Article

Low physical activity levels in persons with multiple sclerosis (MS)
may reduce skeletal muscle oxidative capacity. Rehabilitation strategies might be
altered by a measure of capacity that did not require invasive techniques or
maximal exercise testing. For this purpose, we measured exercise onset and offset
oxygen uptake (Vo(2)) kinetics during endurance exercise. OBJECTIVE: This study
compared exercise-onset and -offset Vo(2) kinetics in mildly affected persons
with MS with healthy matched participants. METHODS: From 38 MS patients who had a
mean Expanded Disability Status Scale of 3.1 and 16 healthy participants,
exercise-onset and -offset Vo(2) kinetics (mean response time [MRT]) were
determined during two 6-minute submaximal bouts of exercise separated by a
6-minute recovery interval. Blood lactate, heart rate, expiratory volume, and
Borg ratings of perceived exertion were assessed during exercise and compared
between groups. Relationships between clinical characteristics and MRT were
assessed. RESULTS: During exercise, blood lactate, heart rate, and expiratory
volume did not differ between groups (P > .05), but exercise-onset MRT was
significantly slower in MS versus healthy participants (P = .007). Exercise-onset
MRT was independently related to having MS (P = .02). Exercise-offset MRT was not
different between groups or was independently related to having MS (P > .05). No
independent relationships between clinical characteristics of MS and
exercise-onset or -offset MRT were found. CONCLUSIONS: Exercise-onset Vo(2)
kinetics during submaximal endurance exercise are significantly slowed in mildly
disabled persons with MS, suggesting low skeletal muscle oxidative capacity.
Using mean response time testing, rehabilitation interventions for this reduction
in exercise capacity can be assessed and targeted.

Langue : ANGLAIS