The recent study, published in the journal Neurology and led by Matthew Pase, PhD, of the Swinburne University of Technology in Melbourne, Australia, analyzed data from the large, ongoing Framingham Heart Study (FHS). They focused on a subset of FHS participants who had taken part in the Sleep Heart Health Study for three years between 1995 and 1998. At the time, the participants were at least 60 years old, and half of them were male. Their sleep stages had been tracked with home-based sleep studies, which record brain waves and physiological changes to determine sleep cycles and different stages of sleep. The researchers were mostly interested in the rapid eye movement (REM) sleeping stage, which is when most of our dreaming occurs. This stage makes up around 20 percent of an adult’s night’s sleep, and begins roughly 80 to 100 minutes after first falling asleep. Along with dreams come an increased heart rate, quicker breathing, and a boost of blood flow to the genitals.
The team tracked 19 years of sleep data on the patients, and also checked for signs of dementia. During this follow-up period, Dr. Pase and his team recorded 32 diagnoses of dementia, 24 of which were caused by Alzheimer’s disease. The people with a dementia diagnosis spent, on average, 17 percent of their sleep in REM. People without dementia spent 20 percent on average.
But do fewer dreams equal a higher risk of dementia? Or could it be that dementia suppresses dreaming? To tease out an answer, the researchers made adjustments to the data by eliminating people from the findings who were at elevated risk of dementia or had been diagnosed in the first few years of the study. Then they re-ran the numbers and discovered a strong correlation between low-REM sleep—or taking longer to reach the dream state—and an elevated risk of dementia. For every percentage point that REM sleep decreased, the researchers found a 9 percent increase in the risk of dementia. (Did you know these habits are risk factors for dementia?)
“In our study, the association between lower REM sleep and dementia was not explained by those with cognitive impairment at baseline or by those who converted to dementia within the first three years, [which] suggests that reduced REM is not simply a consequence of early dementia,” Dr. Pase told Medical News Today.
While Dr. Pase admits he doesn’t have the exact answers to explain the findings, he does suggest a few possible hypotheses: Stress or anxiety can interfere with sleep and reduce the opportunities for dreaming; so can breathing conditions like sleep apnea, which prevent sleepers from ever reaching deep sleep. On the other hand, dreaming regularly may help keep the mind running smoothly by maintaining brain integrity, he says.
If you’re worried you’re not getting enough REM sleep, there are steps you can take. According to Andrew Weil, MD, “REM sleep in particular can be negatively affected by a number of factors including drinking caffeinated beverages during the day, and taking medications such as certain diet pills and decongestants. In addition, most sleep aids—both prescription and over-the-counter—suppress REM sleep, as do many antidepressant drugs and the early morning nicotine withdrawal that wakes heavy smokers prematurely.”
Weil also warns against having an alcoholic drink to overcome insomnia. While this may help you fall into a light sleep, it robs you of precious REM time. Temperature and comfort are also factors, so if your mattress is past its prime, you might want to invest in a new one. Here are secrets from sleep doctors on how to sleep better—and hopefully dream longer.