Abstract
This study investigated cardiorespiratory responses and rating of perceived exertion
(RPE) during prolonged walking and running exercise performed at the walk-run transition
speed (WRTS) in untrained healthy elderly men. 20 volunteers (mean±SE, age: 68.4±1.2
yrs; height: 170.0±0.02 cm; body mass: 74.7±2.3 kg) performed the following bouts
of exercise: a) maximal cardiopulmonary exercise test (CPET); b) specific protocol
to detect WRTS; and c) two 30-min walking and running bouts at WRTS. Expired gases
were collected during exercise bouts via the Ultima CardiO2 metabolic analyzer. Compared to walking, running at the WRTS resulted in higher oxygen
uptake (>0.27 L·min−1), pulmonary ventilation (>7.7 L·min−1), carbon dioxide output (>0.23 L·min−1), heart rate (>15 beats·min−1), oxygen pulse (>0.88 15 mL·beats−1), energy expenditure (>27 kcal) and cost of oxygen transport (>43 mL·kg−1·km−1·bout−1). The increase of overall and local RPEs with exercise duration was similar across
locomotion modes (P<0.001). In all participants, %HRR and %VO2R throughout walking and running bouts were around or above the gas exchange threshold.
In conclusion, elderly men exhibited higher cardiorespiratory responses during 30-min
bouts of running than walking at WRTS. Nevertheless, walking corresponded to relative
metabolic intensities compatible with preservation or improvement of cardiorespiratory
fitness and should be preferable over running at WRTS in the untrained elderly characterized
by poor fitness and reduced exercise tolerance.
Key words
walk-run transition speed - oxygen uptake reserve - heart rate reserve - perceived
exertion - gas exchange threshold - exercise prescription