Excessive sleepiness can cause cognitive impairments and put individuals at a higher risk of motor vehicle crash. But the perception of impairment from excessive sleepiness quickly plateaus in individuals who are chronically sleep deprived, despite continued declines in performance.So individuals may be unaware of their degree of impairment from sleep deficiency, which raises the question of whether these individuals are at an increased risk of motor vehicle crash. A team of researchers from Brigham and Women’s Hospital (BWH) addressed this question and their results are published in BMC Medicine.
“We found that chronically sleep-deprived individuals don’t perceive themselves as being excessively sleepy and thus don’t perceive themselves as impaired,” says lead author Daniel J. Gottlieb, MD, MPH, associate physician in the Division of Sleep and Circadian Disorders at BWH, in a release. “This resulted in an increased risk of motor vehicle crashes in sleep-deprived individuals.”
The prospective study examined the relationship between motor vehicle crashes and two common causes of sleep deficiency—insufficient sleep duration and obstructive sleep apnea (OSA). The cohort in the study were participants in the Sleep Heart Health Study, a community-based study of the health consequences of sleep apnea, comprised of 1,745 men and 1,456 women between the ages of 40 and 89.
Severe OSA was associated with a 123% increased risk of motor vehicle crash, and mild to moderate sleep apnea was associated with a 13% increased risk of motor vehicle crash. These numbers were in comparison to those with no sleep apnea. Sleeping 6 hours per night was associated with a 33% increased crash risk, compared to sleeping 7 or 8 hours per night. Gottlieb adds that this increased risk of crash was independent of an individual’s self-reported sleepiness.
“To help reduce these crash risks we need to identify individuals with sleep apnea and ensure they are properly treated for their apnea. We also need to increase public awareness of the importance of a good night’s sleep to reduce the percentage of the population with insufficient sleep duration,” Gottlieb says. “Ultimately, we would like to be able to identify a biomarker for cognitive impairments due to excessive sleepiness.”
This study used data from the Sleep Heart Health Study which was supported by National Heart, Lung and Blood Institute.