A new study has found a link between poor sleep quality caused by the length of time it takes to enter the REM sleep phase, and an increased risk of developing Alzheimer’s disease
New research has revealed a disturbing link between poor sleep quality and a heightened risk of developing Alzheimer’s disease.
The study found that individuals who struggle to enter the crucial REM sleep phase, where dreams occur and memories are processed, are more likely to experience cognitive decline. According to the findings, published in ‘Alzheimer’s and Dementia,’ delays in reaching REM sleep during the fourth 90-minute cycle of sleep can not only hinder memory formation but also elevate stress hormones.
Dr Yue Leng PhD, the lead author, said: “The delay in REM sleep disrupts the brain’s ability to consolidate memories by interfering with the process that contributes to learning and memory.”
Dr Leng, part of the team from UCSF Weill Institute for Neurosciences, added: “If it is insufficient or delayed, it may increase the stress hormone cortisol. This can impair the brain’s hippocampus, a critical structure for memory consolidation.”
A study was conducted at the China-Japan Friendship Hospital in Beijing, where researchers invited 128 individuals aged over 70 to stay overnight in their sleep clinic. A third of these participants had mild cognitive impairments, half were diagnosed with Alzheimer’s, and the rest had normal cognitive function.
Their brain activity was measured while they slept, including brainwaves, eye movements, breathing, and heart rates. Participants were divided into two groups based on how long it took them to reach the REM sleep stage, reports the Express.
Those who entered this crucial stage quicker took 98 minutes on average, whereas those with poorer quality sleep took over three hours (198 minutes). Most patients with Alzheimer’s fell into this latter group, which also tended to have higher levels of proteins associated with Alzheimer’s and other forms of dementia.
Specifically, those with delayed REM sleep had 16% higher levels of amyloid and 29% higher levels of tau than the other group. This research adds to the growing body of evidence that links sleep quality to dementia risk, which could inform further studies on the effect of sleep-promoting drugs on reducing this risk.
Dr Leng concluded that “Future research should study the effects of certain medications that influence sleep patterns, as these may modify disease progression.”
Breaking ground in the science of sleep, researchers have found a potential link between treatments for insomnia that encourage REM sleep and a decrease in tau and amyloid levels in the brain – giving rise to hope that sleep therapies might play a role in fending off dementia.
Neurologist Dr Dantao Peng, a senior co-author of the study, said: “This includes treating conditions like sleep apnea and avoiding heavy drinking, since both can interfere with a healthy sleep cycle.
“Patients taking certain antidepressants and sedatives that reduce REM sleep should discuss their concerns with their doctor, if they are worried about Alzheimer’s.”
