Introduction to Glider Flying > Introduction to Glider Flying > Medical Factors Associated with Glider Flying > Fatigue

Fatigue is frequently associated with pilot error. Some of the effects of fatigue include degradation of attention and concentration, impaired coordi-nation, and decreased ability to communicate. These factors can seriously influence your ability to make effective decisions. Physical fatigue can result from sleep loss, exercise, or physical work. Factors, such as stress and prolonged perform-ance of cognitive work, can result in mental fatigue.

Fatigue falls into two broad categories; acute fatigue (short-term) and chronic fatigue (long-term). Acute fatigue is short-lived 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 eight hours of sound sleep ordinarily cures this condition.

A special type of acute fatigue, skill fatigue has two main effects on performance:
• Timing disruption—You appear to perform a task as usual, but the timing of each component is slightly off. This makes the pattern of the operation less smooth, because you perform each component as though it were separate, instead of part of an integrated activity.
• Disruption of the perceptual field—You concentrate your attention upon move-ments or objects in the center of your vision and neglect those in the periphery. This may be accompanied by loss of accuracy and smoothness in control movements.

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

Acute fatigue can be prevented by a proper diet and adequate rest and sleep. A well-balanced diet prevents the bodyfrom having to consume its own tissues as an energy source. Adequate rest maintains the body’s store of vital energy.

Sustained psychological stress accelerates the glandular secretions that prepare the body for quick reactions during an emergency. These secretions make the circulatory and respiratory systems work harder, and the liver releases energy to provide the extra fuel needed for brain and muscle work. When this reserve energy supply is depleted, the body lapses into chronic fatigue.

Chronic fatigue, extending over a long period of time, usually has psychological roots, although an underlying disease is sometimes responsible. Continuous high stress levels, for example, can produce chronic fatigue. Chronic fatigue is not relieved by proper diet and adequate rest and sleep, and usually requirestreatment from your doctor. You 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 prob-lems and generalized aches and pains through-out
the body. When the condition becomes serious enough, it can lead to emotional illness.

If you find yourself suffering from acute fatigue, stay on the ground. If you become fatigued in the cockpit, no amount of training or experience can overcome the detrimental effects. Getting ade-quate rest is the only way to prevent fatigue from
occurring. You should avoid flying when you have not had a full night’s rest, when you have been working excessive hours, or have had an espe-cially exhausting or stressful day. If you suspect you are suffering from chronic fatigue, consult your doctor.