Article

OBJECTIVE: To explore the etiology of exercise intolerance in patients with MS,
it is analyzed whether a disturbed cardiac autonomic control could be observed
during exercise testing in patients with MS, and is related to exercise
tolerance. METHOD: From 26 MS patients and 15 healthy subjects,
exercise-onset (first 20 and 60 seconds) and -offset
(1-minute recovery) HR
change was determined during a 6-minute constant-load exercise bout on bike.
Blood lactate, HR, oxygen uptake, expiratory volume and perceived exertion were
assessed during exercise, and compared between groups. In 15 MS patients, a 6-min
walking test was executed. RESULT: Twenty-second exercise-onset HR increase was
significantly smaller in MS patients (14 +/- 7 bts/min) vs. healthy subjects (20
+/- 8 bts/min, p < 0.05), and independently related to MS and age in total group
(p < 0.05). Sixty-second exercise-onset and -offset HR changes were not different
between groups, nor independently related to MS presence (p > 0.05). A
significant correlation was found between 20-second exercise-onset HR increase
and walking capacity in MS patients (r = 0.64, p < 0.01). CONCLUSION: In MS
patients, the early increase in heart rate during endurance exercise is
significantly slowed, indicating a disturbed cardiac autonomic control, and is
related to exercise tolerance.

Langue : ANGLAIS