Usefulness of self-efficacy in predicting overexertion during programmed exercise in coronary artery disease

Overexertion during group jogging was evaluated in relation to self-perceived functional capacity and ability to self-monitor exertional heart rate in 40 men, mean age 55 +/- 9 years, with documented coronary artery disease. Patients' confidence in their ability to jog various distances was measured with a jog self-efficacy (SE) scale before a group exercise program was begun. Depression, type A personality, and performance of symptom-limited treadmill exercise were also assessed. Later, each patient was monitored with ambulatory (Holter) electrocardiography during programmed group jogging. Ambulatory monitoring disclosed significant noncompliance with exercise prescriptions: 33% of patients exceeded their prescribed range of 70% to 85% of maximal treadmill heart rate for at least 10 minutes of the 20-minute exercise bout. Another 25% spent 10 minutes or longer exercising below the prescribed range. Pretest jog SE predicted the number of minutes patients exercised above or below the prescribed intensity, but depression, type A and treadmill performance measures did not. Self-monitoring accuracy (the amount of agreement between exercise heart rate recorded by the electrocardiogram and by the patient) was also related to the number of minutes patients exercised outside the prescribed range. Comparison of SE and self-monitoring accuracy variables revealed that "overachievers" were patients who overestimated their ability to jog, while "underachievers" were those who overestimated their heart rate during exercise. Self-perceptions and self-monitoring skills appear to be important independent predictors of behavioral compliance to exercise guidelines.