Henry W. Mertens

The Effects of Age, Sleep Deprivation, and Altitude on Complex Performance

This research examined the potential interactions of age, sleep deprivation, and simulated altitude (gas mixtures). Healthy men aged from 30 to 39 years (N = 16) and from 60 to 69 years (N = 14) participated in the four possible combinations of two altitudes (ground versus 3810 m) and two sleep conditions (sleep permitted/sleep deprived). Sleep deprivation involved loss of one nights sleep. Following training, complex (time-shared) performance was tested during three-hour sessions in the morning and afternoon of each of four test days. Tasks included monitoring of warning lights and meters, mental arithmetic, problem solving, target identification, and tracking. Workload was varied within each hour by varying the tasks performed simultaneously. There was a significant interaction of sleep deprivation and altitude that was enhanced by increasing workload. When the subjects were sleep deprived, performance was significantly lower in general, and the greatest decrement in performance occurred at altitude. The performance of older subjects tended to be lower and more affected by increases in workload than was that of younger subjects, but the detrimental effects of sleep deprivation or the combination of sleep deprivation and altitude did not appear to interact with age.