Whole-body cooling does not compromise muscle oxidative capacity in subjects with multiple sclerosis

Whole-body cooling improves exercise tolerance in patients with multiple sclerosis (pwMS). To be able to exercise at greater intensities and/or for longer durations with whole-body cooling, it should be examined whether this compromises skeletal muscle oxidative capacity (assessed by exercise-onset VO2 kinetics).

To study the impact of whole-body cooling on exercise-onset VO2 kinetics in pwMS.

From 12 pwMS (EDSS 3.5 ± 1.5) and 12 healthy age, BMI, and gender-matched subjects exercise-onset VO2 kinetics (mean response time [MRT]) and body temperature were determined under normothermic and hypothermic (pre-exercise 60-min whole-body cooling) conditions during submaximal exercise testing (two 6-min constant-load exercise bouts). Moreover, heart rate, blood lactate content, expiratory volume and ratings of perceived exertion (RPE) were assessed during exercise.

Exercise heart rate (-7 ± 6 beats/min) and end-exercise body temperature (-0.9 ± 0.5°C) was significantly lower in hypothermic vs. normothermic conditions in both populations (p < 0.05). In pwMS exercise RPE was lower in hypothermic vs. normothermic condition (p = 0.056). No significantly different MRT was found between normothermic vs. hypothermic conditions in both populations.

Lowering body temperature prior to endurance exercise does not affect muscle oxidative capacity in pwMS, but lowers RPE, thus making it possible to prescribe exercises of greater intensity and/or longer duration.