Less “deep sleep” can be linked to a greater chance of developing neurodegenerative diseases such as dementia, according to a new scientific study.
The study refers to rapid eye movement (REM) sleep, the stage of the sleeping cycle where the body regenerates the most, associated with dreaming, faster breathing, and raised body temperature.
Researchers looked at 321 people with an average age of 67 in the USA. Their sleep cycles were measured over a 12 year period. During that time, 32 people were diagnosed with some form of dementia – 24 of which were deemed to have Alzheimer’s disease.
The people who developed dementia spent an average of 17 per cent of their sleep time in REM sleep, compared to 20 per cent for those who did not develop the disease.
The scientists concluded that for every one per cent reduction in REM sleep there was a nine per cent increase in the risk of dementia.
Commenting on the study, Dr James Pickett, Head of Research at Alzheimer’s Society, said: “There’s increasing evidence that disturbed sleep is a risk factor for dementia. This study found, by monitoring patterns of brain activity during sleep, that trouble with the REM stages of sleep may be linked to a small increased risk of the condition.
“Researchers found that only a small number of people on the study developed dementia and so we can’t draw any firm conclusions from this work alone. However, it does show the value of recording people’s sleep patterns in-depth to gain a more accurate idea of what aspect of sleep could contribute to risk, and that it is more complex than simply counting the hours we spend in bed.
“Over the next few years we should hope to see some answers to the novel questions about the role that sleep plays in dementia risk, including whether sleep disturbance is a contributing factor to dementia risk or is caused by the early stages of the condition. Studies can also start to test if correcting sleep abnormalities can reverse any increase in risk. There are things that we can all do to try and improve our sleep, such as avoiding alcohol, caffeine and smoking in the hours before bed and trying to establish more routine around bedtime.”