Human Fatigue Risk Management: Improving Safety in the Chemical Processing Industry

By Susan L. Murray and Matthew S. Thimgan

Human Fatigue Risk Management: Improving Safety in the Chemical Processing Industry teaches users everything they need to know to mitigate the risk of fatigued workers in a plant or refinery. As human fatigue has been directly linked to several major disasters, the book explores the API RP 755 guidelines that were released to reduce these types of incidents. This book will help users follow API RP 755 and/or implement a fatigue risk management system in their organization.

Susan Murray, a recognized expert in the field of sleep deprivation and its relation to high hazard industries, has written this book to be useful for HSE managers, plant and project managers, occupational safety professionals, and engineers and managers in the chemical processing industry. As scheduling of shifts is an important factor in reducing fatigue and accident rates, users will learn the benefits of more frequent staff rotation and how to implement an ideal scheduling plan.

The book goes beyond API RP 755, offering more detailed understanding of why certain measures for managing fatigue are beneficial to a company, including examples of how theory can be put into practice. It is a simple, digestible book for managers who are interested in addressing human factor issues at their workplace in order to raise safety standards.

• Covers sleep, sleep disorders, and the consequences of fatigue as related to high-hazard industries
• Helps improve safety standards at the plant level
• Provides information on how to comply with API RP 755 and related OSHA 29CFR1910 articles
• Relates fatigue and human performance to accidents, helping readers make a case for implementing a human fatigue risk management policy, which, in turn, prevents loss of property and life

• Language: English
• Publisher: Academic Press
• Release date: Jun 23, 2016
• ISBN: 9780128026649

Susan L. Murray

Susan L. Murray, Ph.D., P.E., Professor - Engineering Management & Systems Engineering, Missouri University of Science and Technology http://web.mst.edu/~murray/resume.html

Book preview

Human Fatigue Risk Management

Improving Safety in the Chemical Processing Industry

Susan L. Murray PhD, PE

Missouri University of Science and Technology

Rolla, MO, United States

Matthew S. Thimgan PhD

Missouri University of Science and Technology

Rolla, MO, United States

Table of Contents

Cover

Title page

Copyright

About the Authors

Foreword

Acknowledgments

Chapter 1: The consequences of fatigue in the process industries

Abstract

1.1. BP Texas City

1.2. Human factors and the BP Texas City accident

1.3. A Wake-up call for the processing industry

Chapter 2: Basics of sleep biology

Abstract

2.1. What is sleep?

2.2. Identifying sleep

2.3. What is sleep good for?

2.4. Consequences of sleep deprivation

2.5. Benefits of sleep

Chapter 3: Circadian rhythms and sleep–circadian interactions

Abstract

3.1. Circadian rhythms

3.2. Interaction between sleepiness and circadian rhythms

Chapter 4: Sleep hygiene recommendations

Abstract

4.1. Make sleep a priority

4.2. Light

4.3. Consistent bedtime

4.4. Bedtime routine

4.5. Noise

4.6. Temperature

4.7. Stimulants

4.8. Sleeping environment

4.9. Pain

4.10. Diet

4.11. Naps

4.12. Body posture

4.13. Exercise

4.14. Age

Chapter 5: Sleep disorders

Abstract

5.1. Sleep apnea

5.2. Insomnia

5.3. Narcolepsy

5.4. Restless leg syndrome (RLS)/Willis–Ekbom disease (WED)

5.5. Shift work disorder

5.6. Sleep–wake phase disorders

5.7. Parasomnias

5.8. Fatal familial insomnia

5.9. Hypersomnias

Chapter 6: Fatigue and human performance

Abstract

6.1. Fatigue and human error

6.2. Fatigue and hand-eye coordination

6.3. Fatigue and mood

6.4. Fatigue and memory

6.5. Fatigue and reaction time

6.6. Fatigue and attention

6.7. Fatigue and cognitive tunneling

6.8. Fatigue and decision making

6.9. Fatigue and working with others

6.10. Fatigue and marital life

Chapter 7: Fatigue and accidents

Abstract

7.1. Bhopal—fatigue and poor abnormal situation response

7.2. American Airlines 1420—fatigue and decline in situation awareness

7.3. NASA space shuttle—fatigue and decision making

7.4. Exxon Valdez—fatigue and work schedules

7.5. Three Mile Island and cognitive tunneling

7.6. Metro-North train derailment fatigue caused by circadian rhythms and sleep apnea

7.7. Fatigue’s role in accidents

Chapter 8: Fatigue-related regulations and guidelines

Abstract

8.1. OSHA and fatigue risk

8.2. NIOSH sleep-related publications

8.3. UK and EU regulations

8.4. Transportation fatigue regulations

8.5. Healthcare fatigue regulations

8.6. Conclusions

Chapter 9: Fatigue counter measures

Abstract

9.1. Schedule

9.2. Food and drink

9.3. A sleep-friendly bedroom

9.4. Lighting

9.5. Getting to sleep or back to sleep

9.6. Conclusions

Chapter 10: Work shifts

Abstract

10.1. Shift work

10.2. Work-shift schedule design

10.3. Managing work-shift scheduling

10.4. Evaluating work shifts using the HSE fatigue index

10.5. An example of health and safety executive’s fatigue index

Chapter 11: Work environment

Abstract

11.1. Introduction

11.2. Lighting

11.3. Temperature

11.4. Noise

11.5. Vibration

11.6. Color

Chapter 12: Work task design

Abstract

12.1. Introduction to work design

12.2. Work stress

12.3. Administrative solutions for work design issues

12.4. Workplace exercise

12.5. Engineering solutions for work design issues

12.6. Error proofing

12.7. Human reliability analysis

Chapter 13: Employee training

Abstract

13.1. Introduction

13.2. Addressing FRMS training reluctance

13.3. Training topics

13.4. Ways to Engage Trainees

13.5. Training for supervisors

13.6. Freely available FRMS training materials

13.7. FRMS training assessment

Chapter 14: Naps

Abstract

14.1. Perceptions of napping

14.2. Is sleepiness a problem at work?

14.3. Benefits of naps

14.4. Strategic napping

14.5. Napping recommendations for the workplace and for shiftwork

14.6. Nap facilities

Chapter 15: Compounds that alter sleep and wakefulness

Abstract

15.1. Over-the-counter substances

15.2. Prescription medications meant to alter sleep and sleepiness

15.3. Common prescriptions that can alter sleep regulation

Chapter 16: Creating a fatigue risk management system (FRMS)

Abstract

16.1. Call for fatigue risk management systems (FRMS)

16.2. Purpose of an FRMS

16.3. Roles and responsibilities

16.4. FRMS implementation

16.5. Training

16.6. Hours of service limits

16.7. FRMS resources

16.8. Assessing an FRMS

16.9. FRMS quality assurance questions

Chapter 17: Accident investigation

Abstract

17.1. Investigating accidents, incidents, and near misses

17.2. Considering human factors in an investigation

17.3. Fatigue as a contributing factor in accidents

17.4. Sample NTSB fatigue-related accident investigation

17.5. BP Texas City CSB investigation

Index

Copyright

Academic Press is an imprint of Elsevier

125 London Wall, London EC2Y 5AS, United Kingdom

525 B Street, Suite 1800, San Diego, CA 92101-4495, United States

50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States

The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, United Kingdom

Copyright © 2016 Elsevier Inc. All rights reserved.

No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions.

This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).

Notices

Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary.

Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility.

To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein.

Library of Congress Cataloging-in-Publication Data

A catalog record for this book is available from the Library of Congress

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library

ISBN: 978-0-12-802412-6

For information on all Academic Press publications visit our website at https://www.elsevier.com/

Publisher: Joe Hayton

Acquisition Editor: Fiona Geraghty

Editorial Project Manager: Lindsay Lawrence

Production Project Manager: Caroline Johnson

Designer: Matthew Limbert

Typeset by Thomson Digital

About the Authors

Dr Susan Murray is the Interim Chair of the Psychological Science Department and a Professor of Engineering Management & Systems Engineering at the Missouri University of Science and Technology. She earned her doctorate in Industrial Engineering from Texas A&M University. Her research and teaching interests include human factors, safety, process improvement, usability, and improving higher education. Prior to her academic position, she worked in the aerospace industry including 2 years at NASA’s Kennedy Space Center. Her goal continues to be making improvements to benefit workers and students.

Dr Matthew Thimgan runs the Sleep Biology Laboratory at the Missouri University of Science and Technology. He earned his doctorate in Cell and Molecular Physiology from the University of North Carolina, Chapel Hill. He continued his training in sleep biology at Washington University in St. Louis. He currently studies sleep in both the human and the fruit fly. In humans, he and members of his lab are identifying biomarkers of sleepiness. In the fruit fly, they are pursuing the genes and biochemical pathways that regulate sleep and wakefulness. His scientific contributions have appeared in general biology journals, book chapters, as well as journals for the sleep field.

Foreword

At the outset, I must say that this publication by Dr Susan Murray and Matthew Thimgan on, "Human Fatigue Risk Management," is a very timely and much needed treatise. It is even more important given the need for process safety and sustainable development; a rational and constructive approach to human factors; and the significance of human factors in risk analysis, safety performance, and occurrence of catastrophic incidents.

Worker fatigue is a risk factor and should be managed to prevent catastrophic incidents and improve safety performance. However, this area is not well studied and management systems often do not take into account the increasing complexity of chemical processes, interdependent chemical infrastructure, and the need for considering diverse and competing issues. This publication by Murray and Thimgan delve deeply into all the issues that come into play for human fatigue and innovative approaches to managing the risk.

Murray and Thimgan have been successful in taking a refreshing and poignant look at human fatigue and risk management; they have applied a thoughtful approach in a holistic manner for the analysis and control of risks inherent to human fatigue. The book starts with a very succinct description of the consequences of lack of human fatigue risk management, and then goes into extensive detail about all the factors that are important in assessing fatigue, the impact of fatigue on human performance and incidents, and finally ends up with a very constructive management system for human fatigue. In addition, descriptions of regulatory requirements for fatigue risk management are provided in an easy-to-understand language. The book also provides a very comprehensive review of methods used over the years to understand and manage human fatigue. I sincerely believe that the book has opened up a new vista and perspective on methodological improvements, necessary in the ever-increasing complexity of safe manufacturing and distribution in a competitive world. This book is a must read for process safety and risk-management professionals, human factors specialists, managers, and leaders who want to understand the underlying issues related to human fatigue risk management and effective approaches to dealing with these issues.

M. Sam Mannan

Regents Professor and Executive Director, Mary Kay O’Connor Process Safety Center, Texas A&M University, College Station, TX, United States

Acknowledgments

The authors wish to acknowledge and thank the individuals at Elsevier whose technical expertise made this book possible. In particular, we are in debt to Lindsay Lawrence, Fiona Geraghty, and Caroline Johnson without whom this book would still be just an idea.

Without Dr. Sam Mannon’s encouragement and support to include human factors in the effort to improve process safety we would not have even started working in the area of human fatigue risk management. We also thank the reviewers that provided useful feedback on the book proposal.

Thanks to all of the researchers that have dedicated their talents to understanding the impact of adequate sleep on our health and performance as well as how to best incorporate these lessons to improve our lives. Also, a debt of gratitude is owed to the subjects that have allowed themselves to be studied to obtain this important information.

On the personal level we would like to thank our families for their support and understanding while we worked on this book. Without you: Julie, Jack & Dace and Katie, Andrew & Marcus this book would not have been possible.

From Matt:

I need to thank Susan Murray for her guidance and effort in pushing this book forward. She has used all of her experience and expertise to develop the final manuscript. She has been patient and encouraging with this naïve author.

From Susan:

On an individual level, I need to thank Matt Thimgan. Without you I would still be struggling with the biology of sleep. I look up to you not just because you are 15 in. taller than I am but for your expertise and passion as a sleep researcher.

Finally, I need to acknowledge my mother. She died during the writing of this book, which made me realize how much support, encouragement, and love she had given me my entire life. I miss you dearly.

Chapter 1

The consequences of fatigue in the process industries

Abstract

This chapter introduces the danger of sleep-deprived and fatigued workers in the industrial workplace. An example of horrific accidents including the Bhopal tragedy and the BP Texas City explosion is included. This chapter explores the motivation behind fatigue risk management systems, which are a data-driven approach to minimize the hazard of errors and poor decisions made by tired workers.

Keywords

BP Texas City explosion

fatigue risk management systems

sleep deprivation

1.1. BP Texas City

On Mar. 23, 2005 the BP Texas City Refinery suffered an industrial accident that killed 15 people, injured another 180, and resulted in financial losses exceeding $1.5 billion [1]. The incident occurred when the raffinate splitter tower in the isomerization (ISOM) unit was overfilled with a flammable liquid hydrocarbon. The chain of events leading to this deadly accident spanned several hours. Operational procedures were violated. Critical alarms and control instrumentation provided false indications that failed to alert the operators of the overfill situation. The refinery control room was understaffed and those who were there were exhausted and thoroughly sleep-deprived. When a pressure relief device released flammables there was a lethal series of explosions and fires.

Due to the significance of the disaster, the US Chemical Safety and Hazard Investigation Board (CSB) investigated the BP Texas City facility (the third-largest oil refinery in the United States), management at BP’s corporate level, the effectiveness of the Occupational Safety and Health Administration (OSHA), and the industry as a whole. The CSB concluded that the Texas City disaster was due to organizational, safety culture, and human factors at varying corporate levels. Repeated warning signs had been present for years, yet steps were not taken by BP to effectively prevent the tragedy that ultimately happened. The serious safety culture deficiencies were further documented when the refinery experienced two additional serious incidents just a few months after the 2005 explosion. A pipe failure caused a reported $30 million in damage in one accident and the other resulted in a $2 million property loss. In each incident, community shelter-in-place orders were issued [1]. The CSB’s 2007 Final Report included a strong focus on causes beyond faulty equipment and operator errors. It was an admonition for the processing industry to improve safety by understanding the human element and to consider workers’ limitations.

The CSB’s Final Report contained the one of the strongest analyses of human factors as an industrial accident cause. It explored the connections between human fatigue, human performance, and industrial safety in a very detailed fashion. The report established that the individuals working at the time of the accident were clearly severely sleep-deprived and that fatigue risk management was a safety issue that needed to be addressed in the chemical processing industry (Fig. 1.1).

Figure 1.1   Photo of BP Texas City after the accident.

(a) From the CSB website. (b) From the final report. (Sources: Part a: http://www.csb.gov/bp-texas-city-investigative-photos/. Part b: http://www.csb.gov/bp-america-refinery-explosion/.)

1.2. Human factors and the BP Texas City accident

During normal operations a total of four crews worked rotating 12-h shifts at the BP Texas City Plant. Prior to the accident, the ISOM unit was shut down and operators were split into two crews working 12-h shifts during the turnaround operations [1]. On the day of the accident, the day board operator was likely experiencing both acute sleep loss and cumulative sleep debt. He had worked 12-h shifts for 29 consecutive days and generally slept 5–6 h per 24-h period. The day lead operator—who was overloaded training two new operators, dealing with contractors, and working on the ISOM turnaround—had been on duty for 37 consecutive days without a day off prior to the accident. The crew members had a significant commute to and from the refinery. It was common for them to only get 5–6 h of sleep a night.

Fatigue can increase errors, delay reactions, and hamper decision-making [2]. The CSB concluded that fatigue caused by sleep deprivation among the operators working that day degraded the cognitive abilities and performance in solving the overfilling situation. The report [1] stated:

In the hours preceding the incident, the tower experienced multiple pressure spikes. In each instance, operators focused on reducing pressure: they tried to relieve pressure, but did not effectively question why the pressure spikes were occurring. They were fixated on the symptom of the problem, not the underlying cause and, therefore, did not diagnose the real problem (tower overfill).

Tower overfill was not discussed by the operators during their troubleshooting before the explosion. This type of focused attention to the exclusion of other critical information is called cognitive tunneling and is a common effect of fatigue.

Another key finding from the report was that BP has no fatigue prevention policy or regulations for operators. The contract between the United Steelworkers Union and BP provides a minimum number of hours per work week requirement, but not a maximum. According to BP, operators were expected to work the 12-h, 7-days-a-week turnaround schedule, although they were allowed time off if they had scheduled vacation, used personal/vacation time, or had extenuating circumstances that would be considered on a case-by-case basis. The company did have fatigue prevention policies that addressed motor vehicle transportation. The BP document states that when multiple fatigue factors are present, a strong argument can be made that fatigue contributes to accidents [3].

Fatigue Risk Management in Transportation

Hours of service rules have a long history in the transportation industry. Rules for truck drivers were originally established by the federal government around 1939. These rules remained in place, virtually unchanged for decades. The rules were based on consensus rather than science.

OSHA does not have regulations on fatigue prevention that applies to the chemical process industry or oil refinery workers. Other industries in the United States such as nuclear and transportation have government regulations concerning shift work. Many safety professionals joined the CSB in calling for companies in hazardous chemical processing to establish shift work policy to minimize the risks associated with sleep-deprived workers.

1.3. A Wake-up call for the processing industry

The exceptionally demanding work schedules for the ISOM crew at BP Texas City are not uncommon. Workers can be driven to work long shifts without time off for overtime incentives. Management has economic pressures to return to production as quickly as possible. The CSB and others called on management to establish shift work policies with the goal of minimizing the effects of fatigue and reduce the hazards associated with sleep-deprived workers monitoring and operating dangerous chemical processes.

In response to this call for an industry guideline for fatigue risk management, the American Petroleum Institute (API) and the American National Standards Institute (ANSI) created the Fatigue Prevention Guideline for the Refining and Petrochemical Industries. This recommended practice (RP) provides guidance to management and workers on understanding, recognizing, and managing fatigue in the workplace. The guideline, ANSI/API RP 755, calls for companies to develop a fatigue risk management system (FRMS). These systems should include education on the biology of sleep and the potential dangers of fatigue and sleep disorders. The goal of the sleep education is to make workers, their families, and supervisors aware of the health reasons for sufficient sleep as well as the safety concerns. The API guideline also addresses limiting hours and the number of days operators can work.

The FRMS should be developed for the specific organization and be tied to other operational and safety procedures. The FRMS should address the following topics:

▪ Positions in a facility covered by the FRMS;

▪ Roles and responsibilities of those covered by the FRMS;

▪ Staff workload balance assessments;

▪ Safety promotion, training, education, and communication;

▪ Work environment;

▪ Individual risk assessment and mitigation;

▪ Incident/near miss investigations;

▪ Hours of service guidelines;

▪ Call-outs;

▪ Exception process; and

▪ Periodic review of the FRMS to achieve continuous improvement.

API RP 755 is only a handful of pages long and is a recommended practice rather than an enforceable regulation. Yet it is a clear indicator that the process industry has recognized the importance of human fatigue as it relates to safety. It highlights the importance of fatigue countermeasures. Unlike early efforts to limit duty hours, the FRMS also addresses the other factors that influence human performance and fatigue-related safety [4].

Sleep researchers continue to demonstrate the negative effects of sleep deprivation on workers. Decision-making skills decrease, both in monotonous and emergency situations, when workers do not have sufficient sleep [5]. Group interaction and decision-making are also affected by fatigue [6]. Researchers have shown that individuals who have gone without sleep or have an accumulated sleep debt perform comparably or worse than those with an elevated blood alcohol level [7].

Cost of Sleep Loss to Industry

A recent study estimated the prevalence of insomnia was 23.2% and that it resulted in an average lost work performance equivalent to 11.3 days of work per individual. This was estimated for the total US workforce to be a $63.2 billion loss.

The costs associated with the consequences of sleepiness on the job can be astronomical (litigation, accidents, productivity, health care, etc.), and the impacts can be pervasive across families, communities, and organizations. It is important for managers and safety professionals to understand how sleep affects human physical and cognitive performance. This knowledge can be used to address possible risks and develop solutions. Although there is no simple, universal solution to fatigue in the workplace, a variety of countermeasure strategies have been proposed to maintain alertness and on-the-job performance. Something as simple as adjusting work schedules can have significant safety and performance benefits with a low cost. The design of an operator’s workstation and work task may help reduce fatigue and improve performance. While the BP Texas City accident was not solely caused by human fatigue, it was a clearly a very significant factor. It is important that we understand human limitations and heed the wake-up call of API RP 755 and improve industrial safety. The processing industry must sincerely implement FRMSs and not wait for another tragedy.

References

[1] CSB Texas City Final Report. Retrieved from http://www.csb.gov/assets/1/19/csbfinalreportbp.pdf

[2] Orzeł-Gryglewska J. Consequences of sleep deprivation. Int J Occup Med Environ Health. 2010;23(1):95–114.

[3] US Chemical Safety and Hazard Investigation Board, Investigation Report No. 2005-04-I-TX Refinery Explosion and Fire, March 2007.

[4] Lerman SE, Eskin E, Flower DJ, George EC, Gerson B, Hartenbaum N. American College of Occupational and Environmental Medicine Presidential Task Force on Fatigue Risk Management. Fatigue risk management in the workplace. J Occup Environ Med. 2012;54(2):231–258.

[5] Harrison Y, Horne JA. The impact of sleep deprivation on decision making: a review. J Exp Psychol Appl. 2000;6(3):236–249.

[6] Barnes CM, Hollenbeck JR. Sleep deprivation and decision-making teams: burning the midnight oil or playing with fire? Acad Manage Rev. 2009;34(1):56–66.

[7] Williamson AM, Feyer A. Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. J Occup Environ Med. 2000;57(10):649–655.

Chapter 2

Basics of sleep biology

Abstract

This chapter is an educational chapter on the basics of sleep science. There are numerous recommendations and requirements that come with an FRMS, and this chapter provides information on the biology and the science that underlies these recommendations. Although the FRMS can address many of the common problems of sleep, it cannot be expected to address every unique situation and possibility. Therefore, an FRMS educational program should communicate our best understanding of the biological principles of sleep, circadian, and work performance. This way, both management and employees can integrate these principles in their everyday lives and practices to improve outcomes, and the consequences of sleep deprivation. An understanding of these principles will help an employee plan their day and incorporate adequate sleep time in their schedule. This chapter will also present why sleep is important and understand the consequences of sleep deprivation. Benefits of adhering to the principles of this chapter include better performance on the job and potentially lower health-care costs as workers will be healthier and there will be potentially fewer workers’ compensation claims.

Keywords

sleep

sleep debt

cognitive performance

health outcomes

sleep deprivation

basics of sleep

sleep education

basics of sleep

cardiovascular

diabetes

glucose handling

quality of life

sleep cycles

slow-wave sleep

REM sleep

One of the cornerstones of any fatigue risk management system is an education program to communicate the principles of sleep and circadian biology. An understanding of basic sleep and circadian science will help employees and supervisors adapt these principles to the unique challenges that comprise each work environment. Not every scenario can be anticipated and have a predetermined response; therefore having knowledge of the underlying biology may help all parties come up with the best and safest solution. In this chapter, we will introduce the major biological principles that govern sleep and wake regulation and discuss the consequences of sleep deprivation. In Chapter 3, Circadian Rhythms and Sleep-Circadian Interactions, the concept and impact of circadian rhythms and their interaction with sleep debt will be addressed. Sleep and circadian rhythms interact to determine the timing and quality of sleep as well as the ability to vigilantly and accurately perform tasks.

Life is constantly changing. The implications of this obvious statement are substantial. Numerous technological advances have made life much more convenient, informative, and many would suggest more enjoyable. We have endless information and entertainment at our fingertips through both the internet and television. With streaming services, anyone’s favorite shows are available at any time and place for an endless duration. Other technologies in the past century have impacted sleep as well. The invention of the electric light bulb has revolutionized the way we schedule our lives, making it possible to be active throughout the night. Air travel has made every corner of the world accessible within a day for business or pleasure, altering circadian rhythms as one travels across time zones. Technological innovations such as televisions, smartphones, computers, and tablets have crept into and are now integral to our lives. Unfortunately, our biology has not adapted to the suddenness of these changes and they may negatively impact sleep in unanticipated ways. One such consequence is that it has been hypothesized that the electric light bulb is responsible for lost sleep [1], which may have contributed to a decrease in sleep times over the last century. This decrease in sleep is affecting our health and performance metrics.

Many variables determine whether a person is fatigued at any given moment when performing their work duties. Time on task, the difficulty or how engaging a task is, and the time of day, all affect our performance on a task at any given moment. Despite these other factors, one of the major determinants of fatigue is whether one has obtained the quality and quantity of sleep they require. How rested one feels at the outset of the day or at the beginning of the shift will provide the baseline from which the other factors will start to have their effects [2]. The more rested a person feels at the outset of their shift, the more one can counteract the fatiguing effects of the other inputs as one will start at a more alert and rested level. People are at their best, most accurate, and most energetic after a restful and consolidated night’s sleep. Conversely, people feel rundown, display a lack energy, and have a whole host of complaints when they do not get adequate sleep. As will be discussed in this chapter, inadequate sleep decreases a person’s quality of life, results in more emotional responses to situations, and numerous health and cognitive performance problems [3]. All of these consequences influence how a workplace functions and ultimately productivity. Therefore, it becomes important to understand what regulates the onset and maintenance of sleep, the consequences of sleep deprivation and what can be done if one cannot sleep so that both management and employee are aware of how important adequate sleep is and what measures can be taken to counteract sleepiness. Attending to one’s sleep can establish a low baseline for fatigue, which can prevent errors and make for a better work environment. The benefits of a well-rested workforce include fewer errors, more productivity, and a healthier workforce, which can increase the bottom line for a business.

2.1. What is sleep?

Sleep is a recognizable behavioral state. Though the person sleeping is inactive, current evidence supports the notion that sleep is not simply a resting state. Nearly as many calories are used during sleep as during waking [4]. During sleep, there is a stereotypical progression of the brain through sleep stages, suggesting a necessary pattern [5]. These concepts support the idea that there is an active process that helps restore the body during sleep. Under this hypothesis, daytime activities tax the system as memories are made, physical activity is carried out, and one negotiates daily activities. During the sleep period, a restorative process is carried out to prepare the body and mind for the next day’s activities [6]. Thus, a prominent hypothesis about the function of sleep results from a molecular restorative hypothesis.

Despite this prominent hypothesis, it is as yet unclear what exactly sleep restores or the mechanism by which restoration is carried out. On the basis of how people feel after consolidated sleep compared to how they felt before they slept, it is clear that something changes with sleep. In addition to restoration, there are other benefits to sleep. There is some energy savings that occurs during sleep and sleep helps to consolidate waking activity to the daytime for humans. People have evolved to find a safe, hidden, or protected place in which to sleep at night when is not optimal for them to be active [7]. Thus, sleep can occupy time that might otherwise be disadvantageous to be interacting with the world, such as night when our vision is impaired due to darkness. There is a large and increasing research effort to understand the function of sleep, help mitigate the consequences of sleep deprivation, and design better work schedules on the basis of optimal function of the human body.

Sleep is not a unitary process. When a person falls asleep, in many parts of the brain the activity decreases, yet in some parts of the brain the activity actually increases [8]. Different stages of sleep have different brain activity signatures, suggesting that they may have different functions. Also, the brain goes through a sequential set of events during sleep. This progression through the specific set of events has led to sleep researchers to label sleep as an active process [5]. One idea suggested by the progression of the brain through sleep is that the brain needs to go through this specific set of events in a specific order to accomplish the goals of sleep, and the order of these events may be critical to sleep’s function. Cognitive and physiological deficits are seen in people with fragmented sleep even though they obtain nearly equivalent sleep durations [9–12]. Moreover, the duration and quality of sleep is dependent upon the types of activity performed, in which increased brain activity will result in increased sleep intensity. This use dependent hypothesis suggests these cells then detect this usage and enhance the restorative effects of sleep locally to meet their increased need [13]. Moreover, current sleep drive is related to past sleep history [14,15]. If one is sleep deprived and then completes a full day’s activities, they will have more sleep drive than a person that does not start the day sleep deprived. These factors all work in concert to determine how sleepy one is at a given time. In Chapter 3, Circadian Rhythms and Sleep-Circadian Interactions, we will discuss circadian input to alertness, which has a major impact on performance at any given time of day.

2.2. Identifying sleep

Though we may not know exactly what happens during sleep, we do know how to recognize sleep in both humans and animals. Most people are familiar the polysomnography technique, often referred to as PSG. They may recognize the numerous wires attached to the head to record brain activity. This technique was used to define sleep stages and helped researchers to determine what happens in parts of the brain during sleep. But sleep did exist prior to the ability