Too much sleep is more dangerous than not enough

Sleeping more than nine hours or fewer than seven increases the risk of death, a study found. Photo / 123rf

Sleeping for too long is worse for your health than a lack of sleep, a new study has suggested.

Researchers found people who regularly sleep for fewer than seven hours per night or more than nine hours per night were increasing their risk of death.

The study revealed that those sleeping for fewer than seven hours were 14% more likely to die from any cause than those getting the optimal seven to eight hours of shut-eye.

But it also showed the increased risk of death rose to 34% among people who were regularly sleeping for nine hours or more per night.

Experts from the Semmelweis University in Budapest, Hungary, analysed data from more than 2.1 million participants across 79 separate international studies.

Men were at greater risk of death than women from sleeping too little, while women faced a greater risk than men from sleeping for too long each night, the research said.

The study found men who slept for less than seven hours a night had a 16% higher risk of death, and those who slept for eight hours or more had a 36% increased risk.

Meanwhile, women with short sleep durations had a 14% higher risk, and those sleeping for longer faced a 44% increased risk.

The researchers said the differences were likely because of hormonal, behavioural or cardiovascular differences between men and women.

‘A sleep epidemic’

Dr György Purebl, director of Semmelweis University’s Institute of Behavioural Sciences and co-author of the study said: “As a society, we are experiencing a sleep epidemic. Even though awareness has grown, our behaviour hasn’t changed much in the last decade.

“The constant exposure to blue light, pressure to remain available around the clock, and disruption of our natural biological rhythms continue to take a toll on our health.”

The authors of the study warned that sleep deprivation is a growing global health concern, with millions of people regularly sleeping too little because of work demands, exposure to digital screens, and stress.

Shift workers and those with irregular schedules are particularly affected, it said.

Chronic sleep loss is not only linked to premature death but also a range of health issues including obesity, diabetes, cardiovascular disease and a worsening immune system.

Sleep and strokes

In a second study, the Hungarian researchers looked at the impact of sleep duration on the risk of stroke and subsequent death.

They found that people sleeping for five to six hours per night had a 29% higher risk of stroke than those sleeping for seven to eight hours and were 12% more likely to die because of the stroke.

Those sleeping more than eight hours had a 46% higher risk of stroke and were 45% more likely to die from it.

Dr Balázs Győrffy, head of the Department of Bioinformatics at Semmelweis University, and senior author of both studies, said: “Stroke remains one of the leading causes of death and long-term disability worldwide”.

“Identifying modifiable risk factors like sleep can offer powerful public health benefits.

“Our findings make it clear that sleep duration should be considered in stroke prevention strategies to reduce the burden on healthcare systems and improve population health.”