Effects of Sleep Deprivation on Fire Fighters and EMS ... - NAEMT

<strong>Effects</strong> <strong>of</strong> <strong>Sleep</strong> <strong>Deprivation</strong> on Fire Fighters and Other EMS Responders
physical activity and other factors known to influence diabetes onset (Suwazono et al., 2006).
Diabetes also is a major risk factor for development <strong>of</strong> heart disease.
Shift workers are at increased risk for obstructive sleep
apnea (OSA). OSA is a common sleep disorder found
in approximately five percent <strong>of</strong> the general
population, but more than 10 percent <strong>of</strong> shift workers.
OSA is associated with obesity, hypertension, diabetes and heart disease. Due to their disorder,
those with OSA obstruct their airways during certain sleep stages and as a result, they are awakened
from sleep, never achieving normal restorative sleep architecture. They suffer from chronic daytime
fatigue and lowered alertness; without treatment, those with OSA have a six-fold increase in traffic
crashes (Teran-Santos et al., 1999). Although the precise connection between sleep deprivation,
shift work and OSA is not understood, the connection is so well recognized and the adverse effects
on alertness potentially so injurious, that regulations are in place to screen all commercial motor
vehicle operators for the disorder (Hartenbaum et al., 2006).
1.5d Immune System, Infection and Malignancies
Obstructive sleep apnea (OSA) also is
discussed in Section 2 (page 32) and in
Section 5 (page 59).
Normal restorative sleep is needed for optimum functioning <strong>of</strong> the immune system, which supports
the common wisdom that sleep deprivation increases susceptibility to infections (Mohren, Jansen
& Kant, 2002). Research indicates that inadequate rest lowers levels <strong>of</strong> immunoglobulins needed
to fight infections (Hui, Hua, Diandong & Hong, 2006).
<strong>Sleep</strong> deprivation appears to increase circulating blood factors that promote and indicate
inflammation (Vgontzas et al., 2004), and higher levels <strong>of</strong> these inflammatory markers have been
associated with an increased risk <strong>of</strong> cardiovascular disease. The finding that sleep loss may activate
inflammatory processes is another potential link explaining the association <strong>of</strong> sleep deprivation
and cardiovascular morbidity observed in epidemiologic studies (Meier-Ewert et al., 2004).
Identifying a link between work hours and malignancies is complicated by the many other factors
relating to cancer risk, such as exposure to carcinogens. However, the U.S. nurses health study
carefully has followed more than 80,000 women for more than 15 years. Nurses are the largest
group <strong>of</strong> U.S. shift workers, and findings indicated that nurses working a rotating night shift <strong>of</strong> at
least three nights per month for 15 or more years had an increase risk <strong>of</strong> colorectal cancer
(Schernhammer et al., 2003). Also among women, the risk <strong>of</strong> breast cancer is increased among
night shift workers (Megdal et al., 2005; Davis & Mirick, 2006). The large ongoing longitudinal
studies <strong>of</strong> men have involved male physicians, who generally have not worked in shifts and whose
job structures were more varied. As a result, the incidence <strong>of</strong> cancer among men working long
hours has not been well studied.
One <strong>of</strong> the speculated mechanisms relating work hours to malignancies among women is disruption
<strong>of</strong> normal circadian hormone levels. Gonadal hormone patterns among men also have a circadian
rhythm, which could be impacted by long work hours and sleep deficits (Axelsson et al. 2005). In
a cross-sectional study, men’s testosterone levels appeared to be influenced by shift work, as those
employees with sleep and fatigue problems had lower levels than workers without those problems
(Knutsson, 2003).
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