Effects of normobaric hypoxic endurance training on fatigue in patients with multiple sclerosis: a randomized prospective pilot study

BACKGROUND: Fatigue is one of the most frequent symptoms in patients with multiple sclerosis (MS), causing a major impact on quality-of-life. Non-pharmacological intervention strategies involve physical activity, which has been shown to reduce fatigue. Training under normobaric hypoxic conditions is thought to improve the response to endurance training and may, therefore, have an additional benefit over normoxic training conditions in MS patients. OBJECTIVE: To compare the effects of endurance training under hypoxic and normoxic conditions on fatigue, mobility and spasticity in patients with MS during inpatient rehabilitation. METHODS: Thirty-nine patients with MS were assigned within a randomized prospective longitudinal pilot study to (1) a routine clinical rehabilitation program, (2) a routine clinical rehabilitation program + normoxic endurance training and (3) a routine clinical rehabilitation program + hypoxic endurance training for 14 days. Fatigue (WEIMuS and MFIS), spasticity (MSSS-88) and walking endurance (6MinWT) were assessed at days 0, 7 and 14. RESULTS: Fatigue scores improved significantly in all groups, but these improvements were reached faster in the groups which additionally received endurance training (normoxic p = 0.004; hypoxic p = 0.002). Spasticity scores were significantly lower in endurance training groups at the end of the study compared to baseline (normoxic p = 0.048, hypoxic p = 0.012), while only the hypoxic group increased significantly in 6MinWT (p = 0.001). CONCLUSIONS: Our findings demonstrate that endurance training provides substantial benefit to neurological rehabilitation programs. Endurance training under hypoxic conditions could positively influence walking endurance within a 2-week training intervention and warrants further investigations.