Complaints of fatigue: related to too much as well as too little external stimulation?

Fatigue has been acknowledged as a widespread problem associated with a variety of factors. In the present paper, we attempt to explain fatigue complaints on the basis of Pennebaker's (1982) "competition of cues" notion. Competition of cues suggests that both extremely low and extremely high levels of external stimulation in daily life may be related to relatively higher frequencies of complaint. The dimensional structure of external stimulation is first explored and then the shape of the relation between external stimulation (i.e., stimuli perceived in daily life) and fatigue was studied in a sample of 777 general-practice patients. Other risk factors for fatigue and moderating factors are also taken into consideration. Results show that quantity and quality of external stimulation can be distinguished. Both high quantity (high "experienced overload") and low quality (low "attractiveness of external stimulation") are related to higher fatigue frequencies. "Experienced overload" is a particularly strong predictor, in addition to "perceived health" of fatigue complaints. It is concluded that the "quality-quantity model for understanding fatigue" proposed here highlights psychological factors important for any theoretical framework of fatigue.