Researchers in the United States determine the differences between sleep deficiency and sleepiness on the risk of a car crash, reports Medical News Bulletin.

Many people suffer from sleep deficiency, defined as an insufficient amount of sleep.  Possible causes for sleep deficiency include a habitually short sleep duration and sleep apnea. A symptom of sleep deficiency is excessive sleepiness, which in turn has been identified as a leading car crash risk. Only half of those who suffer from sleep apnea experience daytime sleepiness.

Are sleep deficient people more at risk of a car crash even without showing excessive sleepiness?
Researchers in the United States investigated whether sleep deficient people were more at risk of having a car crash, even if they did not show excessive sleepiness. The study involved questioning participants from the larger Sleep Heart Health Study (SHHS) from the American National Heart, Lung, and Blood Institute.