Sleep and Fatigue
Fatigue slows reaction time, reduces concentration and leads to errors of attention. The most common causes are insufficient rest, lack of sleep, and overexertion. Fatigue can also be aggravated by other stresses such as business pressures and financial or family problems as well as common illnesses, such as anaemia, sleep apnoea, influenza, and head colds. Pilots should be aware of the subtle effects that acute or chronic fatigue can have on motor skills and judgement, and avoid flying when either of these are present. Pilots should also practice good sleep hygiene to prevent fatigue. Pilots who find that they are often troubled by fatigue or drowsiness, even while not flying, should see their healthcare provider for a thorough medical evaluation. Boredom and fatigue aggravate each other. One method of overcoming boredom is to keep busy by making frequent groundspeed and fuel consumption checks, and staying mentally active. Planning for diversion to alternates or studying relevant airfield charts are also helpful.
Fatigue falls into two broad categories: acute and chronic. Acute fatigue is short term and is a normal occurrence in everyday living. It is the kind of tiredness people feel after a period of strenuous effort, excitement, or lack of sleep. Rest after exertion and 8 hours of sound sleep ordinarily cures this condition. Acute fatigue has many causes, but the following are among the most important for the pilot:
- Mild hypoxia (oxygen deficiency)
- Physical stress
- Psychological stress
- Depletion of physical energy resulting from psychological stress
- Sustained psychological stress
Chronic fatigue, extending over a long period of time, usually has psychological roots, although an underlying disease is sometimes responsible. Continuous high-stress levels produce chronic fatigue. Chronic fatigue is not relieved by proper diet and adequate rest and sleep and usually requires treatment by a physician. An individual may experience this condition in the form of weakness, tiredness, palpitations of the heart, breathlessness, headaches, or irritability. Sometimes chronic fatigue even creates stomach or intestinal problems and generalized aches and pains throughout the body. When the condition becomes serious enough, it leads to emotional illness.
If suffering from acute fatigue, stay on the ground. If fatigue occurs in the flight deck, no amount of training or experience can overcome the detrimental effects. Getting adequate rest is the only way to prevent fatigue from occurring. Avoid flying without a full night’s rest, after working excessive hours, or after an especially exhausting or stressful day. Pilots who suspect they are suffering from chronic fatigue should consult a physician.
REFERENCES AIM AIR 3.10 Fatigue