Force Science News #70
April 20, 2007
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In this issue
I. SNOOZE YOU LOSE? ACTUALLY, THE OPPOSITE MAY BE TRUE
II. FATIGUE LINKED TO FAULTY JUDGMENT, FEDERAL AGENCY SAYS
[NOTE: We'd like to hear your reaction to the observations and proposals
made by Trainer Tom Aveni in the report below. Please E-MAIL US at:email@example.com
. We'll print a representative sampling of responses in a
future edition of Force Science News.]
I. SNOOZE YOU LOSE? ACTUALLY, THE OPPOSITE MAY BE TRUE
Does your agency encourage you to nap on duty?
Probably not. But your department might get better performance and you might
be safer if regulated snoozing was permitted, according to well-known
trainer and consultant Tom Aveni, head of the Police Policy Studies Council
and a Technical Advisory Board member of the Force Science Research Center
at Minnesota State University-Mankato.
Recent research reports offer some impressive support for Aveni's
unconventional position by documenting the health and judgment benefits of
limited workplace dozing.
"Most of the egregious errors committed in law enforcement occur when
officers are fatigued or dealing with low-light conditions," Aveni pointed
out in a presentation on "Surviving the Night Shift" at a conference of the
International Law Enforcement Educators and Trainers Assn. (ILEETA). And the
rotating, irregular, or extended shifts common in policing contribute
significantly to officer fatigue, he declared.
"Those working rotating shifts, for example, average 5.5 hours of sleep when
working night hours," Aveni said. Because of second jobs, family
obligations, or disrupted sleep patterns, some officers, at least on
occasion, come to work with as little as 3 hours' sleep, "resulting in the
same level of impaired performance as ingesting the legal limit of alcohol.
"Sleep deficits may be partly recouped on days off," but until a full and
satisfying compensation occurs an officer's "mood and performance are
Given the slim, real-world probability of consistently getting sufficient
sleep, naps during duty hours could help officers fight dangerous fatigue,
Aveni argues, along with brief exercise breaks, proper caffeine intake, low
glycemic (sugary) food consumption, and exposure whenever possible to
brightly lighted areas.
"Napping is usually seen as being derelict of duty, but progressive agencies
really should encourage it. It's a healthy means of fighting fatigue, and a
short nap--20 to 30 minutes--can work wonders in increasing alertness and
Recent research studies tend to agree.
For instance, a 6-person research team at Stanford University, headed by Dr.
Rebecca Smith-Coggins, studied the effects of napping on 49 resident
physicians and nurses working nights (1930-0730) in a university trauma
center ER. Some were allowed to take up to a 40-min. nap at 0300, while a
control group stayed awake for the entire 12-hr. shift.
Napping was done in a dark, quiet room away from ER activities, with a bed
and linens provided. Ninety percent of the nap subjects, whose mean age was
30, were able to fall asleep quickly (within 11 minutes) and slept for an
average of nearly 25 minutes.
Before and after the shift and also after the nap period, both groups were
tested for vigilance, memory, mood, and task performance. After shift, all
subjects participated in a 40-min. driving simulation test to measure
"behavioral signs of sleepiness and driving accuracy."
At the end of shift, the nap subjects showed quicker reaction times and
fewer lapses in vigilance, according to the study. They reported "more
vigor, less fatigue, and less sleepiness" than those who had worked without
napping. Moreover, the nappers were able to more quickly complete a simple
job-performance task (the simulated insertion of a catheter IV) and
exhibited "less dangerous driving," although both groups showed signs of
driving impairment after working overnight.
The only negative outcome evident in the nappers was a temporary worsening
of memory "immediately after the nap." This was attributed to sleep inertia,
"the feeling of grogginess...that can persist for up to 30 minutes after
Generally, "nap intervention provided beneficial effects," the researchers
noted, and planned naps in the workplace might well "promote a high level of
alertness, attention to detail, and decision-making proficiency."
[A full report of this study appears in the Nov. 2006 issue of the Annals of
Emergency Medicine, under the title "Improving Alertness and Performance in
Emergency Dept. Physicians and Nurses: the Use of Planned Naps." A summary
appears at: http://www.aemj.org/cgi/content/abstract/9/5/466
Aveni speculates that some officers' moral judgment may also be improved by
fatigue relief in the form of napping. Certainly the findings of another
recent study suggest that morally framed decision-making can be negatively
impacted by extended fatigue, which tends to affect activity in the region
of the brain that plays a major role in moral reasoning.
In this study, Dr. William Killgore and colleagues at the Walter Reed Army
Institute of Research tested 26 healthy, active-duty military personnel
after 2 sleepless nights to see whether the lack of shut-eye would hinder
their ability to make decisions in the face of emotionally charged, moral
dilemmas. "The findings could have implications for people who are both
routinely sleep-deprived and often need to make quick decisions in a
crisis," the researchers said. That would include soldiers in combat and
cops on the street.
The participants were first tested after an adequate sleep period and again
after an unusually long stint (53.5 hours) of continuous wakefulness. They
were given a wide variety of decision-making scenarios, including some that
were highly emotionally charged, highly personal, and burdened with moral
For example, one scenario stated: "You are negotiating with a powerful and
determined terrorist who is about to set off a bomb in a crowded area."
Thousands of people would be killed by the detonation. Your one advantage is
that you have his teen-age son in your custody. [The] only one thing you can
do to stop him from detonating his bomb [is to] break one of his son's arms"
in front of a camera "and then threaten to break the other one if he does
not give himself up." The participants were asked: "Is it appropriate for
you to break the terrorist's son's arm?"
[All other scenarios used are described at:http://www.sciencemag.org/cgi/content/full/293/5537/2105/DC1
The researchers were not concerned with evaluating "right" or "wrong"
answers-only with analyzing the decision-making process. Among other things
they found that:
--the test participants took significantly longer to decide how to react to
the highly personal, morally charged situations when they were
sleep-deprived compared to when they were well rested. This suggests that
fatigue "has a particularly debilitating effect on judgment and
decision-making processes that depend heavily upon the integration of
emotion with cognition," the researchers concluded.
--sleep loss also led generally "to an increase in the permissiveness or
tolerance for judging difficult courses of action as appropriate," the study
found. Only participants with above-average "emotional intelligence," the
ability to empathize and interact socially with other people, showed
resistance to being influenced by sleeplessness in this regard.
Such findings "may have implications for those in occupations" frequently
associated with sleep loss "and in which real-world moral dilemmas may be
encountered.... When sleep deprived, such personnel may experience greater
difficulty reaching morally based decisions under emotionally evocative
circumstances and may be prone to choosing courses of action that differ
from those that they would have chosen in a fully rested state," the study
"The implications for police work, where life-and-death decisions must often
be made in crisis mode, is obvious," Aveni recently told Force Science News.
[A full report of this study can be found in the journal Sleep, vol. 30, #3,
2007, under the title: "The Effects of 53 Hours of Sleep Deprivation on
Moral Judgment." For an abstract, go to: http://www.journalsleep.org/ViewAbstract.aspx?citationid=3172
A third recent study concerned an important health benefit of napping.
A team of Greek and American researchers, headed by Dr. Androniki Naska of
the University of Athens Medical School, confirmed that people who take at
least 3 naps a week lasting 30 minutes or longer cut their risk of dying
from a heart attack by 37 percent.
The study followed more than 23,600 originally healthy men and women for
more than 6 years. Even those who napped only occasionally had a 12 per cent
lower coronary mortality rate than those who never napped. Men who were
working seemed especially to benefit.
Napping, the researchers said, appeared to reduce stress, and "there is
considerable evidence that both acute and chronic stress are related to
[A full report of this study appeared in Archives of Internal Medicine on
Feb. 12, 2007, under the title "Siesta in Healthy Adults and Coronary
Mortality in the General Population." A summary can be found at: http://archinte.ama-assn.org/cgi/content/abstract/167/3/296
"Police agencies need to start looking at napping as a restorative,
preventive measure, as something that can prevent serious errors," Aveni
"Other measures for fighting fatigue tend to be transitory. Rolling your
squad car window for a blast of cold, fresh air may perk you up for 2 to 3
minutes. Taking an exercise break where you do jumping jacks may buy you a
half hour's benefit. But with a nap of at least 20 minutes, you'll see a
pronounced improvement in performance, in vigilance, in eye-hand
coordination that can last up to 4 hours.
"Officers forced to work rotating shifts are thrust into an unnatural work
environment. In many cases, your body never adjusts to the changes in
schedule. Agencies need to consider effective countermeasures for safety's
Most agencies would understandably want to control where any officially
sanctioned napping takes place, Aveni acknowledges. Inside a patrol car is
not recommended, not only because of public perception but also because of
discomfort, distractions, and safety.
A sound-insulated area with recliners or cots inside a police facility is
more desirable, with naps scheduled in advance or permitted on request. Time
should be allowed, he says, to counteract sleep inertia upon awakening with
mild exercise before heading back on patrol.
Napping could become a collective bargaining issue in the future, Aveni
believes. But today, he admits, he knows of no department with an official
The precedent is there, however, in industries like trucking, railroading,
and aviation. A New York company called MetroNaps has started marketing
customized napping "pods"--7-ft.-long, hooded recliners with headphones,
temperature controls, and lights that dim--to corporations willing to be on
the cutting edge of a new trend.
Reflecting on other hazardous occupations where "preventive napping" has
become part of the culture, Aveni notes: "If we held law enforcement to
civilian standards, this would be a very different profession."
[REMEMBER: We welcome your reactions to Aveni's remarks at: firstname.lastname@example.org
II. FATIGUE LINKED TO FAULTY JUDGMENT, FEDERAL AGENCY SAYS
An association between fatigue and faulty judgment in life-or-death
situations is dramatically drawn in a recent review by the National
Transportation Safety Board of airline accidents and near misses.
"Even though the Board's report concerns air traffic controllers, law
enforcement officers, too, risk disastrous consequences from the effect of
sleep deprivation on brain function," Dr. Bill Lewinski, executive director
of the Force Science Research Center told Force Science News. "As with the
controllers, slower reaction times, missed cues, and foggy judgment brought
on by fatigue in cops can result in lost lives. The difference is that with
police officers the lives lost may include their own."
Lewinski cites a study some years ago of officer fatalities in auto
accidents. Researchers found that the highest-risk time for officers was
when driving home after a critical incident that significantly extended
their work day. "The combination of coming off an adrenalin dump and
entering a sleep-deprivation state produced fatigue that impaired their
attention and judgment with deadly consequences," Lewinski explains.
He also points out that most major disasters in the last 3 decades, from the
nuclear meltdown at Three-Mile Island to the explosion of the Challenger
shuttle, "were caused by individuals operating with significant sleep
deprivation, often on the first night of a new shift."
In a letter this month urging reform in scheduling and training, the NTSB
linked sleep deprivation in air traffic controllers to the worst U.S.
airline crash in 5 years and to at least 4 near-fatal incidents.
The fatal crash claimed 49 lives last August when a commuter jet tried to
use a closed runway in Lexington, KY. The controller on duty had reported to
work for the midnight shift after sleeping for only 2 hours.
The close calls included a controller working after only 4 hours' sleep who
ordered a passenger jet to take off directly into the path of another plane
in Chicago and a controller who cleared a cargo jet for takeoff on a closed
runway in Denver who had gotten 60 to 90 minutes of sleep before working an
"The human brain is most alert and functions best when well-rested,"
Lewinski says. "You may think you can will yourself to overcome fatigue or
compensate for it with caffeine intake, for example. But that's true only
within fairly rigid limitations. Beyond those limits, physiology will win
out, to your decided disadvantage."
[For more details, see "Fatigue threatens air safety, NTSB says," by Alan
Levin in USA TODAY, 4/11/07 at: http://www.usatoday.com/news/washington/2007-04-10-fatigue-air-safety_N.htm
(c) 2007: Force Science Research Center, www.forcescience.org