Abstract
The purpose of this study was to examine the effects of a 6-month cycling aerobic
exercise intervention on cardiorespiratory fitness and the dose-response
relationship in community-dwelling older adults with mild-to-moderate
Alzheimerʼs dementia. The FIT-AD trial was a single blind, 2-parallel group,
pilot randomized controlled trial. The aerobic exercise group participated in a
6-month, thrice weekly, moderate-vigorous intensity cycling intervention while
control group performed stretching. Cardiorespiratory fitness was evaluated by
peak oxygen consumption from cardiopulmonary exercise test and peak walking
distance from the shuttle walk test and 6-minute walk test. Aerobic exercise
dose was calculated using the novel heart rate physical activity score. The
aerobic exercise group significantly increased peak oxygen consumption
(1.28 ml/kg/min; p=0.03) in subgroup who
achieved maximal criteria on cardiopulmonary exercise test. Changes in peak
oxygen consumption and peak walking distance on the shuttle walk and 6-minute
walk tests did not significantly differ between aerobic exercise and stretching
groups. Notably, the aerobic exercise dose was strongly and significantly
correlated to change in peak oxygen consumption (r=0.60; n=16;
p=0.01), in subset who met maximal test criteria. Emphasis on exercise
dose is needed in aerobic exercise programs to maximize cardiorespiratory
fitness gains in persons with mild-moderate Alzheimerʼs dementia.
Key words
cardiorespiratory fitness - Alzheimerʼs disease - cognition - dementia - exercise
- exercise dose
