Your dreams can tell you if you are at greater risk for dementia

People who take longer to reach the dreaming part of their sleep cycle are more likely to develop dementia, a new study suggests.

Taking longer to enter the dream stage — known as rapid eye movement, or REM — can disrupt the ability to consolidate memories and interfere with emotion regulation, scientists say.

Recent studies have shown that the quality and quantity of sleep we get can affect the risk of developing Alzheimer’s disease.

Now, new research suggests that people who take “longer” to start REM may experience an early symptom of the disease.

The researchers explained that REM follows three stages of non-REM sleep, each deeper than the last.

The four stages take 90 minutes or more to complete, depending on age, and a person can cycle them four or five times in a typical night. Older people take longer to reach REM.

During REM sleep, the brain processes memories, especially those that are emotionally charged, and places them in long-term storage.

“The delay in REM sleep disrupts the brain’s ability to consolidate memories by interfering with the process that contributes to learning and memory,” said study co-author Professor Yue Leng, from the University of California, San Francisco.

“If it’s insufficient or delayed, it can increase the stress hormone cortisol. This can damage the brain’s hippocampus, a critical structure for memory consolidation.”

The researchers followed 128 people with an average age of 70 from the neurological unit of the China-Japan Friendship Hospital in Beijing. Half had Alzheimer’s, and about a third had mild cognitive impairment, a common precursor to Alzheimer’s.

Study participants slept overnight in the clinic so researchers could measure their brain wave activity, eye movement, heart rate and breathing.

Fitness trackers can capture some of this information, but it is less accurate.

The researchers divided the participants into early and late REM sleep.

On average, the early group reached REM less than 98 minutes after falling asleep, while the late group reached it more than 193 minutes after falling asleep.

Those with Alzheimer’s were more likely to have delayed REM sleep, according to findings published in Alzheimer’s and Dementia: The Journal of the Alzheimer’s Association.

They also tended to have higher levels of two toxic proteins, amyloid and tau, found in people with the condition.

Those with late REM sleep had 16% more amyloid and 29% more tau than those with early REM sleep. They also had 39% less of a healthy protein called brain-derived neurotrophic factor (BDNF), which declines in Alzheimer’s.

“Future research should study the effects of certain medications that affect sleep patterns, as these may modify disease progression,” Leng said.

She added that melatonin can increase REM sleep, and studies in mice have shown that it decreases the accumulation of tau and amyloid.

Other medications that treat insomnia by blocking a chemical that suppresses REM sleep have also been shown to decrease tau and amyloid.

People who are concerned about their Alzheimer’s risk should practice healthy sleep habits that ease the transition from light sleep to REM sleep, according to the research team.

“This includes treating conditions such as sleep apnea and avoiding heavy drinking, as both can interfere with a healthy sleep cycle,” added study co-author Dr Dantao Peng, of the Department of Neurology at China-Friendly Hospital. Japan in Beijing.

“Patients taking certain antidepressants and sedatives that reduce REM sleep should discuss their concerns with their doctor if they are concerned about Alzheimer’s.”