Safety tips about toys, candles, electric lights and drunk-driving are important messages during the holiday season. But warnings about the dangers of driving while tired (DWT) can get lost in the holiday crowd of public service announcements.
Naysayers could argue that DWT statistics are far less significant than drunk-driving casualties, with alcohol-related collisions [1]leading to more than 10,000 deaths in 2010 and annual costs of $37 billion.
But DWT is a real threat, says Erick Palma, M.D., [2] director of the Sleep Diagnostic Center at Mariners Hospital [3]. What’s more, in some cases, a drowsy driver represents the same threat as a drunk driver based on the level of impairment, an Australian research team documented.
In the U.S., the National Highway Traffic Safety Administration conservatively estimates that driver fatigue leads to:
- 100,000 crashes reported to police every year.
- 1,550 deaths and 71,000 injuries.
- $12.5 billion in losses.
Those figures are low-ball estimates because it can be difficult to identify the true cause of an accident, government officials say. A team of international experts has estimated that 10 to 30 percent of road collisions are due to drowsy drivers.
Dr. Palma, an expert on sleep disorders, offers answers to key questions.
What kind of threat do drowsy drivers represent?
Eye-opening data emerged from a Sleep in America poll [4], which was conducted by the National Sleep Foundation:
- Approximately 168 million, or 60 percent of adult drivers, reported driving while drowsy.
- About 37 percent (103 million) confessed to falling asleep while driving.
- Of those who snoozed at the wheel, 13 percent said that they nod off once a month — at a minimum.
- Roughly 11 million drivers admitted that their dozing or fatigue has caused a collision or a near accident.
What are the mechanics of driving while tired?
Excessive sleepiness takes a heavy toll on your reflexes, which become slower. You could lose or diminish your ability to respond properly to a red light or sudden road hazards. With dulled reflexes, you may not respond correctly when another car cuts you off in heavy traffic. Impaired by fatigue, you could miss exits, traffic signs or warning lights.
“In those situations, you could be a danger to yourself or others when you drive while tired,” Dr. Palma says.
Is excessive sleepiness linked to stress or an overload of holiday chores?
“Whatever does not let you sleep well could contribute to a reduction in your driving skills,” Dr. Palma says.
Your fatigue may be a secondary symptom of a health problem, including obstructive sleep apnea, restless leg syndrome or narcolepsy [3]. Chronic pain or asthma may lead to sleepless nights, which in turn causes extreme daytime fatigue. And of course, different medications can make you drowsy.
And there are other common factors. A student cramming all night for an exam may have a chronic sleep deficit, which in turn creates a greater danger when the student drives.
What other groups face increased risk?
Young men, parents and late-shift workers are more likely to have sleep-related crashes, according to the National Sleep Foundation. About 71 percent of drivers under age 30, drive while drowsy, compared to 52 percent of drivers ages 30-64, and 19 percent of those 65 and older. And men are nearly twice as likely to doze while driving.
Sleeplessness can be an occupational hazard for some workers, including commercial drivers and night-shift workers.
“People with undiagnosed sleep disorders, such as sleep apnea and acute insomnia, are also at greater risk for fall-asleep crashes,” according to a report from the National Sleep Foundation.
What about a sleep study?
“If you are excessively sleepy, there are specific sleep tests to figure out a reason,” Dr. Palma says.
An overnight sleep study can help determine if you suffer from a chronic problem such as sleep apnea. There are also daytime sleep studies to measure your degree of daytime wakefulness.
How much sleep should we get each night?
Adults should aim for seven to nine hours of sleep each night. Teens and some young adults should get 8.5 to 9.5 hours of nightly rest.
“Adequate sleep is not a luxury; it’s the foundation of good health,” Dr. Palma says. “Just like we need healthy meals, we also need healthy amounts of nightly sleep to protect our bodies.”