PHYSIOLOGICAL-RESPONSES TO WEIGHT LIFTING IN CORONARY-ARTERY DISEASE

This study assesses the safety of and physiologic responses to maximal repetition, dynamic, resistive weight lifting at 40, 60, 80 and 100% of maximal voluntary contraction compared with aerobic exercise using a maximal treadmill exercise test. Twelve men with coronary artery disease exercised to fatigue at 4 stations (overhead press, biceps curl, quadriceps extension and supine press). The electrocardiogram was monitored continuously. Heart rate and systolic and diastolic blood pressures (by sphygmomanometer) were measured at rest and during peak exercise. No symptoms or electrocardiographic evidence of ischemia occurred with weight lifting, whereas 5 of 12 patients had ischemic ST-segment depression (greater-than-or-equal-to 1 mm) with the treadmill. No significant ectopy occurred with either activity. Mean peak heart rates with all lifts were less (range 74 to 92 beats . min-1; p less-than-or-equal-to 0.05) than with the treadmill (157 beats . min-1). Peak systolic blood pressures were similar, whereas peak diastolic blood pressures were greater with all lifts (range 93 to 117 mm Hg; p less-than-or-equal-to 0.05), except 100% maximal contraction biceps curl and quadriceps extension, than with the treadmill (79 mm Hg). Peak rate pressure product was greater with the treadmill than with all lifts (p less-than-or-equal-to 0.05). Diastolic time interval from the electrocardiograph was shorter with the treadmill (0.154 second) than with all lifts (range 0.323 to 0.448 second; p less-than-or-equal-to 0.05). Diastolic pressure-time index was greater with all lifts than with the treadmill (p less-than-or-equal-to 0.05). The ratio of the diastolic pressure-time index to rate pressure product, an indirect estimate of the balance between myocardial oxygen supply and demand, was greater for all lifts (range 0.214 to 0.262 second; p less-than-or-equal-to 0.05) than for the treadmill (0.074 second). Thus, estimated myocardial oxygen supply-to-demand balance appears more favorable with maximal repetition weight lifting than with maximal treadmill exercise.