Substrate use by elderly men during walking and low-sit cycling

To compare the cardiovascular and metabolic responses to different exercise modes, ten healthy, elderly men (aged 71.4 +/- 4.2 yr) walked and cycled in the low-sit position for 15 min each at 70% of peak heart rate. Fifteen minutes of recovery separated the exercise bouts. Analysis of expired air was used to calculate oxygen consumption (VO2), respiratory exchange ratio (RER), O2 pulse, total energy expenditure (TE) and fat oxidation (FO). Ratings of perceived exertion (RPE) were recorded for both legs and breathing. Each subject maintained similar heart rates on each of the exercise bouts (mean = 108 beats.min-1). No significant differences were found in VO2, O2 pulse and TE. RPE's were significantly lower during walking than cycling (P < 0.05). FO was 42% higher during walking than cycling (P < 0.05). These results suggest that although the cardiovascular response and TE use during these two modes are similar, elderly men burn more fat during walking than low-sit cycling.