Every person has experienced some form of stress in his or her life, but understanding exactly what stress is and how it affects an individual’s performance can be difficult. A situation that is stressful for one person may not be stressful for another. Sometimes stress can enhance performance, but many times it negatively affects how a flight crew member performs a task. The objective of this Briefing Note (BN) is to give an overview of what stress is and to provide best practices to help flight crews:
- Avoid negative stress whenever possible by being prepared to address stressors
- Recognize the symptoms of excessive stress
- Cope with stress effectively when it cannot be avoided.
Stress is a reaction that is initiated when a situation or event is evaluated as a threat and requires actions beyond an individual’s normal operational intensity level. From a physiological perspective, stress is a bodily response to a stimulus that disturbs or interferes with the “normal” physiological equilibrium of a person. An argument can be made that anything that requires a response is stressful because it disrupts an individual’s resting state. For the purposes of this BN, however, stress will refer to a state of physical, mental or emotional strain due to some external or internal stimulus.
Understanding the factors that lead to stress, as well as how to cope with stressful situations, can greatly improve a crewmember’s performance. Also, understanding that fellow crewmembers may react differently to the same stressor is important and can help a flight crewmember control a situation that can quickly get out of hand if an individual is having a negative reaction.
3 Causes of Stress
Any activity, event or other stimulus that causes stress is referred to as a stressor. These can be internal (cognitive or physical) or external (environmental) to the individual.
3.1 Environmental/physical stressors
Physical stressors are underlying conditions that can either be internal to the body (e.g., pain, hunger, lack of sleep, exhaustion), or external environmental factors (e.g., noise, pollution, over-crowding, excess heat). The common factor among all of these stressors is that they all create a physically uncomfortable environment that can cause stress. Stress is not solely dependent on the intensity of a stimulus but also on the duration of exposure. For example, a low-pitched but persistent noise can cause as much stress as a sudden loud noise.
In the cockpit some common environmental/physical stressors are:
- Persistent radio communication noise
- Sudden alarms or warning horns
- Uncomfortable temperature
- Engine and system noise
- Cramped workspace
- Air quality
- Lighting conditions.
Aircraft manufacturers have been addressing many of these stressors to reduce the physical stress on flight crews.
3.2 Work-related stressors
Stress in the workplace can come from a variety of sources besides physical stimuli. For example, pressure from management to ensure on-time performance can sometimes conflict with demands for safe service. The reason such situations cause so much stress is that there is often a threat of an unpleasant outcome no matter what decision the pilot makes. If the pilot presses on to complete everything on time and satisfy management, there is a risk of an accident or incident. If the pilot chooses to ensure maximum safety and causes a delay, there is the threat of sanction from management.
Both situations can lead to high levels of stress.
Other work-related stressors, such as work underload or overload, crew conflicts and role ambiguity, can lead to high levels of stress. Also, stress transfers can occur when one person dealing with a stressful situation creates a stressful situation for those around him or her.
The job strain model developed by Dr. Robert A. Karasek (Figure 1) addresses the level of strain a person will likely experience based on job demands and the degree of decision latitude a person has on the job. The model predicts that the highest stress and stress-related health problems will occur for jobs with high demands and low decision latitude.
3.3 Personal stressors
Personal stressors include events occurring outside of the workplace that can affect an individual’s performance at work. Many people believe that they can separate their private and working lives and keep one from affecting the other. However, this is not possible. Preoccupation with personal problems consumes mental resources and distracts a person from the task at hand. Also, because stress is cumulative, personal stressors can make what would normally be a small stressor into a bigger problem.
Events such as loss of a relative, injury or illness can greatly affect stress levels and consequently behavior at work. Smaller frustrations such as computer or car trouble can also act as stressors. These small stressors can add up over time and greatly affect crewmember performance.
4 How Stress Develops and the Types of Stress
People react differently when exposed to a stressor. Reactions differ because people process and interpret information differently. How a person processes information can greatly affect what type of stress he or she experiences.
4.1 The transactional model of stress
The first thing that a person automatically does when faced with a stressful event is to appraise the situation. The appraisal and stress process is outlined below in the model of stress developed by Lazarus and Folkman (Figure 2).
One conducts a primary appraisal to determine the level of danger, the potential pain, loss or discomfort and the amount of effort that will have to be exerted to handle the situation. If no threat is perceived, no stress is felt.
If a threat is perceived, an individual goes through a secondary appraisal process in which he or she examines his or her perceived available resources to cope with the problem. How a person appraises the situation is a function of past experience and perceived ability to cope with the stressor. A person selects the “best” solution, which is usually the least dangerous, most likely to succeed and the one for which the person has the most appropriate skills. If a person perceives that he or she can cope with the stress, positive stress is experienced. A perceived inability to fully cope with the situation leads to negative stress.
Figure 2. Transactional model of stress (Lazarus and Folkman, 1984).
A pilot’s reaction to stress is dependent on the interaction between the capabilities of the person involved and the external situation being faced. Factors include:
- Pilot’s physiological state at the time - health, fatigue, lack of sleep, etc.
- Stressor itself - Intensity (strength), duration and predictability (the less predictable the more stressful it becomes)
- Personal evaluation of the stressor
- Personality - People who are impatient, irritable, competitive, driven, have fast speech, and/or are achievement-oriented are more likely to have intense stress reactions. Also, those people with low self-esteem are likely to have strong stress reactions
- Ability and willingness of others to give support, both social and practical - confidence in the other crewmember’s abilities reduces stress levels.
4.2 Types of stress
Several types of stress have been identified. The primary types of stress are:
- Eustress (positive stress) motivates a person to cope with stressors and allows a person to perform effectively and may even increase performance. Eustress generally occurs when an individual perceives that he or she has the ability to effectively cope with a stressor.
- Distress (negative stress) occurs when stimulation is excessive and causes fear of the situation, panic, anxiety or agitation. Distress usually results in poorer performance and can be dangerous for flight safety.
- Anxiety is stress related to an unforeseen or imagined threat. It is caused by the anticipation or perception that something dangerous, unpleasant or harmful may be about to occur, and the individual is fearful that he or she will not be able to cope with the event.
- Remembered Stress is triggered by an event that reminds an individual of a past experience that caused extreme stress or harm. The actual stress-causing agent may not be present, but the memory still causes the body to arouse the nervous system, and the stress related to the effects of the unpleasant episode are experienced again.
4.3 Duration of stress
The persistence and/or duration of a stressful event or situation define whether the stress is acute or chronic. Physical and mental reactions to these types of stress can be very different.
- Acute Stress is caused by stressors that occur for very short periods of time. Usually, an individual is able to resolve the stressful situation and return to a normal mental and physiological state. Acute stress can be positive, but extremely high levels of over-arousal for short durations can lead to exhaustion.
- Chronic Stress is caused by a constant stream of demands, risks, pressures and threats that go on for significantly long periods of time. Chronic stress slowly drains mental and physical resources and leaves a sense of hopelessness or inability to cope. If prolonged, it can have very serious health implications such as the onset of a stroke, heart disease or even heart attack. In extreme cases it has led to suicide. The most dangerous aspect of chronic stress is that because it is prolonged, an individual may stop noticing its effects even though the negative effects are still taking place. It becomes a familiar sensation that is accepted as the status quo, and a person may not take any actions to cope with the stress, which can lead to further problems.
5 Symptoms of Stress and Effects on Performance
An individual’s physical and psychological reactions to stress can greatly affect performance. Physical and psychological reactions are closely intertwined, and one can profoundly influence the other.
5.1 Physiological and psychological reactions to stress
Stress is a process of adaptation. Without any stress at all, the body would be too relaxed and passive to cope with any serious or demanding situations. When stressful situations are detected, the nervous system is stimulated to a higher level of alertness.
This heightened level of alertness is normally characterized by an increased release of adrenaline (also called epinephrine) into the bloodstream. Epinephrine is a hormone that initiates many bodily responses including stimulation of heart action and increases in blood pressure, metabolic rate and blood glucose concentration. Adrenaline is the most potent stimulant of the nervous system and helps the body function faster and in a more alert way that helps a person to cope with more demanding situations or those that require quick reactions.
However, there can be an over-release of adrenaline if a situation is perceived as too demanding. The resulting effect is over-stimulation, which can cause a person to reach a point of being overwhelmed by the situation and feeling unable to cope. The highest level of over-stimulation is commonly referred to as panic, and a person who panics is often unable to respond in any useful manner.
The body starts exhibiting visible signs of stress when adrenaline levels in the bloodstream exceed certain levels. Recognizing these signs in both oneself and others is one of the first steps in effectively managing stress. The most commonly observed symptoms are:
- Cardiovascular: increased pulse rate, high blood pressure, chest pains
- Respiratory: shortness of breath, hyperventilation, dizziness
- Gastrointestinal: loss of appetite, gas pains, indigestion, diarrhea, nausea
- Others: headaches, muscular tension, sleep disturbances, general weakness
- Emotional: anger, guilt, mood swings and low self-esteem, depression
- Irritable temper
- Loss of interest
- Loss of control
5.2 Effects of stress on physical and mental performance
As previously mentioned, excessive stress levels reduce performance. Increases in over-stimulation is generally proportional to decreases in performance. Some of the typical effects that occur in stressful situations include:
- Difficulty concentrating and reduced vigilance - easily distracted
- Errors, omissions, mistakes, incorrect actions, poor judgment and memory
- Tendency to cut corners, skip items and look for the easiest way out
- Either slowness (due to lack of interest) or hyperactivity (due to adrenaline)
- Focusing on easily manageable details while ignoring serious threats
- Tendency to pass responsibility on to others
- Fixation on single issues or even a mental block
- Unwillingness to make decisions - decisions are postponed or take longer to make
- Fewer plans and backup plans are made
- Increase in risk-taking leading to an increase in the number of violations, especially when frustrated with failures
- Excessively hurried actions - Due to adrenaline and alertness level, there is a tendency to act very quickly even when there is no time pressure. Hurried actions increase the chance of errors.
In cases of significantly high stress a flight crewmember will often:
- Return to old procedures that may no longer be applicable
- Use non-standard phraseology when communicating
- Return to the use of one’s native language
- Look for items in a place where they used to be but are no longer located.
5.3 Other effects - interpersonal relations in the cockpit
As one might expect, since stress affects behavior it also affects relationships between people. In the cockpit, this situation can be critical. Two negative interpersonal conflicts that can develop involve aggressive behavior or withdrawal.
Aggression is a natural consequence of high adrenaline and alertness levels. Aggressiveness can be mild or more pronounced and is usually verbal in nature. Aggressive behaviors can be directed toward ATC, the other pilot, the crew or anyone else who can be blamed for what is happening.
Withdrawal occurs when a person has feelings of incompetence and results in an inability to face the situation at hand. The individual will usually not put forth any effort and “gives up.” All tough decisions are left to the other crew member, and the withdrawing crewmember will often follow instructions without thought or question.
6 Managing Stress
As already discussed, stress is a mechanism that can sometimes over-stimulate the nervous system, making it hard to address serious threats to flight safety. It is difficult to control stress reactions, but it is not entirely impossible. Coping efforts can be focused toward the stressor or the emotions that arise as a result of stress, but the most effective strategy is to deal with both the stressor and its emotional impact. Reducing the negative emotional impact of the stressor removes many of the barriers that obstruct the problem-solving thought processes.
6.1 Recognizing a stressful condition
The first step in effective stress management is to train yourself to be able to recognize the symptoms that signal the onset of stress before stress levels get too high. Some common signals of stress include:
- Physical signs: cold, sweaty hands, headache, tension
- Behavioral changes: irritability, anger, hurriedness, fixation
- Speech patterns: fast, irregular, non-standard phrases, voice tone or loudness
6.2 Dealing with stress in flight
It is important to know how to deal with acute stress taking place during flight and chronic stress that may have been around for an extended period of time. Reactive and preventative measures are available to deal with both acute and chronic stress. Very often the preventative measures help to improve the reactive coping techniques. For example, practicing a certain emergency technique or making good backup plans are both preventive and make it much easier to deal with an emergency. In general, preparation and practice create competence and confidence and greatly reduce stress levels.
Some stressors that are faced in flight cannot be avoided. The best way of coping with such stressors involves a combination of preparation (preflight) and in-flight corrective actions.
1. Preparation. Knowledge of techniques for dealing with certain flight situations that are not frequently encountered and the ability to apply these techniques proficiently is crucial for safety.
2. Anticipation. It is good to anticipate possible scenarios and threats that could arise during the flight even if they are very unlikely to happen. This will reduce the surprise factor if something does happen.
3. Planning. Anticipating what might happen is not enough. It is important that once all reasonable scenarios and threats are identified, a sound plan for dealing with them is made on the ground before flight. This further increases preparedness.
4. Communication. Briefings both on the ground before the flight and in flight are critical. Letting other crewmembers know what the plans are will ensure that everyone knows what to do and that no one will be surprised or will do anything that is contrary to the planned action.
5. Use of Resources. Make the best use of all available resources. This includes careful distribution of tasks in the cockpit and other resources, such as onboard equipment and ATC, which can always help by providing information and advice that will help you deal with the situation and reduce stress levels.
6. Crew Resource Management (CRM). Share tasks to avoid work overload. If you are overloaded with too many tasks, do not avoid asking for assistance. Learn to recognize the symptoms of stress, not only in yourself, but also in other crewmembers. Provide advice or assistance when necessary. A good cabin atmosphere with plenty of humor always helps.
7. Time Management. Always do things in advance whenever possible. Do not leave tasks until the last moment (e.g., asking ATC for clearances). Whenever possible, buy yourself more time to analyze and solve a situation properly in order to avoid rushed actions.
Should you still be faced with a totally unexpected stressful situation despite all your careful planning and anticipation, the keys are to recognize the symptoms, remain calm and buy yourself as much time to think as possible. By understanding stress mechanisms, you can control negative emotions resulting from stress such as irritation, nervousness and anxiety, and attempt to solve the problem in the most logical and safe way possible.
6.3 Dealing with long-term and chronic stress
No matter how much you try to avoid certain stressful situations in flight, there will always be personal or other stressors, some outside your control, that will affect you. Some of these stressors may be chronic. The most basic elements of coping with these chronic stress issues are:
- Taking care of the physical causes of stress - These includes ensuring you get enough sleep, eat properly and exercise. Hunger and fatigue are some of the most obvious stressors, and their effects are well-known. Climbing stairs is a very good way of eliminating excess toxins in the body, and swimming helps restore equilibrium to the nervous system. Both of these activities usually can be carried out in hotels during stopovers, eliminating residual effects of stress before the next flight.
- Continuous Professional Training - Training ensures currency and competence in all standard and emergency operating procedures.
- Social Interaction - It is not good to allow personal problems and worries to build up. Communicating them with others is very important as it offers partial relief and also because people may be able to offer help and advice.
- Workload - Do not allow yourself to take on too many tasks and responsibilities (both work and non-work related) that can cause work overload. It is important to learn to say “no” when asked to do too many tasks.
7 Summary of Key Points
The following key points should be emphasized:
- Stress is a physiological and cognitive response to stressors that generates alertness
- In excess, stress results in a large number of side effects - both physical and mental
- Stress is triggered by stressors that are either immediate threatening/challenging situations or long-term background issues
- The response to a stressor depends on both its intensity and the amount of exposure time
- Stress can be acute or chronic
- Chronic stress can become so routine that you lose awareness of its presence, yet it still carries its harmful effects
- The best way to reduce stress is to:
- Learn to recognize the symptoms
- Prepare and plan by maintaining currency and proficiency through regular training
- Take care of the physical aspect: food, sleep and exercise
- Keep workload under control, communicate and ask for help
8 Associated Flight Operations Briefing Notes
Situational Examples: Stress was a factor in most of the listed situational examples, including the following:
9 Additional Reading Material/Websites References
- Flight Safety Foundation
- Cabon, P; Mollard, R; Bougrine, S; Coblentz, A, and Speyer J.J. Coping with Long- Range Flying - Recommendations for Crew Rest and Alertness Airbus Industrie ed, Blagnac - France (1995)
- Airbus Industrie Getting to Grips with Fatigue and Alertness Management -publication, Issue II July 2004, available as a book or on CD-ROM.
- Selye, H. The Stress of Life.; McGraw-Hill, New York, USA (1976)
- Spielberger, C. Understanding Stress and Anxiety ; New York, USA, (1979)
- Lazarus, R. S. and Folkman, S. Stress, Appraisal and Coping. New York: Springer Publishing Company (1984)
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