Dissertation/Thesis Abstract

Effects of a 72-Hour Work Shift on Stress Biomarkers in Sleep-Deprived Firefighters
by Sundberg, Neil, M.S., California State University, Long Beach, 2019, 94; 27546166
Abstract (Summary)

According to the Firefighter Behavioral Health Alliance (FBHA) there were 103 confirmed firefighter suicides in 2017, 139 in 2016, and 143 in 2015. In all instances the confirmed number of suicides exceeded the number of duty-related deaths for the corresponding year. This trend is evident in law enforcement officers as well as the Soldiers, Sailors, Airmen, and Marines that make up U.S. military servicemen and women. That means firefighters and other uniform-wearing civil servants are more likely to die by suicide than in the line of duty. The United States Department of Health and Human Services National Heart, Lung, and Blood Institute (NIH) links increased incidence of suicide to ongoing sleep deprivation. The high prevalence for occupational stress in emergency responders due to sleep deprivation and repeated and often continuous exposure to traumatic work events is a potential contributing factor to these alarming statistics. The purpose of this study, however, was to elucidate the physiological factors and biomarkers associated with stress in sleep-deprived firefighters on a much smaller short-term scale, during a 72-hour work shift.

Full-time, permanent Riverside County Fire Department (RCFD) personnel (n = 5) with 6.9 ± 7.75 (mean ± S.D., range 17.5) years of fire service, assigned as members of the second busiest fire engine/engine company in RCFD (E71) and the single busiest ambulance in RCFD (M71), participated in this observational, case study design. A preliminary health and fitness assessment (PHFA) was conducted at Fire Station 71 (STA 71) prior to start of the participants’ 72-hour work shift. Participants’ anthropometrics and blood capillary samples were taken during PHFA. HbA1c, and fasting lipid profiles to include triglycerides (TG), LDL, HDL, and total cholesterol were determined from blood capillary samples. Cor, T, BG, BP, PS and TG data were collected at 0800 and 2000 on days 1, 2, and 3 and at 0800 of day 4 during the 72-hour work shift. These time points were preferentially selected based on the intrinsic hypothalamic-pituitary adrenal (HPA) axis circadian rhythm and diurnal relationship associated with cortisol, specifically in regard to the cortisol awakening response (CAR).

Friedman ANOVA with Wilcoxon-Signed Rank pairwise comparison demonstrated significant differences in a.m. and p.m. cortisol levels, as expected with inherent diurnal variation, but notable increases in CAR between Day 2 and Day 3 a.m. (p = .01). Significant differences in both TG (p = .002) and BG (p = .016) a.m. to a.m., p.m. to p.m., and a.m. to p.m. levels were found. No significant differences in salivary T were found (p = .104).

These results suggest a significant increase in Cor on the third and final day of the 72-hour shift, and between stress biomarkers during that timeframe. The single largest department in California employs approximately 9,000 firefighters. Each one of those 9,000 emergency responders currently work 72-hour shifts. To the best of this researcher’s knowledge, this was the first study to investigate the stress biomarkers associated with 3 consecutive days of emergency calls, therein lies its significance. Additional research is needed to further elucidate the relationship between significant short-term acute increases in stress during the 72-hour work shift and the long-term ramifications of chronic exposure to stress biomarkers on the health and wellness of our civil servants.

Indexing (document details)
Advisor: Cotter, Joshua A.
Commitee: Schick, Evan E., Escobar, Kurt A.
School: California State University, Long Beach
Department: Kinesiology
School Location: United States -- California
Source: MAI 81/8(E), Masters Abstracts International
Source Type: DISSERTATION
Subjects: Occupational safety, Physiology
Keywords: Cortisol, Fire fighters, Firefighters, Shift work, Sleep, Stress
Publication Number: 27546166
ISBN: 9781658420532
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