The engineer at the helm of the Metro North train that derailed on Sunday in the Bronx may have fallen asleep[1] right before the train went off the tracks, according to news reports. While William Rockefeller was reportedly "well-rested," the New York Daily News did point out that he recently had a schedule change[2] from afternoons to the early-morning shift.


Whether sleep deprivation played a heavy hand, or even a minor role, in the incident is still to be determined. But it serves as a reminder to everyone -- even non-transportation workers -- about the dangers of drowsy driving.


According to a CDC report published in January, 730 people died and about 30,000 were injured in drowsy driving-related car accidents[3] in 2009, though modeling studies show that as many as one third of fatal car accidents are linked to drowsy driving.


Drowsy driving is more common among adults who sleep six or fewer hours a day, who snore, and who fall asleep during the day unintentionally. (University of Pennsylvania researchers previously found that short sleepers -- even if they feel well- rested -- are more likely to drive drowsy[4] than those getting more sleep each night.)


The CDC study also showed that one in 24 people has reported actually falling asleep while driving, though health officials say that number could be even higher[5] , the Associated Press reported.


According to a 2005 National Sleep Foundation poll, some people are more likely to drive drowsy than others. Young adults, between ages 18 and 29, are more likely than other older adults to be involved in sleep-related crashes[6] , while men are more likely than women to fall asleep while driving.


The same poll also showed that a quarter of people say they've driven drowsy during their work commute "at least a few days a month," while 4 percent said they drive drowsy every day[7] .



Driving while drowsy has been likened to driving while drunk, with a 2012 Archives of Internal Medicine study calling the two "synergic." [8] Wired reported on research from Utrecht University, which found that driving for two hours during nighttime is like driving buzzed[9] , and driving for three hours during nighttime is like driving intoxicated.


Despite these risks, Americans are becoming increasingly complacent about the dangers of drowsy driving. Results of a AAA survey released this year showed that 46 percent of people view drowsy driving as a serious threat[10] on the road -- down from 71 percent four years ago.


New Jersey was the first state in the nation to pass a law making drowsy driving a criminal offense, with the so-called "Maggie's Law" in 2003. Under that law, people who drive while being sleep-deprived[11] for the last 24 hours (at least) are considered to be committing reckless driving, and could face fines of $100,000 and imprisonment for up to 10 years. Since then, a number of other states have also passed similar laws against drowsy driving (click here for a list[12] ).


Infographics by Sarah Klein.



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  • ...Increase Stroke Risk


    Even without the typical risk factors, like being overweight or having a family history, short sleep can up your risk for stroke, according to 2012 research. Adults who regularly slept fewer than six hours a night had <a href="http://www.huffingtonpost.com/2012/06/11/sleep-stroke-risk_n_1586837.html">four times the risk of stroke symptoms</a>, HuffPost reported.




  • ...Lead To Obesity


    Too little sleep can spur some less-than-ideal food choices, including <a href="http://www.huffingtonpost.com/2013/02/25/sleep-portion-sizes-deprivation-food-calories_n_2735497.html">serving yourself larger portions</a>, and a hankering for junk food, thanks to some complicated hormonal changes that occur when you don't get sufficient shuteye. It seems that six hours of sleep or less <a href="http://www.huffingtonpost.com/2012/10/26/sleep-deprivation-obesity-leptin-ghrelin-insulin_n_2007043.html">bumps up production of the hunger hormone ghrelin</a> and limits leptin, which helps you balance your food intake, according to a 2012 review of 18 studies of sleep and appetite.




  • ...Up Diabetes Risk


    A pair of small studies from 2012 examined the link between poor sleep and insulin resistance, a telltale risk factor for diabetes. One found that among healthy teenagers, the <a href="http://www.huffingtonpost.com/2012/10/03/sleep-insulin-resistance-teens_n_1929374.html">shortest sleepers had the highest insulin resistance</a>, meaning the body is <a href="http://diabetes.niddk.nih.gov/dm/pubs/insulinresistance/#resistance">not using insulin effectively</a>, according to the National Institute of Diabetes and Digestive and Kidney Diseases. The second study examined fat cells, in particular, and found that cutting back on sleep <a href="http://annals.org/article.aspx?articleid=1379773">increased insulin resistance in these cells</a>, even when <a href="http://news.health.com/2012/10/15/sleep-deprivation-insulin-resistance/">diet and calorie intake were restricted</a>, Health.com reported.




  • ...Fuel Memory Loss


    You probably know that on the days when you are most tired, you're forgetful and unfocused -- but sleep deprivation can lead to <a href="http://www.sciencedaily.com/releases/2013/01/130127134212.htm"><em>permanent</em> cognitive issues</a>. The less we sleep, the less we benefit from the memory-storing properties of sleep. But additionally, a lack of sleep can cause <a href="http://www.huffingtonpost.com/2013/01/28/sleep-deprivation-memory-loss_n_2566999.html">"brain deterioration,"</a> according to a 2013 study, which may at least in part explain memory loss in seniors.




  • ...Damage Bones


    At least in rats, long-term <a href="http://ebm.rsmjournals.com/content/237/9/1101.full">sleep deprivation seems to contribute to osteoporosis</a>, according to a 2012 study. Researchers found <a href="http://www.huffingtonpost.com/2012/09/26/sleep-deprivation-bones-marrow_n_1898610.html">changes to bone mineral density and bone marrow</a> in the rodents when they were deprived of shuteye over a period of 72 days. "If true in humans, and I expect that it may be, this work will have great impact on our understanding of <a href="http://www.eurekalert.org/pub_releases/2012-09/sfeb-los_1091812.php">the impact of sleep deprivation on osteoporosis</a> and inability to repair bone damage as we age," Steven R. Goodman, Ph.D., editor-in-chief of Experimental Biology and Medicine, said in a statement.




  • ...Increase Cancer Risk


    A small (but growing) body of research suggests that short and poor sleep can up risk for certain types of cancer. A 2010 study found that among 1,240 people screened for colorectal cancer, the 338 who were diagnosed were <a href="http://onlinelibrary.wiley.com/doi/10.1002/cncr.25507/abstract">more likely to average fewer than six hours of sleep</a> a night. Even after controlling for more traditional risk factors, polyps were more common in people who slept less, according to the study. Getting just six hours of sleep a night has also been linked to an <a href="http://www.huffingtonpost.com/2012/09/06/sleep-breast-cancer-aggressive-deprivation_n_1854658.html">increase of recurrence in breast cancer patients</a>. The study's author has pointed to more and better sleep as a possible pathway of reducing risk and recurrence.




  • ...Hurt Your Heart


    The stress and strain of too little sleep can cause the body to produce more of the chemicals and hormones that can lead to heart disease, according to 2011 research. The study found that people who slept for six hours or less each night and have problems staying asleep had a 48 percent <a href="http://www.sciencedaily.com/releases/2011/02/110208091426.htm">higher risk of developing or dying from heart disease</a>.




  • ...Kill You


    It's not just heart problems that can lead to sleep-deprivation-related death. In fact, <a href="http://healthland.time.com/2010/09/02/lack-of-sleep-can-cause-depression-weight-gain-and-even-death/">short sleepers seem to die younger</a> of any cause than people who sleep about 6.5 to 7.5 hours a night, TIME reported. A 2010 study examined the impact of short sleep on mortality and found that <a href="http://www.journalsleep.org/ViewAbstract.aspx?pid=27894">men who slept for less than six hours of sleep a night were four times more likely</a> to die over a 14-year period. The study's authors called this link "a risk that has been underestimated."




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