sleep, circadian rhythms, and performance applying sleep science to operational practice gregory...

Sleep, Circadian Rhythms, and

PerformanceApplying Sleep Science to Operational Practice

Gregory Belenky, M.D.

Hans Van Dongen, Ph.D.

Sleep and Performance Research CenterWashington State University Spokane

Sleep and Performance Research Center Washington State University

The Earth at Night:

The Problem of 24/7 Operations

From www.freemaninstitute.com/nightearth.htm

Sleep and Performance Research Center

Fatigue Degrades Performance• Fatigue degrades performance:

– Simple performance, e.g., reaction time– Complex performance, e.g., accurate situational awareness– Perseverance slips into perseveration– Overall, slowing the Observe, Orient, Decide, Act (OODA) Loop

• Fatigue is a combination of – time awake (sleep loss)– time of day (circadian rhythm)– time on task (workload)

• Simple and complex performance are degraded by – extended time on task– sleep loss– adverse circadian phase

• Performance is impaired by systematic degradation and increased instability


Components of Fatigue:

Time Awake, Time of Day, Time on Task

Adapted from Wesensten et al., 2004


Physiology of Sleep

Washington State University


The 24-Hour Sleep/Wake Cycle

Two distinct states of sleep cycling with a 90-100 min periodicity

Recuperation is a function of total sleep time

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1200

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Non-Rapid EyeMovement Sleep

(NREM)

Rapid EyeMovement Sleep

(REM)

Waking


Total Sleep Deprivation Imaging StudiesT

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120

100

80

60

40

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Sleep Deprivation (Hours)0 24 48 72 86

- Mean Performance (N=17)- Cubic Spline- Linear Regression

PET Scans

From Thomas ML, Sing HC, Belenky G, et al. (2000). Neural basis of alertness and cognitive performance impairments during sleepiness. I. Effects of 24 h of sleep deprivation on waking human regional brain activity. Journal of Sleep Research 9: 335-352.And from Thomas ML, Sing HC, Belenky G, et al. (2003). Neural basis of alertness and cognitive performance impairments during sleepiness. II. Effects of 48 and 72 h of sleep deprivation on waking human regional brain activity. Thalamus & Related Systems 2: 199-229.


Brain Metabolism at 24, 48, & 72 Hours

of Sleep Deprivation

+ 32 mmAC-PC

24 h SD 48 h SD 72 h SD

+ 8 mmAC-PC

Z

1.65

2.33

2.58

3.08

> 4.16

N = 17

Relative to baseline, the prefrontal cortex and the thalamus are mostaffected by sleep loss

From Thomas ML, Sing HC, Belenky G, et al. (2000). Neural basis of alertness and cognitive performance impairments during sleepiness. I. Effects of 24 h of sleep deprivation on waking human regional brain activity. Journal of Sleep Research 9: 335-352.And from Thomas ML, Sing HC, Belenky G, et al. (2003). Neural basis of alertness and cognitive performance impairments during sleepiness. II. Effects of 48 and 72 h of sleep deprivation on waking human regional brain activity. Thalamus & Related Systems 2: 199-229.


Circadian Rhythm in Core Body

Temperature, Sleep Propensity, and

Performance



Circadian Rhythm in Body Temperature and

Performance

From Van Dongen HPA, Dinges DF (2005). Circadian rhythms in sleepiness, alertness, and performance. In Kryger MH, Roth T, Dement WC (Eds.), Principles and Practice of Sleep Medicine (4th ed.). Elsevier Saunders, Philadelphia, Pennsylvania: 435-443.

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Sleep Deprivation vs. Alcohol Intoxication

Dawson & Reid, 1997


Chronic Partial Sleep Restriction:

Effects on Performance

A Sleep Dose Response Study



From Belenky G, Wesensten NJ, Thorne DR, Thomas ML, Sing HC, Redmond DP, Russo MB, Balkin TJ (2003). Patterns of performance degradation and restoration during sleep restriction and subsequent recovery: a sleep dose-response study. Journal of Sleep Research 12: 1-12.

Psychomotor Vigilance Task Performance

across Sleep Restriction and Recovery


Recuperative Value of Sleep



Consolidated vs. Split vs. Fragmented Sleep• Recuperative value of sleep

depends on total sleep time over 24 hours

• Consolidated sleep– Nocturnal (night) – typically 7-8

hours; facilitated by circadian rhythm

– Diurnal (day) – typically ~ 5 hours; truncated by circadian rhythm

• Split sleep– 5 nocturnal / 2-3 diurnal

• Fragmented sleep– Awakening every 2-3 minutes– Fragmentation to this degree

abolishes recuperative value of sleep

• Sleep interrupted every 20 mins as recuperative as uninterrupted sleep


Bonnet M & Arand D (2003) Clinical effects of sleep fragmentation vs. sleep deprivation. Sleep Medicine Reviews, 7(4) 297-310


Objective Measurement of Sleep and

Performance in the Field Environment

&

Integration with Modeling



Objective Field Measurement of Sleep and

Performance

• Palm OS Psychomotor Vigilance Test (PVT)• 10 minute test

• Work/Sleep Log• Sleep periods• Start/Stop times of shift

• Actigraph watches• Wear 24hrs/day• Monitors sleep• More reliable than self-

reported sleep • Equivalent to

polysomnography in measuring total sleep time / 24 hours


Effect of Sleep Loss on Performance on the

Psychomotor Vigilance Test (PVT)


1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70

0

200 0

400 0

600 0

800 0

RESPONSE NUMBER

60 Hours Awake

36 Hours Awake

12 Hours Awake

84 Hours Awake

0

200 0

400 0

600 0

800 0

0

200 0

400 0

600 0

800 0

0

200 0

400 0

600 0

800 0

12 Hours Awake

36 Hours Awake

60 Hours Awake

84 Hours Awake


Actigraph Data Scored to Generate

Sleep/Wake History


Daytime Nap

Nighttime Awakening


Actigraph Sleep/Wake History Input to

Mathematical Performance Prediction Model


Nighttime Awakening Daytime Nap


Fatigue Risk Management System (FRMS)

• Five-tiered defense-in-depth to prevent fatigue-related errors, incidents, and accidents

• Tier 1 – Does system of shift timing and duration allow for adequate opportunity for sleep?

• Computer-based rostering

• Predictive modeling

• Tier 2 – Do employees take advantage of the sleep opportunity?

• Self-report

• Wrist-worn actigraph (sleep watch)

• Tier 3 – In the workplace, do they maintain adequate alertness and performance?

• Self-report & co-worker report

• Palm Pilot-based Psychomotor Vigilance Task (PVT)

• Embedded performance metrics

• Tier 4 – Are there errors, near misses?

• Tier 5 – Are there incidents and accidents?From Dawson D, McCulloch K (2005). Managing fatigue: It’s about sleep. Sleep Medicine Reviews 9: 365-380.


Reprise of Sleep Physiology and Performance

Fatigue is a function of sleep/wake history, circadian rhythm, and workloadSleep loss degrades performanceSleep restores it

All performance degrades with sleep lossSlower to observe, orient, decide, and act (OODA)

Adequate total sleep time sustains performanceNaps add to total sleep timeDivided sleep is as good as consolidated sleep

Performance and sleep propensity follow the 24-hour circadian rhythm in body temperature


The Sleep and Performance Research Center

Gang


Gregory Belenky, MDResearch Professor and DirectorSleep and Performance Research CenterWashington State University P.O. Box 1495Spokane, WA 99210-1495

Phone: (509) 358-7738FAX: (509) 358-7810Email: [email protected]

Point of Contact


The End



Consequences of Sleep Loss

Short term Minutes, hours

Error, accident, catastrophe

Mid-term Weeks, months, years

Bad planning, inadequate strategizing, poor life decisions

Long-term Years

Possibly promote cardiovascular disease, hypertension, overweight/obesity, type II diabetes, sleep disordered breathing

Triad of factors supporting health, productivity, and well-being Diet

Exercise

Sleep


Brain Metabolism during Non-REM and REM

Sleep

Frontal areas are deactivated during Slow Wave Sleep; decline in blood flow of ~30% (similar to sleep deprivation)

Frontal areas remain deactivated during REM; increase in flow to waking levels or above except in prefrontal cortex

Frontal areas are slowly reactivated after awakening (sleep inertia)

From Braun AR, Balkin TJ, Wesensten NJ, Carson RE, Varga M, Baldwin P, Selbie S, Belenky G, Herscovitch P (1997). Regional cerebral blood flow throughout the sleep-wake cycle. An H2

15O PET study. Brain 120: 1173-1197.


CDL Volunteers in the Laboratory

• Sleep measured with poly-somnography (electrodes, wires, recorders)

• Performance measured with computer-based tests.


Design of the Study

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

8 hrs in bed 3, 5, 7, 9 hrs in bed

AdaptationPhase Experimental Phase Recovery

Phase

4 5 6 7 8 9 10 11 12 13 14 15

Release from study

8 hrs in bed

1 2 3


Mean Sleep, Baseline, Experimental

Days, & RecoveryMean Sleep Experimental Days9 hr group – 7.9 hrs7 hr group – 6.3 hrs5 hr group – 4.7 hrs3 hr group – 2.9 hrs


Performance Prediction Modeling Integrated

into Rostering and Scheduling Software

Personal biomedical status monitoring Sleep/wake history (by sleep watch) Circadian rhythm phase (by technology TBD) Predict performance in real time person by person (by

biomathematical performance prediction model) Validate with embedded performance metrics, e.g.,

Lane deviation (trucking) Flight performance (commercial aviation)

Integrate performance prediction into rostering and scheduling software Integrate into the objective function Optimize along with other constraints Potential for automated/turnkey solution for fatigue risk management


sleep, circadian rhythms, and performance applying sleep science to operational practice gregory...

Documents

journal of sleep research

simple performance

sleep propensity

h of sleep deprivation

sleep lossfrom thomas

belenky g

neural basis of alertness

extended time