Comparing the work and rest hours of

United States Navy Sailors with

existing maritime regulations

Nita Lewis Shattuck, Ph.D.

Panagiotis Matsangas, Ph.D.

2

The Military Climate: Doing More with Less

Life at sea!

Life at sea!

Life at sea!

Life at sea!

Life at sea!

Life at sea!

Life at sea!

Life at sea!

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

Actigram of a typical work/rest pattern at sea

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

nlshattu@nps.edu

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