The effect of exercise and induced expectations on visceral perception in asthmatic patients

It is assumed that visceral perception of the asthmatic patient is not only influenced by the physiological response itself but also by cognitions, i.e. specific illness related attitudes and expectations. Thirty-two adult asthmatics were studied in a 2 X 2-factorial design to examine the effect of physical exercise due to an ergometer capacity test (set at a load of 40 and 80 watt respectively) and induced expectations about the consequences of this task on broncho-constriction. Two sets of instructions were used to induce anticipations of harmful and non-harmful consequences respectively. The following dependent variables were registered: airways resistance, skin resistance and visceral perception (rating of physiological changes). Before the experiment the habitual way of reacting to asthma-relevant cues in each subject was assessed. Only small effects of the different ergometer loads on physiological responding and no effects of the experimental variables on visceral perception were found using an analysis of variance approach. A covariance analysis, however, using the trait variable as covariate, demonstrated that the induced 'harmful' anticipation significantly intensified the perception of visceral changes and even had some influence on asthma-relevant physiological responding.