Washington: A new study has discovered that too much sleep can double up person’s death risk. The researchers have revealed that sleeping too much can also be harmful, as lack of sleep doubles a person’s death risk from heart disease.

The researchers group from the University of Warwick and University College London presented the findings to the British Sleep Society in Cambridge.

The study results that will be released in the journal ‘Sleep’ are based on a 17-year study of how sleeping patterns affected the death rate of 10,308 officials.

The study analyzed the sleep patterns of partakers aged between 35-55 at two different points in their lives -- 1985-88 and 1992-93 -- and then checked their death rates until 2004.

The scientists also studied the other possible factors including age, sex, marital status, employment grade, smoking status, physical activity, alcohol consumption, self-rated health, body mass index, blood pressure, cholesterol, and other possible physical ailments.

Once the group adjusted for these agents, they were capable of isolating the effect that changes in sleeping patterns over the period of 5-years had on death rates some 11 to 17 years later.

Those who slash their sleeping time from seven hours to five hours or less faced up a 1.7-fold increased risk in death from all causes, and twice the increased risk of death from a cardiovascular problem in particular by 2004.

Franceso Cappuccio, professor of cardiovascular medicine at the University of Warwick's medical school, said, “Fewer hours sleep and greater levels of sleep disturbance have become widespread in industrialised societies.”

He further said that individuals who showed an increase in sleep duration to eight hours or more a night were more than twice as likely to die as those who had not changed their habit, though predominantly from non-cardiovascular diseases.

“Short sleep has been shown to be a risk factor for weight gain, hypertension and Type 2 diabetes sometimes leading to mortality, but in contrast to the short sleep-mortality association it appears that no potential mechanisms by which long sleep could be associated with increased mortality have yet been investigated. Some candidate causes for this include depression, low socio-economic status and cancer-related fatigue,” said Professor Cappuccio.

“In terms of prevention, our findings indicate that consistently sleeping around 7 hours per night is optimal for health and a sustained reduction may predispose to ill-health,” he added.