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Comparing the work and rest hours of
United States Navy Sailors with
existing maritime regulations
Nita Lewis Shattuck, Ph.D.
Panagiotis Matsangas, Ph.D.
Navy Personnel
Officers17%
Enlisted83%
Male84%
Female16%
0%
10%
20%
30%
40%
50%
60%
25 oryounger
26 to 30 31 to 35 36 to 40 40 orolder
Officers
Enlisted
• The US military indoctrinates healthy US adults into a culture of sleep deprivation that persists throughout their careers.
• Like other shiftworkers, members of the military frequently exhibit “circadian scarring” and often engage in “binge sleeping.”
• Based upon scientific findings from research on both civilian and military populations, these sleep practices are associated with decreased performance and long term health consequences.
A Population of Shiftworkers and Poor Sleepers
Sleep debt begins on Day One of Military Service…
Note: Brown University data were collected on the Class of 1992 (Fall 1988 – Spring 1990
using self-report. USMA data were collected using actigraphy on the Class of 2007 Fall 2003
– Spring 2005 (Miller, Shattuck, & Matsangas, 2010).
6:45 6:52 7:04 6:59
4:50 5:06 5:17 5:12
0:00
1:12
2:24
3:36
4:48
6:00
7:12
8:24
1st Sem 2nd Sem 3rd Sem 4th Sem
Brown
USMA
A Comparison of Sleep between Brown University Students
and Cadets at USMA, West Point
…and continues throughout their careers
42%
8%
27%
21%21%
31%
9%
33%
2%
9%
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
Mysliwiec et al. (2012)725 Army, Navy, Air Force
Krueger & Friedman (2009)10,441 civilians
< 5
6
7
8
> 9
Even non-deployed military sleep fewer hours than civilians
Average Hours of Sleep per Day
NPS Sleep Studies 2002-2017
n=33
n=167
n=21
n=19
n=42
n=28
n=41
n=20
n=24
n=29
n=21
n=25
n=19
n=19
n=102
n=34
n=120
n=127
n=129
0 2 4 6 8 10
Op. Enduring Freedom…
Various operations
GOMEX 05-1
Sea trials
RIMPAC
RIMPAC
Sea trials
Predeployment Workups…
Predeployment Workups…
Rough Water Trials - SS<4
Rough Water Trials - SS≥4
Calm Water Trials - 2013/05
Rough Water Trials - SS≤4
Rough Water Trials - SS 5-6
Independent steaming…
Underway Training
Underway Training - RX Dep
Underway Training - RX Dep
During deployment20
0220
0120
0520
0420
0820
0820
0420
0720
0920
11/0
1-02
2013
2014
/01-
0220
1220
13Ju
ne20
14N
ov.
2014
2016
CV
N 74
SS
N/
SS
B NH
SV
2S
WIF
TC
G 70C
G 73
SS
B N73
0D
DG 93
FF
G 46LC
S 1
LCS
2D
DG
109
DD
G 65C
VN
68
DD
G10
6
Daily Sleep [hrs]
Sleep - Naval Operations
Last update: Mar 2017
Note 1: Blue bars indicate actigraphic sleep, gold bars are self-reported sleep
Note 2: Number centered on each bar refers to study sample size
Note 3: Horizontal lines indicate one standard deviation
Watch schedules
Circadian (24 hour)
2-section
6/6
12/12
3-section
4/8
8/16
4-section
3/9
6/18
Non-Circadian
3-section
5/10
6/12
4-section
5/15
Workday includes duties other than watchstanding.
Other watchbills may be implemented by the command
Shiftwork in U.S. Navy
Problem Statement and Study Goals
Problem Statement
• Crewmembers in the United States Navy (USN)– Work long hours with
limited opportunities to sleep
– Are habitual shiftworkers• Shifts result in circadian
misalignment equating to an 15 or 20-hour day
– Have no weekends or time for recovery
Study goals
• Compare the work and rest patterns of USN crewmembers with existing maritime regulations
• Investigate the association between the watchstanding schedule and the level of compliance with existing maritime fatigue regulations
18
Method
• Retrospective analysis of pre-collected data (N=184)– USS NIMITZ (CVN-68)
Reactor Department (RX)
• June 2014: 69 crewmembers using the 5hr-on/10hr-off schedule
• November 2014: 115 RX crewmembers using the 3hr-on/9hr-off schedule
– Sleep was assessed with wrist-worn actigraphy and daily activity logs 19
Method
• Activity log information aggregated in
– Work and Rest by day (midnight to midnight)
• Work time
– Watch periods, ship duties, maintenance,
training, and service diversion
• Rest
– Personal time, sleep, and meals
20
Maritime working standards
Standards
For seafarers
Maritime LabourConvention
(MLC)
Work ≤14 hours/24-hour
period
Work ≤72 hours/7-day
period
Rest ≥77 hours/7-day
period
United States Code (USC)
Work ≤36 hours/3-day
period
US Navy regulations
Navy Availability Factor (NAF)
Work ≤81 hours/7-day
period
Navy Standard Work Week
(NSWW) – obs.
Sleep ≥56 hours/7-day
period
USN does not have a
regulation dedicated to
work/rest times (except
aviation)
Results
• Participants– Predominantly young (25.0±3.72 years of age)
– Male (80%)
– Enlisted (95%)
• Crewmembers worked ≥14 hours/day for 21% of their workdays
• On a weekly basis, crewmembers– Worked ≥72 hours for 75% of their 7-day periods
– Worked ≥81 hours for 53% of their 7-day periods
– Rested <77 hours for 23% of their 7-day periods
– Slept<56 hours (~8-hours/day) for 64% of the 7-day periods
• From actigraphy: Crewmembers working on the 5/10 schedule slept on average 6.88±0.93 hours/day, compared to 6.68±0.95 hours of sleep for their 3/9 peers. 22
24
Non-compliance rates by work hours criterion
Vertical lines denote the Standard Error of the Mean
USS Nimitz Results for Work Hours
25
Non-compliance rates by rest/sleep hours criterion
Non-compliance rate refers to % of crewmembers
Vertical lines denote the Standard Error of the Mean
USS Nimitz Results for Sleep/Rest
Conclusions
• This study compared the compliance of crewmembers’ work/rest
hours with existing regulations. Overall, non-compliance rates were
high, up to 88% of the crew!
• Results highlight how crewmembers work long hours with limited
opportunities to rest.
• The watchstanding schedules of the crewmembers had a significant
impact on the compliance rates.
• In the absence of specific Navy regulations to manage work and rest
schedules, the US Navy should consider using standard maritime
regulations that include guidance for optimal management of
work/rest/sleep patterns.
26
Contact information:
Nita Lewis Shattuck, Ph.D.
(831) 656-2281
NPS Crew Endurance Resource Website
http://my.nps.edu/web/crewendurance
Questions?
Factors Leading to Disrupted Sleep at Sea
28
Factors Leading to Disrupted Sleep at Sea
Psychological-Pharmacological
Stress, anxious thoughts
Harassment from leadership,
crewmembers
Caffeine, energy drinks
Nicotine
Environmental
Ship motion
External noise
Smells
Temperature extremes
Berthing Compartment
Habitability
Lack of privacy
Internal noise
Temperature
Light in the compartment
Organizational
Irregular sleep schedules
Watch schedules
Long work hours
Duties/operational
commitments