Cardiopulmonary responses to eccentric and concentric resistance exercise in older adults

Background: in older ambulatory persons, exercise strategies that are expected to generate beneficial muscle adaptations with low cardiopulmonary demands are needed. Objective: we hypothesised that eccentric resistance exercise would be less demanding on the cardiovascular and pulmonary systems than bouts of concentric resistance exercise. Design: the effects of eccentric and concentric resistance exercise were compared during leg squats at a submaximal intensity known to increase muscle mass. Subjects: 19 older persons (15 women/four men, age 65 +/- 4 years) and 19 young reference controls (10 women/nine men; age 25 +/- 2 years) were enrolled. Methods: participants completed eccentric-only and concentric-only exercise bouts 5-7 days apart. Results: cardiovascular and pulmonary measures were collected from subjects during bouts consisting of three sequential sets of 10 repetitions at 65% of their voluntary concentric 1-repetition maximum force (68 +/- 16 kg for older participants and 94 +/- 36 kg for young participants). Peak heart rate (119 +/- 10 versus 155 +/- 16 b.p.m.), systolic blood pressure (129 +/- 18 versus 167 +/- 14 mmHg), cardiac index (7.8 +/- 2.0 versus 9.2 +/- 1.5 l/min/m(2)) and expired ventilation (20.5 +/- 5.7 versus 29.8 +/- 9.1 l/min) were significantly lower during eccentric than during concentric bouts in the older subjects, respectively (P < 0.001 for all comparisons). Similarly, peak heart rate, systolic blood pressure, cardiac index and expired ventilation were significantly lower during eccentric bouts in the young control subjects. Conclusions: eccentric resistance exercise produced less cardiopulmonary demands and may be better suited for older persons with low exercise tolerance and at risk of adverse cardiopulmonary events.