Regular lie-ins are worse than getting too little sleep, study suggests

Having regular lie-ins is worse for the body than getting too little sleep, new research suggests.

Scientists have known for some time that not getting enough sleep increases the risk of a string of health complaints such as high blood pressure, heart disease, obesity and diabetes.

But a new review led by Keele University in Staffordshire, found that people who slept for an average of ten hours a night were 30 per cent more likely to die early than those who only slept for seven hours.

Current recommendations suggest that adults should sleep for eight hours a night and although the precise benefits of sleep are still unknown experts believe it gives the body a chance to repair cells and blood vessels, clear out waste and boost the immune system.

However it was generally thought that too little sleep was far worse than too much. But the new review of 74 studies involving three million people shows the opposite is true.

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The research found that a sleep duration of ten hours were 56 per cent more likely to suffer a stroke, at 49 per cent increased risk of dying from cardiovascular disease and a 44 per cent increase in coronary heart disease.

Lead researcher Dr Chun Shing Kwok, working with Professor Mamas Mamas at Keele University's Institute for Science and Technology in Medicine, said: “Sleep affects everyone.

“The amount and quality of our sleep is complex. There are cultural, social, psychological, behavioural, pathophysiological and environmental influences on our sleep such as the need to care for children or family members, irregular working shift patterns, physical or mental illness, and the 24-hour availability of commodities in modern society.

“This research began because we were interested to know if it was more harmful to sleep below or beyond the recommended sleep duration of seven to eight hours.”

The analysis suggests that excessive sleep patterns could be a marker of increased cardiovascular risk.

The results show that sleeping for longer than the recommended duration of seven or eight hours may be associated with a moderate degree of harm, compared to those who sleep for shorter durations.

“Our study has an important public health impact in that it shows that excessive sleep is a marker of elevated cardiovascular risk,” added Dr Kwok.

“Our findings have important implications as clinicians should have greater consideration for exploring sleep duration and quality during consultations.

“If excessive sleep patterns are found, particularly prolonged durations of eight hours or more, then clinicians should consider screening for adverse cardiovascular risk factors and obstructive sleep apnea, which is a serious sleep disorder that occurs when a person's breathing is interrupted during sleep.”

It is unclear why oversleeping is bad for health. Some studies have suggested that it changes the production of brain chemicals such as serotonin or dopamine which can lead to depression. Lying in the same position for too long can also weaken muscles, leading to back and joint pain. It could also cause circadian disruptions which stop the body from functioning correctly. 

However the researchers cautioned that they had not ruled out the possibility that underlying physical or mental health conditions could be triggering too much sleep. Many depressed people, for example, use sleep as a means of escape.

The study, which also involved researchers from the universities of Leeds, Manchester and East Anglia, was published in the Journal of the American Heart Association.

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