Lack of Sleep Linked to Alzheimer’s, Weight Gain

Two separate studies have found that sleep loss may put you at risk for weight gain and Alzheimer’s disease.

MONDAY, March 11, 2013 — Trouble sleeping might be a sign of early Alzheimer’s disease, according to a new study conducted by researchers at Washington University School of Medicine in St. Louis

The study, published in JAMA Neurology, is a follow-up to a 2012 animal study also conducted at Washington University, in which researchers concluded that mice lost approximately 25 percent of their sleep time as plaque — a sign of Alzheimer’s disease — began to develop in their brains.

Researchers believe that the emergence of Alzheimer’s plaques can disrupt sleep – and that lack of sleep also contributes to formation of more plaques.

“This link may provide us with an easily detectable sign of Alzheimer’s pathology,” said senior author David M. Holtzman, MD, in a press release. “As we start to treat people who have markers of early Alzheimer’s, changes in sleep in response to treatments may serve as an indicator of whether the new treatments are succeeding.”

Dr. Holtzman and his team recruited 145 volunteers ages 45 to 75, all of whom appeared to have normal cognitive functioning abilities. However, an analysis of spinal fluids for Alzheimer’s markers revealed that 32 participants had preclinical Alzheimer’s disease.

All volunteers were strapped with motion sensors while they slep to detemine to determine sleep quality. The amount of movement registered by the sensors was converted into a measure of sleep efficiency that indicates how much of a person’s time in bed was spent asleep.

The numbers revealed a 3.3 percent difference in sleep efficiency between those with preclinical Alzheimer’s disease (80.4 percent) and those without (83.7 percent). Researchers also found that people whose sleep efficiency rating was lower than 75 percent were more than five times as likely to have preclinical Alzheimer’s disease.

Scientists now hope to follow up this study by repeating the sleep and Alzheimer’s tests on younger participants with sleep disorders, rather than just trouble sleeping.

While there is definitely a link between the two, more research is needed to determine causation between lack of sleep and early Alzheimer’s. Until lack of sleep is deemed to be a cause of Alzheimer’s disease, patients that can’t sleep should not immediately assume they have an early form of the disease.

“We think this may help us get a better feel for the way this connection flows — does sleep loss drive Alzheimer’s, does Alzheimer’s lead to sleep loss, or is it a combination?” said first author Yo-El Ju, MD, in the press release. “That will help us determine whether we can change the course of disease with pharmaceuticals or other treatments.”

Less Sleep, More Weight

Poor sleep has once again been linked to weight gain, in a small new study from the University of Colorado, Boulder. Researchers there found that people who average five hours of sleep a night can gain nearly two pounds a week.

However, scientists don’t believe that the weight gain was directly caused by sleep loss. Rather, researchers feel that insufficient sleep can lead to dietary changes that promote weight gain.

“Just getting less sleep, by itself, is not going to lead to weight gain,” said Kenneth Wright, PhD, director of CU-Boulder’s Sleep and Chronobiology Laboratory in a press release. “But when people get insufficient sleep, it leads them to eat more than they actually need.”

This researchers evaluated 16 healthy young adults for about two weeks in a University of Colorado Hospital “sleep suite” designed to be a controlled environment for sleep monitoring.

After three days of sleeping up to nine hours and eating an average amount of calories, participants were split into two groups: One group slept nine hours a day over five days, while the other group slept only five hours a day. After the first five days, the groups switched schedules, and were observed for another workweek.

Despite having the same access to food, whichever group slept for approximately five hours ate 6 percent more calories on average. A large portion of these calories came from snacks — the total number of calories from snacks consumed by the lighter sleepers was higher than that of any single meal.

Wright hopes this research will lead to a better understanding of sleep and caloric intake. He has begun working on a study in which he hopes to learn not only what sleep-deprived people eat, but also when they eat.

“When people are sleep-restricted, our findings show they eat during their biological nighttime when internal physiology is not designed to be taking in food,” said Wright.

By Jeffrey Kopman