INTERNATIONAL MARITIME ORGANIZATION
GUIDELINES ON FATIGUE
Introduction
Fatigue can be defined in many ways. However, it is generally described as a state of feeling tired, weary, or sleepy that results from prolonged mental or physical work, extended periods of anxiety, exposure to harsh environment, or loss of sleep. The result of fatigue is impaired performance and diminished alertness.
The effects of fatigue are particularly dangerous in the shipping industry. The technical and specialized nature of this industry requires constant alertness and intense concentration from its workers. Fatigue is also dangerous because it affects everyone regardless of skill, knowledge and training.
Effectively dealing with fatigue in the marine environment requires a holistic approach. There is no one-system approach to addressing fatigue, but there are certain principles (e.g. lifestyle habits, rest, medication, workload, that must be addressed in order to gain the knowledge and the understanding to manage this human element issue.
Objective
The human element, in particular fatigue, is widely perceived as a contributing factor in marine casualties. The Exxon Valdez, one of the worst maritime environmental disasters in the century, is one of the many mishaps where fatigue was identified as a contributing factor.
To assist in the development of a marine safety culture by addressing the issue of fatigue, the International Maritime Organization (IMO) has develop practical guidance to assist interested parties to better understand and manage the issue of “fatigue” .
The philosophy behind the development of the guidance was not to develop new information but rather assemble what already exists, in a useful format, for transmission to those parties who have a direct impact on ship safety.
The outline of the information is related to the potential dangers associated with fatigue and ultimately the effects on the health and safety of the personnel working on ships. The guidelines contain information on the symptoms and causes of fatigue, and address solutions to combat fatigue to improve the associated health problems and help prevent a fatigue-related accident from occurring.
Foreward
The Guide lines on Fatigue contain practical information that can assist interested parties (crew members and training institutions) to better understand and manage fatigue.
The guidelines provide information on the potential dangers of fatigue and ultimately the effect on the health and safety of the personnel working on ships. The guidelines contain information on the symptoms and causes of fatigue, and address solutions to combat fatigue in order to reduce associated health problems and prevent fatigue-related accidents from occurring.
The guidelines have been divided into nine modules, as follows and the Module 9 contains practical information intended for tugboat personnel. It recommended that they become familiar with other modules.
1. How can you recognize fatigue in yourself and others?
You may exhibit one or more changes in behavior when experiencing fatigue. However, one very important fact to remember is that people who are fatigue have very difficult time recognizing the signs of fatigue within themselves. It is difficult for a number of reasons, but largely because fatigue can effect your ability to make judgments or solve complex problems. The following list describes how fatigue affects your mind and body; you may recognize some of these changes in others (with time, you may learn to identify some within yourself).
A Physical
• Inability to stay awake (an example is head nodding or falling asleep against you will);ç
• Difficulty with hand-eye co-ordination skills (e.g. switch selection);
• Speech difficulties (it may be slurred, slowed or garbled);
• Heaviness in the arms and legs or sluggish feeling;
• Decreased ability to exert force while lifting, pushing o pulling;
• Increased frequency or dropping objects like tools or parts;
• Non-specific physical discomfort;
• Headaches;
• Giddiness;
• Heart palpitation/irregular heartbeat;
• Rapid breathing;
• Loss of appetite;
• Insomnia;
• Sudden sweat fits;
• Leg pains or cramps;
• Digestion problems;
B Emotionally
• Increased willingness to take risks;
• Increased willingness and ant-social behavior;
• Needless worry;
• Reduce motivation to work well;
• Increased mood changes (e.g. irritability, tiredness and depression)
C Mentally
• Poor judgment of distance, speed, time, etc.;
• Inaccurate interpretation of a situation (e.g. focusing on a simple problem or failing to anticipate the gravity of the situation or failing to anticipate danger);
• Slow or no response to normal, abnormal o emergency situations;
• Reduce attention span;
• Difficulty concentrating and thinking clearly;
• Decrease in ability to pay attention;
Whenever alertness is affected by fatigue, your performance will be handicapped.
It is important that you notify your supervisor when recognize that you or other crew members are fatigued. It is important to have an open communication between you and your supervisor regarding fatigue prevention and detection.
2. What can cause fatigue?
Fatigue may be caused and/or made worse by one or combination things such as:
• Lake of sleep
Only sleep can maintain or restore your performance level. When you do not get enough, sleep, fatigue will set in and your alertness will be impaired;
• Poor quality of sleep
Fatigue may be caused by poor quality of sleep. This can occur when you are unable to sleep without interruptions or you are unable to fall asleep even though your body tells you do;
• Insufficient rest time between work periods
Apart from sleep, rest (taking a break) between work periods can contribute to restoring your performance levels. Insufficient rest periods or postponing assigned rest times (to finish the job early) can cause fatigue;
• Poor quality of rest
Disturbances while resting such as being woken up unexpectedly, or call (during por operations), or unpredictable working hours (when arriving in port) can cause fatigue;
• Stress
Stress can be caused by personal problems (family), problems with other shipmates, long work hours, work in general, etc. A build up of stress will cause pr increase fatigue;
• Boring and respective work
Boredom can cause fatigue. You may become bored to the point of fatigue, when your work is too easy, respective and monotonous and/or bodily movement is restricted;
• Noise or Vibration
Noise or vibration can affect your ability to sleep/rest, and it can affect your level of physical stress, thus causing fatigue;
• Ship’s movement
The ship’s movement affects your ability to maintain physical balance. Maintaining balance requires extra energy, which can then cause fatigue. A ship’s pitching and rolling motions mean you might have to use 15-20% extra effort to maintain your balance.
• Food, (timing, frequency, content and quality)
Refined sugars (sweets, doughnuts, chocolates, etc) can cause your blood sugar to rise rapidly to a high level. The downside of such short-term energy is that a rapid drop in blood sugar can follow it. Low blood sugar levels can cause weakness, instability, difficulty in concentrating and in extreme cases, unconsciousness. Eating large meals prior to sleep period may disrupt you sleep.
• Medical conditions and illness
Medical conditions (i.e. heart problems) and illness such as the common cold can cause fatigue. The effect depends on the nature of the illness or medical condition but also the type of work being carried out. For example, common colds slow response time and hand-eye co-ordination performance.
• Ingesting chemicals
Alcohol, caffeine and some over-counter medications disrupt sleep. Caffeine consumption can also causes other side effects such as hypertension, headaches, mood swings or anxiety.
• Jet lag
Jet lag occurs following long flights through several time zones. It is a condition that causes fatigue in addition to sleep-deprivation and irritability- it is easier to adjust to time zones while crossing from east to west as opposed to west to east. The greatest difficulty in adjustment results from crossing 12 time zones, the least from crossing one time zone. Our bodies adjust at the rate of approximately 1 h per day.
• Excessive workload
Working consistently “heavy” workloads can cause fatigue. Workload is considered heavy when one works excessive hours or performs physically demanding or mentally stressful tasks. Excessive work hours and fatigue can result in negative effects such as the following.
- Increased accident and fatality rates;
- Increased dependence upon drugs, tobacco or alcohol;
- Poor quality and disrupted sleep patterns;
- Higher frequency of cardiovascular, respiratory or digestive disosders;
- Increased risk of infection, and
- Loss of appetite.
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3. How can you protect yourself from the onset fatigue?
A Sleep issues
Sleep is the most effective strategy to fight fatigue. Sleep loss and sleepiness can degrade every aspect of a person’s performance: physical, emotional and mental. To satisfy the needs of you body, experts agree that you should acquire the following:
• Deep sleep;
• Between 7 to 8 h of sleep per 24-hour day;
• Uninterrupted sleep;
Here is some general guidance on developing good sleep habits:
• Develop and follow a pre-sleep routine to promote sleep at bedtime (example are a warm shower or reading calming material);
• Make the sleep environment conductive to sleep (a comfortable bed, a dark, quiet and cool environment encourages sleep);
• Ensure that you will have no interruptions during your extended period of sleep;
• Satisfy any other physiological need before trying to sleep (examples are if hungry or thirsty before bed, eat, or drink lightly to avoid being kept awake by digestive activity and always visit the toilet before trying to sleep);
• Avoid alcohol and caffeine prior to sleep (keep in mind that coffe, tea, colas, chocolate and some medications, including cold remedies and aspirin, amy contain alcohol and/or caffeine). Avoid caffeine at least six hours before bedtime;
• Considerer relaxation techniques such as meditation and yoga, which can also be of great help if learn properly.
B Rest issues
Another important factor that can affect fatigue and performance is rest. Rest, apart from sleep, can be provided in the form of breaks or changes in activities. Rest pauses or breaks are indispensable as a physical requirement if performance is to be maintained. Factors influencing the need for rest are the length and intensity of the activities prior a break or a change in activity, the length of the break, or the nature or change of the new activity.
C Guidelines on maintaining performance
Here are some general guidelines that can help you maintain perdormance:
• Get sufficient sleep, especially before any period when you anticipate that you will not get adequate sleep;
• When you sleep, make it a long period of sleep;
• Take strategic naps;
• Take breaks when schedule breaks are assigned;
• Develop and maintain good sleep habits, such are a pre-sleep routine (something that you always do get you ready to sleep);
• Monitor your hours of works and rest when opportunity arises;
• Eat regular, well-balanced meals (including fruit and vegetables, as well as meat and starches);
• Exercise regularly.
4. What can mitigate the effects of fatigue?
The most powerful means of relieving fatigue is to proper sleep to rest when appropriate. However, a number of things have been identified as potentially providing some short-term relief. Note, however, that these countermeasures may simply just mask the symptoms temporally –the fatigue has no been eliminated.
• An interesting challenge, an exciting idea, a change in work routine or anything else that is new and different well keep you awake.
• Changing the order of activities, where personnel are assigned tasks that include variety in the nature of tasks, can be beneficial in breaking up job monotony. Mixing tasks requiring high physical or mental work with low-demand tasks can be beneficial.
• Bright lights, cool dry air, music and other irregular sounds can increase alertness.
• Caffeine (encountered in coffee and tea, and to a lesser extent in colas and chocolate) may combat sleepiness in some people for short periods. However, regular usage over time reduces its value as a stimulant and may make you more tired and less able to sleep.
• Any type of muscular activity helps to keep you alert, running, walking, stretching or even chewing gum can stimulate our level of alertness;
• Conversation cal help you stay awake;
• Controlled, strategic naps can improve alertness and performance (the most effective length of time for a nap is about 20 min).
Strategic napping
Research has identified “strategic napping” as a short-term relief technique to help maintain performance levels during long periods of wakefulness. The most effective length of time for a nap is about 20 min. this means that if you have the opportunity to nap you should take it. However, there are some drawbacks associated with napping. One potential drawback is that naps longer than 30 min will cause sleep inertia. Where situational awareness is impaired (grogginess and/or disorientation for up 20 min after waking. A second I that nap may disrupt later sleeping periods (you may not be tired when time comes for an extended period of sleep).
5. What can be done to reduce crew fatigue on board tugboats?
There are a number of steps that can be taken to prevent fatigue. Many of the measures that reduce fatigue are unfortunately beyond a single person’s ability to influence, such as voyage scheduling, ship design, work scheduling. Steps such as the following /where applicable) are important for the prevention of fatigue on board ships, and are within the tugboat personnel’s ability and implement:
• Ensuring the compliance with maritime regulations concerning minimum hours of rest and/or maximum hours of work;
• Creating an open communication environment (e.g. by making it clear to the crew members that is important to inform supervisors when fatigue is impairing their performance and that there will be no recriminations for such reports).
• Scheduling drills in a manner that minimizes the disturbance of rest/sleep periods;
• Establishing on-board management techniques when scheduling shipboard work and rest periods, watchkeeping practices and assignment of duties in a more efficient manner;
• Assigning work by mixing up tasks to break up monotony and combining work that requires high physical or mental demand with low-demand tasks (job rotation);
• Scheduling tasks with potential hazards for daytime hours, when appropriate;
• Emphasizing the relationship between work and rest periods to ensure that adequate rest is received by promoting individual record keeping of hours rested or worked;
• Ensuring that shipboard conditions, within the crew’s ability to influence, are maintained in a good state (such as maintaining the hearing, ventilation and air-condition (HVAC) on schedule, replacing light-bulbs, and contending with the sources of unusual noise at the first opportunity);
• Establishing shipboard practices for dealing with fatigue incidents and learning from them (as part of safety meeting);
• Increasing awareness of the long-term health benefits of appropriate lifestyle behavior (e.g. exercise, relaxation, nutrition, smoking and alcohol consumption).
Recopilado
Capt
Guillermo Parra Avello
Nov - 2009
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