Researchers in the United States and United Kingdom have said struggling to get a good night’s sleep could be an early warning sign of dementia.

According to the researchers, people who go into REM sleep – the sleep phase responsible for dreaming – later in the night are more likely to develop dementia.

The study was published in the journal ‘Alzheimer’s & Dementia’. The REM phase, also known as rapid eye movement, is when the brain processes memories and emotions.

The research suggests that those who take longer to fall into this deep sleep phase may be experiencing an early symptom of Alzheimer’s disease, the research suggests.

A sleep expert has described the findings as “another important piece of the puzzle” in understanding how important sleep is for our brain. Dr Greg Elder, Associate Director, Northumbria Centre for Sleep Research, Northumbria University in the UK has extensively studied the relationship between sleep and dementia.

“This new study is really interesting because it doesn’t just focus on people with Alzheimer’s disease, and it shows that there is a link between how long it takes people to get to rapid eye movement sleep – not just our sleep duration – and relevant dementia biomarkers – not just how well we perform in clinical tests of our brain health, Dr Elder said.