Influence of long-lasting physical work upon mental and psychomotor performance in relation to the time of day.

Twenty three women and 20 men (19--27 year old) were tested at different time of day using battery of psychological tests. All subjects were tested every 2 hours continuously for many hours. Between consecutive tests they worked on a bicycle ergometer (series A) or rested in sitting position (series B). The influence of three following factors upon performance level was considered: circadian fluctuations, duration of the experiment, and physical effort preceding testing. Positive influence of physical effort has been shown in psychomotor tests and negative one in mental tests which was especially pronounced at night or in the morning after night work.