚睡眠時間從七個小時減少到五個小時或更少的人因各種原因而死亡的幾率是睡眠正常者的1.7倍，而且死于心血管疾病的風險也增加了1倍多。

    沃里克大學醫學院的心血管藥物學教授弗朗西斯哥•卡普西奧在英國睡眠學會在劍橋召開的一年一度的研討會上說，這一研究成果揭示了忙碌的現代生活中潛在的危險。

    他在接受記者采訪時說：“三分之一的英國人以及超過40%的美國人每晚的睡眠時間常常達不到五個小時，所以這個問題不可小視。”

    此前有調查發現輪班及睡眠中斷會對健康產生潛在威脅。但卡普西奧及其同事的這項調查則首次揭示了睡眠時間長短與死亡率之間的關系。該調查由英國政府和美國基金提供資助。

    該調查對年齡在35歲至55歲之間的人在1985年至1988年以及1992年至1993年兩個階段的睡眠模式進行了探究，并對這一人群截至2004年的死亡率進行了追蹤。

    調查還考慮到了調查對象的初始年齡、性別、是否吸煙喝酒、體重指數、血壓及膽固醇指標等其它可能的風險因素。

    卡普西奧說，睡眠時間過長也可能導致如抑郁癥及癌因性疲乏等其它健康問題。

    他說：“就預防而言，我們的研究結果表明，每晚睡眠時間持續保持在七小時左右最益于身體健康。”