Getting just a few hours of sleep a night leads to a higher risk of chronic illness

UK-based researchers conducted a large follow-up study examining the effects of variations in sleep duration.

It turns out that those who only sleep a few hours a night (5 hours or less) are more likely to develop one or more chronic illnesses later in life.

The link between sleep deprivation and various illnesses, such as diabetes, for example, has already been made in the past. However, it was not yet known that the effect was so significant.

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The team analyzed the data from nearly 8000 people over a period of 25 years. They looked at the association between participants' sleep duration, mortality, and whether they had been diagnosed with two or more chronic conditions (multimorbidity).

It was found that those that are 50 or older and sleep for five hours or less per night have a 30% to 40% higher risk of chronic diseases such as diabetes, cancer, depression, liver disease, and dementia compared to peers that sleep 7 to 8 hours per night. 

The team also observed that sleeping 5 hours or less per night led to a 25% increase in mortality over the 25 years of follow-up. The scientists linked this steep increase to the aforementioned heightened risk of chronic diseases. 

Sleeping 9 hours or more

The scientists also examined if getting a long night's sleep (9 hours or more) also had an adverse impact, as some suggest. However, long nights of sleep at age 50 did not appear to be significantly associated with multimorbidity in healthy individuals.

Nonetheless, sleeping 9 hours or more per night was linked to a 35% higher risk of contracting another illness if a participant had an existing chronic condition. According to the researchers, this may result from underlying medical issues that affect sleep.

Due to the nature of self-reported data on sleep, it is likely to be subject to reporting bias. However, the findings were confirmed by the data from 4,000 people whose sleep was measured by electronic devices,

The results of the study are published in the peer-reviewed science journal PLoS Medicine as listed below. Be sure to check it out if you are interested in more underlying details of the research. 

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