Heart rate and oxygen consumption during mental arithmetic, a video game, and graded static exercise.

Heart rate, oxygen consumption, and respiratory activity were recorded while 18 young male subjects performed a stressful mental arithmetic task and played a video game. Measurements were also taken while subjects undertook a graded static leg lifting exercise. Physiological activity increased as an orderly function of exercise workload. For each subject, heart rate was plotted against oxygen consumption over the various exercise loads. Knowing oxygen consumption during the psychological tasks, these regression equations allowed the prediction of heart rate, and thus the computation of “additional” heart rate as the difference between actual and predicted heart rate. Overall predicted heart rate values were significantly less than the values actually recorded during the psychological tasks. However, whereas mental arithmetic was associated with “additional” heart rates of the same order as those observed in earlier research using graded dynamic exercise, the video game elicited decidedly less “additional” heart rate in the present case. The explanation for this lay in the regression lines; static exercise was characterized by heart rate-oxygen consumption regressions which were much steeper in terms of slope, as well as somewhat lower in terms of intercept, than those observed with graded dynamic exercise.