Effects of resistance training on cardiovascular responses to lower body negative pressure in the elderly.

The purpose of the present study was to determine whether resistance training alters the cardiovascular responses to submaximal lower body negative pressure (LBNP) in the elderly. Twenty-one subjects were randomized into a control (C: n=10; 70 +/- 3 years, mean +/- SD) or a resistance training (TR: n=11; 67 +/- 7 years) group. Subjects in the TR underwent 12 weeks of training consisting of three sets of 8-12 contractions at approximately 60-80% of their initial maximal one repetition, three times per week, on 10 different machines. Before (Pre) and after (Post) training, all subjects underwent exposures of LBNP of -10, -20 and -40 Torr and muscle biopsy sampling at the vastus lateralis. TR increased (P< or =0.05) knee extension (Pre=379 +/- 140 N, Post=534 +/- 182 N) and chest press (Pre=349 +/- 137 N, Post=480 +/- 192 N) strength. Neither body weight nor percentage body fat were altered (P >0.05) by training. Resistance training increased (P< or =0.05) cross-sectional area in both Type I (4203 +/- 1196 to 5248 +/- 1728 microm2) and Type II (3375 +/- 1027 to 4286 +/- 1892 microm2) muscle fibres. Forearm blood flow, forearm vascular conductance, mean arterial pressure, and heart-rate responses to LBNP were not altered by the training. These data suggest that the cardiovascular responses of elderly to LBNP are unaffected by 12 weeks of whole-body resistance training despite increases in muscle strength and size.

RCT Entities:   Population Interventions Outcomes