People with sleep apnea wake up tired in the morning, no matter how many hours they actually sleep. The condition causes them to briefly stop and restart breathing dozens or even hundreds of times a night. Even though such breathing interruptions often don’t awaken those with apnea, they prevent them from sinking into deep, refreshing sleep.
A new study puts a number on how dangerous such chronic tiredness can be, at least in regard to driving. For every eight additional breathing interruptions per hour, the odds of making a dangerous driving move such as speeding, braking hard or accelerating suddenly increase by 27%, according to a study by researchers at Washington University School of Medicine in St. Louis.
Older adults are more likely to develop sleep apnea. They also are more likely to be seriously injured or killed in a car accident. The findings, available online in the journal Sleep, suggest that screening older adults for sleep apnea and for treatment, if needed, may help older people continue driving safely for longer.
“The percentage of older adults with mild sleep apnea is 30% to 50%, but if such adults don’t have daytime sleepiness or other evidence of impairment, they may not come to medical attention,” said co-senior author Brendan Lucey, MD, an associate professor of neurology and director of Washington University’s Sleep Medicine Center. “However, these findings suggest that we might want a lower threshold to evaluate older adults for sleep apnea and track their breathing interruptions. If their conditions worsen by just eight interruptions an hour, that could have significant adverse effects on their driving and their risk of suffering serious injury.”
People 65 and over are the most responsible drivers on the road. They obey speed limits. They drive defensively. They avoid driving at night, in bad weather and in unfamiliar places. But the changes that often come with advancing age — such as deteriorating vision, slower reflexes and, yes, difficulty sleeping — can undermine even the safest habits.
Lucey teamed up with driving researcher Ganesh M. Babulal, PhD, OTD, an assistant professor of neurology and the paper’s co-senior author, to investigate the relationship between sleep apnea and risky driving behaviors. Participants were recruited from ongoing studies at Washington University’s Charles F. and Joanne Knight Alzheimer Disease Research Center (Knight ADRC).