Inter-effort recovery hypoxia did not mitigate acute treadmill effects in people with Parkinson's disease

Hypoxia exposure has been suggested as a complementary strategy for gait rehabilitation in Parkinson's disease (PD). However, due to the significant decrease in oxygen availability, the practical use of hypoxia may mitigate the positive effects of other interventions on gait in people with PD, such as treadmill-based exercise. Therefore, this study investigated the effects of inter-effort recovery hypoxia (IEH) during treadmill sessions on gait in people with PD.

Nineteen individuals with PD underwent this randomized, double-blind, controlled trial. The experimental session consisted of two periods of hypoxia or placebo exposure (2 × 10 min), interspersed with treadmill exercise at participant's self-selected gait velocity (2 × 10 min). The hypoxia generator (Everest Summit II) was set to deliver either 13.6 % O₂ during IEH or 20.9 % O₂ during the control condition (CON). Gait was assessed at a self-selected speed before and immediately after the session (GAITRite).

Higher hypoxia doses were observed throughout the IEH (median [IQR]: 4.4 [1.7]%.h) compared to CON (0.2 [0.3]%.h) (p = 0.001; large effect size). Gait velocity and step length improved following the experimental sessions (p < 0.005; moderate to large effect sizes), with no significant differences between IEH and CON (p > 0.302; small effect sizes).

IEH did not negatively affect the acute impact of treadmill exercise on gait in people with PD. These findings address the existing literature, demonstrating that the hypoxia exposure approach can be used during exercise sessions without adverse effects on gait in people with PD.