SATURDAY, March 3 (HealthDay News) -- One in 10 American truck drivers, train conductors, airline pilots and other transportation workers may be dangerously sleep-deprived, a new survey suggests.

Many said they feel drowsy while working, and some worry that their fatigue poses a threat to commuter safety, the National Sleep Foundation (NSF) poll found.

As many as 11 percent of these employees work while sleepy, compared to 7 percent of non-transportation workers.

"It is exciting that we are finally able to see the statistics and hopefully do something to improve the situations for our transportation workers," sleep medicine expert Joyce Walsleben said.

Walsleben, who is an associate professor of medicine at the NYU School of Medicine in New York City, added that many transportation workers "are forced to work horrendous schedules, which puts us all in jeopardy. Too many societal tragedies have already occurred because of sleepiness."

The survey was conducted this year and is the first of its kind, the NSF said. It involved nearly 1,100 pilots, truck drivers, train engineers and conductors, and bus, taxi and limousine drivers (all over the age of 25), as well as non-transportation workers for a point of comparison.

Among the findings: roughly one in four train operators and airline pilots say their job performance suffers due to sleepiness at least once a week. By contrast, just one in six non-transportation workers say sleepiness has affected their work.

When it comes to "sleep dissatisfaction," pilots and train operators took the prize, with 50 percent and 57 percent, respectively, telling the survey team they rarely or never get decent sleep on nights they work. The same was true of 44 percent of truck drivers and 42 percent of non-transportation employees. By contrast, 29 percent of bus, taxi and limo drivers claimed a similar degree of sleep dissatisfaction.

Safety is at the heart of the problem, the poll suggested, with 20 percent of pilots admitting to having committed a "serious error" when flying. Just less than 20 percent of train operators said they experienced a "near miss" due to fatigue, with 14 percent of truck drivers acknowledging the same.

With transportation workers' shifts often subject to change, the survey showed sleepiness is not only an issue while on the job, but also a problem when these workers are commuting to work. Six percent of pilots and train operators said they have been in car accidents en route to work. This compares with just 1 percent of non-transportation workers polled.

"Transportation workers experience considerable variability in the days they work, the times they work and the amount of time off between shifts," Patrick Sherry, a sleep researcher and professor from the University of Denver Intermodal Transportation Institute, said in the NSF news release. "This makes it difficult for such workers to maintain regular sleep/wake schedules, which can, in turn, make it difficult for these workers to maintain alertness on the job."

Making work more regular might help. "Employers should put more effort into designing work/rest schedules that facilitate sleep and minimize workers' exposure to irregular, variable schedule changes," Sherry said.

Another sleep expert, Dr. Yosef Krespi of Lenox Hill Hospital in New York City, said the new survey should be seen as a "wake-up call" for employers.

He pointed to one 2003 study of 70,000 patients, and another from 2006 involving 14,000 people, that found that sleep deprivation is linked to increased risk of heart disease and hypertension. Krespi also noted that after 24 hours spent awake, the brain is no longer able to perform as well as when it is rested, with performance dropping to levels equivalent to that of a blood alcohol level of 0.1 percent, at or above the legal limit in most states.

"In other words," Krespi said, "extremely sleep-deprived individuals perform similar to drunks."

"Driving home from work after a long shift is associated with crashes due to sleepiness," Dr. Sanjay Patel, a sleep researcher at Brigham and Women's Hospital and Harvard Medical School in Boston, noted in the NSF news release. "We should all be concerned that pilots and train operators report car crashes due to sleepiness at a rate that is six times greater than that of other workers."

Noting that about one in 10 Americans say they are likely to fall asleep at unplanned and inappropriate times, such as in meetings or while driving, the NSF survey team advised anyone who suffers from regular sleepiness to seek professional help.

"Transportation professionals need to manage sleep to perform at their best," NSF CEO David Cloud said in the news release.

More information

For more on excessive sleepiness, visit the U.S. National Library of Medicine.