Following a cardiac event, there is a decrease in myocardial function which may reduce an individual's usual physical activity and may contribute to the perception of fatigue. Although perception of fatigue and decreased ability to perform physical activity are common responses in patients who have coronary disease (CAD), very few studies have been conducted in this area.

The purpose of this study was to: (1) evaluate the perception of fatigue in coronary artery patients; (2) explore the relationship between perceived fatigue and physiological parameters; and (3) determine changes in perception of fatigue and physical capacity over 12 weeks of rehabilitation. The subjects included 34 patients who had experienced a recent MI, had anginal symptoms, had angioplasty procedure, or bypass surgery.

A time-series, repeated-measures design was used over a three-month period. All subjects underwent exercise tests prior to and at the eighth week of the rehabilitation program. Exercise capacity was calculated for each subject according to his/her maximal walking speed and steepness of the slope during treadmill exercise tests. Four questionnaires were employed in this study: Fatigue/Stamina Scale, the Duke Activity Status Index, the Profile of Mood States, and the Beck Depression Inventory (BDI). These questionnaires were completed by each subject prior to, at eight weeks, and at the completion of the rehabilitation program.

The results indicated that fatigue scores decreased throughout the rehabilitation program (p = 0.03). Exercise capacity and daily activity performance improved (p $<$ 0.0001). Changes in fatigue scores were unrelated to exercise training intensity. Significant predictor variables for fatigue were: daily activity level, medications, and BDI score. This study suggests that fatigue perceived by CAD patients is associated with both psychologic and physiologic responses to their cardiac events. Results of this study provide a foundation for further study of the concept of fatigue in CAD patients.