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New research presented at the European Society of Cardiology (ESC) Congress 2018 has suggested that around six to eight hours sleep a night could be ideal for maintaining good health, with more or less shut-eye appearing to have a negative effect on well-being.

In the first of three studies presented at the event, researchers at the Onassis Cardiac Surgery Centre, Greece, carried out a meta-analysis to investigate the relationship between sleep duration and risk of cardiovascular disease (CVD), looking at 11 studies with a total of 1,000,541 adults without CVD.

They found that compared to those who slept six to eight hours a night, short sleepers who slept less than six hours per night had an 11 percent increased risk of developing or dying from coronary artery disease or stroke during an average follow-up of 9.3 years.

For long sleepers, defined as those who slept more than eight hours per night, this number rose to a 33 percent increased risk.

“Our findings suggest that too much or too little sleep may be bad for the heart,” said study author Dr. Epameinondas Fountas. “More research is needed to clarify exactly why, but we do know that sleep influences biological processes like glucose metabolism, blood pressure and inflammation, all of which have an impact on cardiovascular disease.”

“Having the odd short night or lie-in is unlikely to be detrimental to health, but evidence is accumulating that prolonged nightly sleep deprivation or excessive sleeping should be avoided,” added Dr. Fountas. “Getting the right amount of sleep is an important part of a healthy lifestyle.”

Research from the Spanish National Centre for Cardiovascular Research (CNIC) in Madrid, which was also presented at the congress, adds to the evidence that too little sleep may have a negative effect on health.

After recording the sleep of 3,974 healthy middle-aged adults over a seven-day period, the researchers found that those who sleep less than six hours a night or wake up several times in the night have an increased risk of asymptomatic atherosclerosis, which hardens and narrows the arteries, than those who sleep seven to eight hours a night or wake up less often.

Those who had short or disrupted sleep were also more likely to have metabolic syndrome, a collection of conditions including high blood sugar, high blood pressure and obesity, which can increase the risk of heart disease, stroke and diabetes.

Findings presented by the University of Gothenburg, Sweden also found that middle-aged men who slept less than five hours a night had twice the risk of a major cardiovascular event during the study’s 21-year follow-up than men who sleep seven to eight hours.

In addition, high blood pressure, diabetes, obesity, smoking, low physical activity and poor sleep quality were also more common in men who slept five or less per night compared to those who got seven to eight hours.

The ESC Congress 2018 takes place Saturday, Aug. 25 through Wednesday, Aug. 29 in Munich, Germany. JB

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