Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, May 14, 1995 TAG: 9505150100
SECTION: NATIONAL/INTERNATIONAL PAGE: A-11 EDITION: METRO
SOURCE: The New York Times
DATELINE: LENGTH: Medium
In a study involving 159 commercial truckers, 78 percent suffered from the disorder, obstructive sleep apnea, an incidence at least three times higher than that found in the general population, said Dr. William C. Dement, director of the Sleep Research Center at the university in Palo Alto, Calif.
``When 78 percent of the people coming toward you on the road in 40-ton trucks have such a disorder, you have a problem,'' Dement said.
The results of the study, which Dement conducted with Dr. Riccardo A. Stoohs and Dr. Christian Guilleminault of Stanford, are reported in the current issue of Chest, a journal of the American College of Chest Physicians.
Obstructive sleep apnea causes a person to momentarily stop breathing and then awaken briefly. The sleep interruptions, which can occur hundreds of times a night, are most often not consciously noticed, but they can drastically reduce the quality of rest and cause fatigue in waking hours.
``If someone wakes up every two or three minutes throughout the night, it's as if they had very little sleep or no sleep at all,'' Dement said. ``That can lead to grave mistakes.''
The condition usually arises when muscles in the upper airway become excessively relaxed during sleep, allowing excess tissue at the back of the throat to obstruct breathing. Enlarged tonsils or adenoids, a large tongue, a small airway opening or other structural abnormalities can also cause the condition. It is much more common in men, particularly overweight men, than in women, and is often associated with loud snoring, Dement said.
Left untreated, obstructive sleep apnea can have other serious consequences besides fatigue: the entire cardiovascular system can be strained by reduced oxygen flow to the brain and vital organs, Dement said.
The 145 men and 14 women who participated in the study wore small electronic screening devices to bed one night. The instrument monitored heart rate, blood oxygen levels, body position and recorded snoring. The data were analyzed by computer to determine whether a person suffered from sleep apnea. Because of the small number of women in the study, no gender-related conclusions could be made.
The researchers speculate that irregular sleep patterns, lack of exercise and a tendency to be overweight may all help explain the high incidence of the disorder in the drivers.
Julie Beal, a spokeswoman for the National Transportation Safety Board in Washington, said a recent review of fatal-accident statistics indicates that fatigue - the most frequently cited probable cause - is a factor 31 percent of the time. Fatigue is also a factor in 40 percent of all accidents involving heavy trucks, Beal said.
by CNB