Experimental manipulation of aerobic fitness and the response to psychosocial stress: heart rate and self-report measures.

To determine whether aerobic fitness training alters response to psychosocial stress, 38 males were randomly assigned to either aerobic, anaerobic (weight-lifting), or waiting-list control groups. Experimental groups met three to four times per week in 1-hr sessions aimed at improving either cardiovascular endurance or muscular strength. Aerobic fitness level, heart rate and subjective response to laboratory psychosocial stress, and self-reports of daily stress, coping resources and psychologic symptoms were assessed prior to and following 10 weeks of training. Although posttraining fitness measures confirmed the effectiveness of aerobic training, no group differences were seen on laboratory or self-report measures. However, for aerobic trainers alone, fitness improvement tended to correlate with faster heart rate recovery following psychosocial stress. Fitness improvement was not correlated with any other psychologic changes. This experiment provides only modest support for the hypothesis that aerobic training alters response to psychosocial stress. It is suggested that future work on the psychologic effects of aerobic fitness explore the contribution of training parameters as well as subject characteristics.