The Effects of Pericooling on Six Minute Walk Test Performance in Persons with Multiple Sclerosis

Background: Persons with MS (pwMS) are limited in their mobility due to thermosensitivity.  Exercising at a sufficient volume and intensity to increase mobility can result in increased core temperatures and worsening of symptoms.  The use of cooling garments to lower core temperature has been found to allow persons pwMS to exercise for longer periods. Previous studies have relied on cooling for an extended period of time prior to activity  (precooling) to achieve improved exercise performance.  Cooling during the performance itself, or pericooling, may allow for similar performance gains to be realized without spending the time needed for precooling. 

Objectives: The purpose of this study was to examine the effects of pericooling on 6-minute walk test (6MWT) performance in pwMS.  It was hypothesized that pwMS would have better 6MWT performance while wearing a cooling vest as compared to an uncooled condition.  If our hypothesis were correct, it would suggest that pwMS could achieve improved exercise performance without needing precooling.

Methods: A randomized crossover design was used. Patients were randomized into cooled or uncooled conditions. Cooled subjects would perform a 6MWT donning a commercially available cooling vest immediately prior to the walk. Walks would be performed once a week for three weeks. Total 6MWT distance as well as minute-by-minute distance was recorded. Fatigue during the walk was measured using the Visual Analog Scale of Fatigue. Uncooled subjects would perform the identical protocol without a cooling device.  Following the 3 walks in one condition, subjects would undergo a 2-week washout period and then repeat the same protocol in whatever condition they did not experience initially.

Results: Six females (x̅ age = 51.33 years) with mild MS (x̅ EDSS  = 2.67) completed the study.  A repeated-measures MANOVA showed that wearing the cooling vest resulted in walking significantly farther in the cooled condition (x̅   = 1257.13’, SD = 375.50) than in the uncooled condition (x̅ =1164.56’, SD = 302.81), F(1,17) = 4.63, p = .046.There were no significant differences in minute-by-minute walking distances nor in VAFS scores between the two conditions.

Conclusions: The cooled condition resulted in significantly longer 6MWT distances than did the uncooled condition in 6 females with mild MS. As most studies of cooling in MS utilize cooling prior to an exercise activity, these results indicate an alternative and less time-consuming means of achieving the beneficial effects of cooling.