Sleep drugs cause falls and impair thinking
Adults on sleep medications are at high risk for nighttime falls and potential injury, according to a new study published last week in the Journal of the American Geriatric Society.
Researchers of the University of Colorado at Boulder recruited 25 healthy adults and found 58 percent of the older adults and 27 percent of the young adults who took zolpidem, a hypnotic and sleep-inducing drug, had a significant loss of balance even after being awake for two hours.
To measure balance, researchers used a technique called “tandem walk” in which place one foot in front of the other with a normal step length on a 16-foot-long, six-inch-wide beam on the floor. None of the participants stepped off the beam in 10 previous tests without taking the drug, indicating no loss of balance. Stabilizing assistance was offered to the subjects during the trials, according to lead study author Professor Kenneth Wright.
"The balance impairments of older adults taking zolpidem were clinically significant and the cognitive impairments were more than twice as large compared to the same older adults taking placebos," said Wright, "This suggests to us that sleep medication produces significant safety risks."
In addition to the balance problems, scientists also found out that waking up after two hours of sleep after taking zolpidem enhances sleep inertia, or grogginess, a state that temporarily impairs working memory.
The effect of sleep inertia has previously been shown to cause impairment of cognition, even without sleep medication. But when the study subjects took zolpidem rather than a placebo, the cognitive impairments doubled.
One unexpected finding focused on young people taking placebos who appeared to be cognitively affected by sleep inertia than older adults.
The CU-Boulder scientists also measure balance and cognition in older adults who did not take sleep drugs and were kept awake for two hours past their normal bedtime.
The result, 25 percent of those subjects failed the tandem walking balance test, which is consistent with what is seen in people with insomnia.
"Just having insomnia itself increases your risk of falls, even without sleep medication," Wright said.
In addition, the cognitive impairments may impact decision-making, reaction to the emergency situations and caring for sick children, said Wright.
The reason why zolpidem affected older people more than younger adults is partly because both groups were given five milligram doses on study night. The normal dose for older adults to treat insomnia is 5 milligrams but for younger adults is 10 milligrams.
The study results showing both the sleep medications and sleep inertia may cause significant impairment have great implications to public health. Falls have injured millions annually and cause 300,000 fatalities worldwide.
Stephen Lau and editing by Aimee Keenan-Greene