The sleep cure

| January 01, 2007

Staying alert on the road requires solid rest – not gimmicks or caffeine.

What’s keeping you up at 3 a.m.? According to sleep scientists, not much.

Drowsy driving is the primary culprit in a significant number of the more than 5,000 commercial truck crashes that happen on average each year, though estimates vary widely on just how many.

Tanker hauler Danny Fox averages a good eight hours sleep a night – or day. “Sometimes you may well be on days,” he says, “sometimes you’re on nights. Then sometimes you’ll be on afternoons.” Occasionally the Airgas Southwest driver will be looking at less time asleep, though, as straight daytime sleep he finds hardest to get through. Sleep scientists say this is natural. As Fox puts it, “You’re supposed to sleep at night.”

Fifty-year-old cattle-hauling owner-operator David Conannon, of Liberal, Kan., was known to push himself to the limit in the old days. He takes it a little easier, now, he says, but he’ll still pull a trailer full of bulls through a long night. He often drinks low-sugar energy drinks to keep himself alert. “They don’t have a lot of caffeine or sugar, though,” he says. “They don’t really work if you wait till you’re really tired to drink ‘em. You have to be steady with it, set yourself.”

In a pinch, he says, “power naps work even better. If it gets bad, I’ll get off at an exit, find a place I can stop and lay down for about 30 minutes.”

A nap’s a good choice because “sleeping is the most effective way to reduce sleepiness,” as a 1997 National Highway Transportation and Safety Administration report bluntly puts it. That report also identified over-the-road truckers, among other workers with irregular schedules, as one of three highest-risk groups.

How we understand drowsiness, or sleepiness, has changed in recent decades. People still use the words “fatigue” and “inattention” when talking about drowsiness behind the wheel, but as the NHTSA report makes clear, fatigue is more accurately defined as a specific desire to not continue the task at hand, whatever the task may be. And inattention is a by-product of drowsiness, not equivalent to it. Sleepiness, scientists have shown, is altogether different.

“Sleep is not something you can automatically do well,” says Dr. Allan I. Pack, director of the Division of Sleep Medicine at the University of Pennsylvania’s Center for Sleep and Respiratory Neurobiology.

What he means, partly, is that sleep is something our bodies drive us toward – the need for sleep is controlled by processes that go on below the level of our waking minds. The daily rhythms of the body are controlled by the circadian pacemaker, a group of cells within the suprachiasmatic nucleus in the hypothalamus region of the brain, and there are particular times during the day when it’s easier or harder to sleep.

Dr. Pack describes the pacemaker as a clock with two primary functions. “One is it controls the timing of sleep,” he says, “and it also gives out a time-varying alertness signal across the day.”

The times when it’s keeping you most alert vary from person to person, but it’s during these times that it’s a really bad idea to sleep. In a person on a “normal” sleep schedule the high alertness times might correspond to mid-morning, 8 to 10 or so, and “from 5 to about 8,” Pack says. “That’s considered by sleep scientists the absolute worst time to sleep because the clock is making you so alert at that time that you have real difficulty sleeping.

“Night shift workers who sleep during the day have poorer quality sleep and do not sleep as long as those of us who work by day and sleep at night.”

On the other hand, the clock sometimes makes it hard to stay awake. Averitt Express driver William Smith of Baton Rouge, La., echoes many when he says driving into the sunrise after a long night on the road is one of the most difficult times to stay awake. There is a natural dip in the signal the circadian pacemaker is sending when sun sets in the afternoon, but Dr. Pack says the main effect of light on the clock is to reset it, to let it know that the cycle is done. Perhaps the reported drowsiness at sunrise is the effect of the body’s confusion as to what time it really is.

“But as I get older I find I might want to take a nap in the afternoons,” says the 47-year-old Smith. “That’s the siesta.” Indeed, with the exception of nighttime, the time of day the body’s need to sleep is highest is early in the afternoon, between 1 and 3 p.m., if you’re on a standard sleep schedule. In the 1997 report, this daily period is generally defined as 12 hours from the midpoint of your previous night’s sleep. If, for instance, you went to bed at 11 and woke at 7, it’s likely you’d be most ready for a nap around 3 p.m., since the midpoint of your previous night’s sleep was 3 a.m.

The siesta came about naturally – in other words, from our biology – a shrine to the internal clock humans have possessed for ages. But in this go-go society, taking an afternoon siesta is rarely an option for drivers.

Dr. Pack and colleagues recently published a study, “Impaired Performance in Commercial Drivers: Role of Sleep Apnea and Short Sleep Duration,” in the August 2006 issue of the American Journal of Respiratory and Critical Care Medicine. The study sampled a total of 406 CDL holders (more than 80 percent were employed at the time of the study, though most were local haulers) and evaluated them for daytime sleepiness problems and the effect of the Obstructive Sleep Apnea disorder on daytime sleepiness, using three main methods:

  1. The Epworth Sleepiness Scale is a self-report sleep evaluation (take it yourself on p. 33) in which a final score of more than 10 is considered to represent a sleep abnormality. “In our sample,” Pack says, “32 percent of drivers had what we’d call ‘self-report excessive sleepiness.'” That 32 percent of drivers scored higher than 10 – a significant percentage, if they were being honest.

  2. The Multiple Sleep Latency Test yields a more objective measurement. Here researchers attempted to place a number on a driver’s potential to fall asleep at any given time. They put each driver in a dark room at four different, evenly spaced times during the day and told him or her to go to sleep, measuring the time it took the driver to fall asleep. An average time of less than five minutes was considered pathological or abnormal, and 25.7 percent of subjects fit this description.
  3. The Psychomotor Vigilance Task was developed by Dr. Pack’s colleague at the University of Pennsylvania, Dr. David Dinges. It’s an objective test meant to measure your reaction time and its vigilance over a specified period. Though there are different ways of conducting the test, Dr. Pack describes the study’s method this way: “What you’re doing is looking at a screen, and a light comes on and you need to respond by pressing a button. It’s coming on over a period of 10 minutes, and it’s coming on pretty frequently and erratically – you don’t know when it will come on next.”

A reaction time of more than 500 milliseconds is called a “lapse,” and the number of lapses and overall reaction time by the end of the test determine the result. Says Dr. Pack, “What you’ll find is that when people are sleepy they’ll do OK at the beginning of that task, but as time goes on, they’ll start to nod off and start missing the cues and have long reactions.”

The subjects here who showed significant performance problems were compared to subjects in another Psychomotor Vigilance Task study on subjects who were drunk. As the study says, sleepy drivers showed “performance decrements comparable to that induced in control subjects, albeit in different populations, after alcohol intoxication.”

Obstructive Sleep Apnea (OSA) is the most common of sleep disorders, behind chronic short sleep duration. A little snoring it is not. Rather, an “apnea” is a pause, and in this case the pause is in breathing during sleep when the muscles in the back of the throat aren’t able to hold the air passage fully open. These pauses wake you up momentarily, or bring you from a deep sleep to a more shallow level of sleep, ultimately resulting in insufficient sleep.

Many people have OSA – the National Sleep Foundation estimates more than 18 million Americans. Of the 406 drivers in Dr. Pack’s study, 118 had mild to moderate forms (with five to less than 30 pauses in breathing per hour), and 28 had severe OSA (more than 30 pauses per hour).

Only around 20 percent of the study group with mild or moderate OSA showed signs of chronic sleepiness. But Pack and colleagues also measured the amount of sleep each driver was getting on a regular basis. Among those who routinely received less than five hours of sleep a day and those with severe sleep apnea, the percentage was much higher.

OSA is readily treatable – in addition to eliminating risk factors such as smoking, alcohol consumption and obesity, a CPAP (Continuous Positive Airway Pressure) device is a mask you wear while sleeping that fits over the nose and is attached to a fan that delivers pressurized air to keep your airways open. There are likewise various helpful dental appliances that can adjust the position of your lower jaw or tongue. Surgery is an option for some, depending on the nature of their obstruction.

Over the course of 2003-2004, Schneider National ran its own trial screening and treatment program for drivers diagnosed with various forms of sleep disordered breathing, including sleep apnea. After initiating sustained treatment of a total of 348 drivers with CPAP devices, the company’s monthly health-care costs per member per month were down 47.8 percent in the control group, and among a subgroup of 225 drivers, preventable accidents were down by 73 percent, among other positive results. In short, if you’re suffering from sleep-disordered breathing of any kind, it’s in your company’s best interest to help you through it.

On that front, short sleep duration is both a much more serious problem in our society and “much harder to deal with,” says Dr. Pack. “The important and challenging thing to do is to create more understanding in the industry about the basic biology of sleep, the idea that sleep is not something that you can just do at will. You need to build programs that can allow people to get sufficient sleep. ”

Trucker William Smith sees the new hours-of-service regulations as helping, at least. “I try to use most of the available off time to sleep,” he says. “I’ve always been of the philosophy that nothing’s that important. There’s no freight that important, no company that important. Most of that’s a thing of the past. It is a relief that Averitt really insists on adhering to the guidelines and safety standards – it keeps us all safer and happier.”


Are You Getting Enough Sleep?
Epworth Sleepiness Scale can help you figure it out

The Epworth Sleepiness Scale was developed in 1991 by Dr. Murray Johns at Epworth Hospital in Melbourne, Australia. Dr. Johns was studying narcolepsy at the time, but this scale has been applied across the various research areas in sleep disorders as an effective, though subjective, measure of daytime sleepiness in subjects.

Measure your own typical daily dozing habits and drowsiness to see if they represent a possible disorder by matching the appropriate number to the situations described below. If you haven’t done some of these things recently, try to imagine the situation and compare it to things you have done. At the end, add all your numbers up.

Sitting and reading _____
Watching TV _____
Sitting inactive in a public place (for example, a theater or a meeting) _____
As a passenger in a car for
an hour without a break _____
Lying down to rest in the afternoon _____
Sitting and talking to someone _____
Sitting quietly after a lunch without alcohol _____
In a vehicle, while stopped for a few minutes in traffic _____

GRAND TOTAL _____

0 = no chance of dozing
1 = slight chance of dozing
2 = moderate chance of dozing
3 = high chance of dozing

A points total higher than 10 is generally considered to represent a possible abnormality and may indicate that you are not getting enough sleep or have a sleep disorder – but don’t take our word for it. See a doc.


A Good Night’s (Or Day’s) Sleep
It’s important to remember the basics before jumping to the conclusion that you have sleep apnea or another disorder, says Dennis Butler, a nurse practitioner in the University of Alabama Birmingham Hospital’s Division of Pulmonary Medicine, renowned for its treatment of sleep disorders. Butler recommends:

  1. Seven to eight hours of good, quality sleep per night in a quiet environment.

  2. A regular time to go to bed and wake up.
  3. Avoiding caffeine within four to six hours of bedtime.
  4. Avoiding alcohol within that time frame as well.

“If someone has issues with sleepiness in the face of good sleep habits,” Butler says, “they need to see their doctor. There are many things that will cause sleepiness besides sleep apnea.”

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