Purpose: Heat sensitivity is a common contraindication in people with Multiple Sclerosis (pwMS), and physical fatigue is one of the most frequently reported symptoms that can affect quality of life. Increases in body temperature may exacerbate fatigue and heat-related symptoms. Decreasing body temperature via cooling devices may mitigate disease symptoms and improve physical abilities and quality of life. This study evaluates the effects of a cooling vest with sham condition on walking capacity using a commercially-available cooling vest specifically designed for pwMS. Methods: A counter-balanced, cross-over design was used to assess the effects of a cooling vest (CryoVest Comfort, CryoInnov, France) (COLD) from a menthol-induced sham condition (CON) on ground walking time to exhaustion (Tex, s) and distance at exhaustion (Dex, m) in ambulatory pwMS. Secondary outcomes were heart rate (HR, bpm), thermal sensation (Tsens), skin chest (Tchest) and back (Tback) temperature. Results: Ten females with Multiple Sclerosis (59 ± 9 years, EDSS 3.0–5.5) participated to the study. During COLD, pwMS walked significantly longer (1896 ± 602 vs. 1399 ± 404 s, p < 0.001) and farther (1879 ± 539 vs. 1302 ± 318 m, p < 0.001) than CON. Importantly, Tsens and HR at exhaustion were not significantly different between conditions, although Tchest (− 2.7 ± 1.8 °C, p < 0.01) and Tback (− 3.9 ± 1.8 °C, p < 0.001) were lower at volitional fatigue during COLD. Conclusion: The lightweight cooling vest improved total walking time and distance in heat-sensitive pwMS. These physiological improvements were likely due to feeling perceptually cooler in the COLD trial, compared to the corresponding point of fatigue in the CON condition.
