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Fatigue and critical care nurses

Considerations for safety, health, and practice

Hobbs, Barbara B. PhD, RN, NEA-BC; Wightman, Lori DNP, RN, NEA-BC

Author Information
doi: 10.1097/01.CCN.0000527220.26805.55
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Fatigue is a recognized concern for nurses, especially those caring for unstable and critically ill patients. Research shows that nurses working long hours and shift work, especially night shifts, are at risk for sleepiness and fatigue.1-4 Critical care nurses need to address factors contributing to fatigue and implement measures to reduce the effects of fatigue for themselves and their patients.5

Sleep loss and fatigue

Fatigue and sleepiness are not synonymous but can result from insufficient sleep duration and timing of sleep in relation to working hours.6 Sleepiness, drowsiness, and the desire to sleep are symptoms associated with both fatigue and a lack of sleep. Sleepiness is an increased propensity to fall asleep, resulting from an imbalance of the sleep-wake cycle; sleep is needed to restore balance. Fatigue is associated with sleep loss and the body's reaction to excess physical labor, limiting both physical and mental abilities.7

Physical fatigue occurs when the body's capacity for physical activity is limited or absent, whereas lack of motivation, exhaustion, lethargy, and feeling weary are outcomes of mental fatigue; both contribute to work-related illness and absence.4 Unlike sleepiness, rest periods can diminish temporary fatigue symptoms.

Both fatigue and sleepiness are attributed to an individual's lifestyle, the effect of working hours, sleep (quality and quantity), social time, exercise, and nutrition. There is consistent evidence that working when fatigued is unsafe and is linked to poor nursing and patient outcomes.5,8-10 Therefore, it is important for nurses to understand how work schedules and lifestyles affect the body's normal biological system, contributing to sleep disturbances and fatigue.

Nurses regularly care for critically ill and unstable patients who have sustained an extensive injury, had surgery, or been diagnosed with a life-threatening illness. The patient's health condition is tenuous and requires the nurse to assess, measure, and evaluate numerous data points, eliminating invalid data (for example, false alarms, anticipating potential changes in the patient's condition, acting on actual changes while coordinating care, and communicating with interprofessional healthcare team members).

Caring for critically ill patients is demanding because nurses need to be vigilant and responsive to minute-to-minute changes; these expectations add additional stress and are linked to mental and physical fatigue.11 However, the conditions most likely to contribute to nurses' sleepiness and fatigue are long working hours and shift work.8

Biologic rhythm and shift work concerns

Shift work is required to provide around-the-clock care to critically ill patients. Prevalent in service industries, shift and night work have been the focus of international research for over 50 years; shift workers' most common and consistent complaints include sleep loss, sleepiness, and fatigue.12,13 The need to improve patient outcomes and reduce healthcare errors has increased the awareness of working hours (shift work and long hours), sleepiness, and fatigue as factors affecting nurse and patient safety. Specifically, when the internal sleep-wake rhythm is disrupted, sleepiness and fatigue can impact the health and safety of nurses and patients.14

Human have evolved in the presence of external and environmental rhythms. The light-dark cycle (solar day) is the most prominent external rhythm. The body's internal rhythms, such as sleep-wake and activity-rest cycles, align with the solar day so individuals are awake and active during daylight hours and asleep during darkness.15 Shift and night work disrupt this sleep-wake cycle, requiring the nurse to work when it is dark and sleep during the day.

Chronotype is a person's preference for morning or evening activity, and is related to his or her underlying circadian rhythms.16 Chronotype is an individual factor that can affect shift work tolerance. Adaptation of the sleep/wake cycles to changing shift schedules takes longer than adjustment of social rhythms such as eating and exercise.17 The nurse who does not sleep well during the day and/or maintains a daytime routine to meet outside demands (for example, childcare, appointments, and so on) will struggle to adapt, which contributes to sleep loss, sleepiness, and fatigue.18

Scheduling and safety

The 24/7 nature of hospital care and critically ill patient complexity requires nurses to work varied shifts. Shift work assignment practices differ by institutions and units. They may be set and consistent or flexible, varying by week; permanent and rotating shift assignments are also common. Nurse administrators employ various scheduling strategies to ensure adequate patient-care staffing while supporting each nurse's requests. Self-scheduling is a strategy that permits more flexibility and allows nurses personal control. The ability to negotiate their final work schedules provides nurses autonomy in regard to their work-life balance.

Although shift lengths vary in time, 12-hour shifts (which nurses prefer) are common in CCUs.19,20 While there are reported benefits to working 12-hour shifts, there are significant risks associated with working 12 or more hours at one time. Evidence suggests that the risk of errors during the last 4 hours of a 12-hour shift is higher when compared with an 8-hour shift.10 In addition, the risk of errors increases when working more than 12 hours regardless of whether the time is scheduled, unscheduled, or volunteered.2

National guidelines suggest that working more than 40 hours per week should be limited because fatigue impacts performance and safety, contributing to an increased risk for errors after 40 hours. While preferring to work 12-hour shifts, critical care nurses should understand that their risk for having an accident or making an error reportedly doubles after 12 hours and triples when working 16 hours.8 Additional evidence on the effects of long hours and overtime on safety, health, performance, morbidity, and mortality is available.21

Fatigue-related accidents can increase when working four or more consecutive 12-hour shifts. Critical care nurses working 12-hour shifts have unintentionally fallen asleep during a shift when working five day shifts in a row.20,21 Research also shows a 17% greater accident risk on the fourth day shift worked compared with the first 12-hour day shift. More concerning, when working night shifts, there is a 36% higher accident risk on the fourth night worked compared with the first night worked.22 Recent studies revealed that critical care patients are at higher risk for medication-associated dosage errors when healthcare employees have worked longer shifts and hours.23

Critical care nurses need to recognize the risks associated with working too many shifts in a row without adequate rest breaks. As a guide, experts recommend scheduling no more than three 12-hour shifts in a row followed by two shifts off for rest and recovery.2 This is particularly important because critical care nurses reportedly receive less sleep when working consecutive 12-hour shifts, with as little as 5.68 hours between two night shifts.24

Critical care nurses also need to understand the risks of making critical decisions when they are tired or fatigued. Naps are an effective strategy and have been shown to reduce fatigue risks. A study supported by the American Association of Critical-Care Nurses examined self-reported fatigue and decision regret (near-miss medication errors) and found that higher reported fatigue was associated with greater decision regret.9

Naps are a simple strategy that critical care nurses can use to recover from fatigue and improve alertness. Establishing workplace interventions to improve worker health and provide night workers with an environment that promotes naps is supported by professional nursing and healthcare organizations.3,25

Self-scheduling provides nurses ownership of their work-life balance by allowing them to negotiate a schedule that fits their personal lives. The flexibility of self-scheduling is viewed as a nurse satisfier.26 However, scheduling experts suggest too much scheduling flexibility is disruptive and can lead to sleep loss and fatigue. Furthermore, factors such as short staffing, patient condition, and capacity demands can lead to nurses working overtime and/or extra shifts.

Scheduling practices vary, with some healthcare workers agreeing to work 7 days on followed by 7 days off. This practice is concerning because of the risk of accidents found after working three consecutive shifts.22 Guidelines recommend nurses limit work to 40 hours in a 7-day period—not per week. This recommendation takes into consideration that three shifts in 1 week should not be followed by three more shifts without at least 2 full days off.2

As nurses, it is important to start with an assessment. Examining individual lifestyle is imperative in order to determine how to transform it. Nurses need to ask themselves, “What is missing from my lifestyle?” The answer is most likely the integration of high performance, reenergizing, inspiring self-care that honors the best of the individual nurse paired with healthy nutrition and regular fitness.27

Nurses should continually evaluate their work hours, lifestyle practices, and stress levels, because all of these can contribute to physical and mental fatigue. Some specific lifestyle practices associated with fatigue include physical inactivity, recent transmeridian travel, poor sleeping habits, food and alcohol intake, and over-the-counter (OTC) and prescription medications.

Sleep and fatigue countermeasures

Sleep hygiene is a pattern of behaviors and routines implemented before bedtime in preparation for sleep. Nurses may benefit from the following recommended sleep hygiene practices to improve sleep quality and alertness.2,28,29

Sleep hygiene includes using both physical and mental strategies. Dr. G.P. McEnany, a sleep researcher and psychiatric mental health nurse practitioner, suggests that the best predictor of a good night's sleep is the anticipation of a good night's sleep.30 With this in mind, nurses need to mentally prepare for sleep and use relaxation strategies, such reading, doing light stretches, listening to calming music, and anticipating a good sleep, before bedtime. Avoiding stressful situations (for example, distressing conversations, action or suspense movies, and emotional interactions) is also recommended for good sleep hygiene.

Naps and rest breaks. Although difficult to obtain when working 12-hour shifts (especially night shifts), 7 to 9 hours of sleep in 24 hours is recommended. The total sleep time can be divided into two shorter sleep periods to achieve the total time. Establishing and maintaining a consistent sleep schedule (set times for sleep onset and waking) can improve sleep, but it is difficult to achieve when rotating shifts. However, integrating a consistent 4-hour sleep time that reoccurs daily can “anchor” the circadian sleep-wake cycle and reduce sleep disturbances.31

Naps and rest breaks are ways to reduce fatigue during working hours. Taking short, 20- to 30-minute naps during night shifts can be effective countermeasures.32 When working nights, naps are more effective at improving vigilance when taken between 1:00 a.m. and 3:00 a.m.33 Short naps (30 minutes to 2 hours) taken before a night shift are also effective at improving wakefulness and alertness.34 Conversely, naps contribute to sleep inertia and should be limited depending on the nap length and time of day. Professional organizations support strategically planned naps during nighttime work hours to reduce fatigue and promote alertness; however, nurses need to work collaboratively with their leaders to establish acceptable napping polices and protocols.2

Avoiding stimulants. Caffeine and naps can improve alertness, but the effectiveness of both can be altered depending on when they are utilized.9 Caffeine and nicotine are both stimulants that can disturb sleep.35 Caffeine intake should be discontinued 3 hours before scheduled bedtime. Likewise, nicotine and alcohol should be avoided at bedtime; participating in a smoking cessation program should be considered as part of a health and wellness program.35 While alcohol does have sedative type effects at the beginning of the sleep period, metabolizing alcohol disturbs the last half of the sleep period.36

Sleep setting. The bedroom should offer a quiet, calm atmosphere. The bed should be comfortable and include lightweight bedding. When possible, the bed should be decorated with soothing, dark colors. Window covers or eyeshades are recommended to block out light, and the room temperature should be neither too hot nor too cool.28,35

The bedroom should be free from all electronic devices, such as cell phones and personal computers; bright lights from these devices can impede sleep. When personal electronic devices are in use, place the item away from the bed so the light is not visible. Similarly, the light from a TV is sufficient to disturb sleep; therefore, nurses should keep the TV set out of the bedroom. Sleep guidelines do not recommend using electronic devices or watching TV in bed; however, if done, the electronics should have a sleep timer that is set to eliminate blue light.28

Noise while sleeping can be both beneficial and detrimental. White noise provided by a fan can aid sleeping, whereas environmental sounds (lawn mowers, telephones, and so on) disturb sleep. Soft, pliable earplugs can be worn to limit environmental noises that can affect sleep quantity and quality.29

Taking work breaks. Taking the time for meals and rest can reduce fatigue and aid critical decision-making. Taking breaks away from the intense working environment allows nurses time to meet physical needs (for example, snacks and rest while allowing time for mental debriefing). Working together with management, critical care nurses should establish a shift plan for nurses to eat and take breaks.

Meal schedules. Establishing a structured meal schedule (by shift) and allowing each nurse to select his or her preferred meal time for a given day help support a nurse's meal break and ensure adequate coverage for patient care. Nurses are more likely to take meal breaks when they know the staffing is adequate to cover patient care.37

Regular physical activity and exercise. Even 10 minutes of walking or other aerobic exercise can improve sleep. Although getting adequate exercise is difficult when working nights and/or 12-hour shifts, incorporating movement and activity (taking the stairs rather than the elevator) can be beneficial. When available, it is recommended that nurses participate in their employer wellness program. Although physical activity is important, strenuous exercise can disturb sleep and should be avoided 3 hours before bedtime.28

Choosing the right foods. Fatigue and sleepiness can affect food choices. Night workers reportedly consume more calories than day workers, which is a factor nurse shift workers should consider.18 Eating a larger meal during the night can reduce alertness and increase fatigue.38 Choosing the right foods can also help reduce fatigue. Carbohydrates, both complex and simple, raise energy levels, whereas eating protein aids endurance. Shift workers should consider eating a whole food diet, maintaining a 1-to-3 (protein-to-carbohydrate) ratio for meals.34

High glycemic foods that include simple sugars (for example, candy bars and cookies) should be avoided, as the energy boost generated from a rapid increase in blood glucose decreases as the blood glucose level drops back down. To improve sleep, nurses should avoid eating fried, spicy, heavy, and/or rich foods that may cause indigestion and disturb digestion. Large meals and highly carbonated drinks should also be avoided before bedtime. Fatigue is associated with dehydration, so drinking adequate amounts of water and other liquids is recommended.39

Reducing stress. Stress is associated with feelings of fatigue. Providing care to critically ill patients can add to nurses' stress; therefore, finding ways to reduce stress is important.7,34,40 Work-supported stress management programs may include exercise such as walking, yoga, and biking. Coping strategies such as meditation, reflection, and prayer can be beneficial for reducing stress. It is important to identify what coping strategies work for an individual, as strategies may work for some but not others.

Nurses tend to focus their development on enhancing technical skills. However, improving communication skills can reduce stress by improving the effectiveness of communications, relationships, and the ability to connect with others.

Adjusting light sources. Bright light, specifically sunlight, has the greatest influence on resetting an individual's circadian rhythm. When working nights, nurses can benefit from exposure to bright light. Improved alertness, daytime sleep (quality and efficiency), reduced sleepiness, and better physical fitness are effects of nighttime bright light exposure. Exposure to sunlight while driving home after working nights disrupts the sleep-wake cycle, stimulating activity and alertness, and delaying sleep onset. Wearing dark glasses (particularly blue light-blocking glasses) is a countermeasure nurses can use to reduce the sun's effect on resetting the body's internal clock and stimulate daylight activity.7

Pharmacologic measures. Melatonin, a naturally occurring hormone, increases with the onset of darkness and is necessary for sleep. Research findings suggest taking melatonin orally can increase daytime sleep duration; however, sleep latency (time to fall asleep) does not improve.41 Melatonin is available as an OTC tablet and can be taken approximately 30 minutes before bedtime to aid sleep.

OTC medications with histamine-blocking agents (diphenhydramine) should be limited due to residual drowsiness. Modafinil and armodafinil are oral medications that are approved by the FDA for adults to help improve wakefulness in those who have excessive sleepiness associated with shift work disorder, obstructive sleep apnea, or narcolepsy.42,43 Common adverse drug reactions include headache, nausea, dizziness, and insomnia. Nurses experiencing difficulty with either daytime sleeping or nighttime alertness should discuss options with their healthcare provider.


Nurses are at risk for work- and lifestyle-related fatigue so it is important to be aware of written standards, guidelines, and resources that offer suggestions for both nurses and employers. Nurses should assess their own fatigue level and initiate appropriate countermeasures. Collaborating with nursing leadership to address workplace fatigue and develop fatigue management systems is recommended.1-3,10 The American Nurses Association's (ANA) position statement addresses the “joint responsibilities of registered nurses and employers to reduce risks from nurse fatigue...create a culture of safety, a healthy work environment, and a work-life balance.”2

Professional nursing organizations are taking the lead to address nurse and workplace health. The ANA named 2017 “The Year of the Healthy Nurse,” offering written guidelines and suggestions each month, with July 2017 dedicated to healthy sleep (

Critical care nurses have a role in advocating for their own health and ensuring a healthy work environment that supports alertness and vigilance (see Fatiguestatements). These statements offer guidance recommendations for workplace changes to address nurse fatigue. Additional statements are available from certain state boards of nursing and professional nursing organizations.

Critical care nurses can also strengthen their own knowledge regarding the effects of sleep and fatigue on their health and safety. Several web-based training programs are available at the National Institute for Occupational Safety and Health (see Resources and training). In addition, the book Fit Nurse: Your Total Plan for Getting Fit and Living Well offers nurses guidance on self-care, fitness, nutrition, weight management, and stress management, and includes a chapter on coping with night shift work.27


Critical care nurses are at risk for fatigue and sleep-related issues that affect their safety, health, and practice. It is the nurse's responsibility to learn more about sleep and fatigue, consider the best evidence, and use countermeasures to reduce fatigue effects. Similarly, nurses need to collaborate with their facility's administration and advocate for environmental and scheduling changes to improve professional practice. In taking these measures, critical care nurses are meeting their practice obligations for their own health and wellness.

Fatigue statements

Emergency Nurses Association: Nurse Fatigue

National Association of Neonatal Nurses: The Effect of Staff Nurses' Shift Length and Fatigue on Patient Safety and Nurses' Health

National Association of Neonatal Nurses: The Impact of Advanced Practice Nurses' Shift Length and Fatigue on Patient Safety

Organization of Nurse Leaders: Position Statement for Patient Safety and Work Hours for Nurses position_3 final after board approval.pdf

Resources and training


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3. Blouin AS, Smith-Miller CA, Harden J, Li Y. Caregiver fatigue: implications for patient and staff safety, part 1. J Nurs Adm. 2016;46(6):329–335.
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critical care nursing; fatigue; patient safety; shift work; sleep; sleep-wake cycle; work-life balance

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