Medicine & Science in Sports & Exercise:
Annual Meeting Abstracts: F-45 - Free Communication/Slide: Chronic Disease and Special Populations
Austin, Stephen R.1; Jenkins, Nina1; Polichnowski, Aaron J.1; Lobeck, Lorri J.2; Bobholz, Julie A.2; Ng, Alexander V. FACSM1
1Marquette University, Milwaukee, WI.
2Medical College of Wisconsin, Milwaukee, WI.
Aquatic compared to land exercise may result in improved exercise tolerance in persons with multiple sclerosis (MS). Water temperatures of ∼83° F are considered optimal for exercise in MS while warmer temperatures of ∼ 90° F are thought to result in decreased exercise tolerance and worsening of function. PURPOSE: To determine physiological and neurocognitive effects of exercising in water of different temperatures in MS. METHODS: Six (5F) MS subjects, reporting temperature sensitive fatigue, performed 20 mins. of treadmill exercise at a VO2 corresponding to a rating of perceived exertion (RPE) of 10–11 (Borg, 20 pt) on land (L) and in waistdeep water (Aquacizer) at 77 (C), 83 (M), and 93°F (H). Target VO2 was determined on an initial visit. VO2 (Cortex, MetaLyser 3B), body core temperature (TC, HQInc), and heart rate (HR) were measured continuously. RPE was obtained every min. Before and after each exercise test and a 20 min. attention control (AC, reading), cognitive and physical function were assessed with the Symbol Digit Modalities Test (SDMT), paced auditory serial addition test (PASAT), word generation test (WORD), 9-hole peg test, and 25 ft walk test. Fatigue after each test was assessed with a 10 pt scale. Tests were assigned randomly with >24 hrs between tests. Analyses were by rmANOVA, or paired t-tests. Sig. was p<0.05. Results = mean ± SD. RESULTS: Subject characteristics: age = 43 ± 3 yrs, EDSS = 2.5 (mode). There were no differences in VO2 between tests (∼ 0.99 ± 0.07 l O2 min−1, p>0.2). TC increased in all conditions and increased less in C compared to both L and H (C = 0.32 ± 0.11, L = 0.55 ± 0.18, H = 0.59 ± 0.08 °F, p<0.03). HR increased from similar baselines in all conditions. Average HR was less in C compared to L (C = 98 ± 9, L = 108 ± 16 bt/min, p = 0.03). Average RPE was similar among groups (∼ 11 ± 2 units, p >0.3). Fatigue tended to increase less in C compared to L (C = 0.8 ± 0.2 units, L = 1.6 ± 2.2 units, p = 0.06). Thus, C offered physiological advantages over L and H. For cognitive measures, both SDMT (pre = 64.2 ± 9, post = 60.2 ± 11, p = 0.03) and WORD (pre = 30 ± 17, post = 27 ± 16, p = 0.04) worsened after AC. PASAT improved after C (pre = 53 ± 6, post = 58 ± 2, p = 0.03). No differences due to exercise or temperature were noted in 9-hole peg test or 25 ft walk test. Thus, compared to control (i.e. AC), aerobic exercise maintains some cognitive functions and C exercise may improve cognitive function in MS. CONCLUSIONS: Acute exercise in C water can result in improved exercise tolerance and cognitive function in MS compared to L or other water temperatures. Exercise in water as warm as 93° F does not appear to be detrimental to persons with MS. Supported in part by the National Multiple Sclerosis Society.