Strength training and hemodynamic responses to exercise

Sixty-two older adults (68.4+/-6 years) were randomized into a control group (n=16), low-intensity exercise group (n=22, LEX; 50% 1-repetition maximum; 13 repetitions per exercise), or a high-intensity exercise group (n=24, HEX; 80% 1-repetition maximum; eight repetitions per exercise) group. Subjects trained for 24 weeks, performing 1 set for each of 13 exercises. Subjects performed a graded exercise test (GXT) at baseline and after 24 weeks of strength training. Heart rate, systolic, and diastolic blood pressures were measured at rest, during the GXT and 1, 3, and 5-min post-GXT. Mean arterial pressure was also calculated. Post-training, time to peak systolic and diastolic blood pressures and heart rate was increased in the LEX and HEX groups by 22.9% and 44.5%, respectively (p<0.05). Diastolic blood pressure, heart rate, and mean arterial pressure during the GXT were significantly decreased (p<0.05) in the HEX group following training. Post-GXT heart rate was lower in the HEX and LEX groups compared to control (p<0.05) indicating a more rapid recovery. Resistance exercise prolongs the onset of peak cardiovascular responses, decreases the cardiovascular response to exertion, and improves recovery from maximal exertion.