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08-02-2011 | Cardiology | Article

Lack of sleep may raise CV disease risk


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MedWire News: The results of a large meta-analysis indicate that individuals who routinely sleep for less than 6 hours per night may have an increased risk for stroke and coronary heart disease (CHD)-related mortality.

Speaking to MedWire News, lead author Francesco Cappuccio from the University of Warwick, UK, explained: "In people of all ages, we found that between 6 to 8 hours of sleep per night on a regular basis does not seem to be associated with poor cardiovascular (CV) health in the long term.

"But there is a very clear threshold below which the risk rises sharply, and that is at 5 hours or less."

He remarked: "We feel that society is pushing people to squeeze more and more into their lives. Ideally we should spend one third of our lives asleep... sleep is a functional activity that should not be regarded as a waste of time."

The results, published in the European Heart Journal, also show an association between habitual long sleep (more than 8 hours per night) and increased CV risk. However, Cappuccio and team explain that this finding most likely reflects the tendency for fatigue to feature as a symptom in the early stages of chronic conditions, such as depression, which are known risk factors for CV disease.

The 15-study meta-analysis involved 474,684 healthy participants (aged 30 to 85 years) from eight different countries (UK, USA, Japan, Israel, Germany, Singapore, Sweden, and Taiwan).

All participants used questionnaires to self-report their sleep duration at baseline. Over a follow-up period of 7 to 25 years 4169 CHD events and 3478 strokes occurred.

The team found that individuals with routinely short sleep, defined as less than 6 hours per night, had a 48% greater risk for developing or dying from CHD and a 15% greater risk for stroke compared with those with a regular sleep duration of 6 to 8 hours (intermediate sleep; p<0.0001, p=0.047, respectively).

Similarly, individuals who routinely slept for more than 8 hours had a 38% and 65% higher risk for developing or dying from CHD and stroke, respectively, compared with those with intermediate sleep (p=0.0005, p<0.0001, respectively).

"By ensuring you have about seven hours sleep a night, you are protecting your future health," said Cappuccio.

Indeed, he added that sleep should be viewed as a modifiable CV disease risk factor that physicians should place more emphasis on.

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Lauretta Ihonor

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