A team from the Onassis Cardiac Surgery Centre in Athens, Greece, evaluated the impact of sleep duration on cardiovascular health by performing a meta-analysis of 11 prospective studies published within the last 5 years that included 1,000,541 adults with no known CVD.
The results, presented by Dr E Fountas, revealed that people who had either a short (<6 hours) or long (>8 hours) sleep duration were at significantly greater risk of CVD or death compared with a reference group who slept for 6–8 hours per night. The authors found no evidence of publication bias or significant heterogeneity, although moderate heterogeneity was noted in the analysis of short sleep duration, which did not appear to influence the results of the meta-analysis.
Fountas says, “Too little or too much sleep is bad news for the CV system. We found that sleeping for too long was potentially worse than sleeping too little, with a 32% greater relative risk of morbidity and mortality from stroke, coronary heart disease or CVD compared with the reference sleep duration. Short sleep duration increased the relative risk by 11%.” He adds, “Either way, both too little and too much sleep is significantly linked to CV risk.”
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Emily McGrath, senior cardiac nurse at the British Heart Foundation, said in a report in The Guardian: “When it comes to our heart and circulatory health, this large study suggests that there may be a sweet spot between getting too much and getting too little sleep.
“This research needn’t trigger alarm bells for those of us partial to a sleepless night or a weekend lie-in. However, if you regularly struggle with your sleep, it’s an important reminder to speak to your GP.
“As well as having a negative impact on your quality of life, a lack of sleep could also be contributing to heart problems further down the line.”