Article

BACKGROUND: To walk a given distance older persons consume more metabolic energy
than younger adults across all speeds. As physical activity interventions improve
a variety of physical performance measures in older persons, including walking
speed, in this study we hypothesized that the improvement of walking speed might
be associated with the reduction of the metabolic cost of walking and we tested
our hypothesis in a selected sample of older patients receiving cardiac
rehabilitation. METHODS: In 120 patients (88 men and 32 women, mean age 74.1
years+/-SD 5.0) we assessed energy expenditure during the 6-min Walk Test (6mWT)
before and after the rehabilitation using a portable system for direct
calorimetry. RESULTS: On the 6mWT performed after the rehabilitation patients
significantly increased total energy expenditure (28.0 kcal+/-SD 8.3 vs. 25.7
kcal+/-SD 7.6, p<0.001), the distance walked (398 m+/-SD 93 vs. 343 m+/-SD 95,
p<0.001) and, consequently, walking speed (1.11 m/s+/-SD 0.26 vs. 0.95m/s+/-SD
0.26, p<0.001) while the metabolic cost of walking, i.e. the amount of energy
used to move a body mass of 1 kg for a distance of 1m, was significantly reduced
(1.00 cal/kg/m+/-SD 0.19 vs. 1.11 cal/kg/m+/-SD 0.32, p<0.001). CONCLUSIONS: In
older patients receiving cardiac rehabilitation the improvement of walking speed
is associated with the improvement of walking economy. This might be a
contributory factor to the favourable effects of physical activity interventions
on physical performance measures.
CI - Copyright A(c) 2011 Elsevier B.V. All rights reserved.

Langue : ANGLAIS