SELF RATINGS OF PERFORMANCE, FEELINGS OF FATIGUE AND MOTIVATION WERE OBTAINED FROM 12 ARMY TRUCK DRIVERS WHO WERE REQUIRED TO DRIVE THE SECOND VEHICLE OF A TWO VEHICLE CONVOY FOR ELEVEN HOURS ON EACH OF FOUR CONSECUTIVE DAYS ON EITHER AN EARLY OR LATE SHIFT. DRIVERS AT THE END OF THE LATE SHIFT REPORTED SYMPTOMS OF PERFORMANCE DETERIORATION, DROWSINESS AND EXHAUSTION AND WERE MORE INCLINED TO WANT TO STOP DRIVING. THESE SYMPTOMS WERE SLIGHTLY MORE CHARACTERISTIC OF THE OLDER DRIVERS FOR WHOM SERUM CORTISOL LEVELS WERE ALSO RELATIVELY ELEVATED. THE DISCREPANCY BETWEEN THESE FINDINGS AND THE MARKED ABSENCE OF ANY INCREASE IN OBJECTIVE PERFORMANCE RISKINESS REPORTED EARLIER WAS INTERPRETED TO BE DUE TO THE DRIVERS' COMPENSATORY ADJUSTMENT IN FOLLOWING DISTANCE WHEN FATIGUED.(Author/publisher).
Abstract