Search

BACKGROUND: Persons with Multiple Sclerosis have elevated resting serum lactate concentrations compared to healthy controls (HC). OBJECTIVE: To evaluate lactate concentrations during acute exercise and/or following training in MS compared to HC. METHODS: In this retrospective study, blood lactate concentrations (mmol/l) originating from two previous studies were analyzed. Lactate concentrations originated from acute submaximal (MSsubmax; HC, n = 11; MS, n = 32) or maximal (MSmax; HC, n = 20; MS, n = 24) exercise tests and following a 24-week mild to moderate intensity (MSsubmax, n = 12) or 12-week high intensity interval (MSmax, n = 13) exercise intervention. RESULTS: Under submaximal conditions in MS and compared to HC, lactaterest (MS: 2.7±0.6 vs HC: 2.3±0.7 was significantly (p < 0.05) elevated. After 24 weeks of mild-to-moderate-intensity exercise training and compared to PRE-values, lactatebout2 (2.5±0.7 vs 3.4±1.1) significantly (p < 0.05) decreased during submaximal testing in MSsubmax. Under maximal conditions, lactatestart (2.3±1.0 vs 1.7±0.9) was significantly (p > 0.05) elevated in MS. Twelve weeks of high intensity interval training did not improve this (p > 0.05). CONCLUSIONS: Under the conditions of this retrospective analysis we conclude that lactate concentrations during acute submaximal and maximal exercise in persons with MS are similar compared to healthy controls. Moderate intensity exercise therapy appeared to improve lactate accumulation but high intensity exercise therapy did not. [ABSTRACT FROM AUTHOR]

Purpose: High-intensity concurrent training positively affects cardiovascular risk factors. Because this was never investigated in multiple sclerosis, the present pilot study explored the impact of this training on cardiovascular risk factors in this population. Methods: Before and after 12 weeks of high-intense concurrent training (interval and strength training, 5 sessions per 2 weeks, n = 16) body composition, resting blood pressure and heart rate, 2-h oral glucose tolerance (insulin sensitivity, glycosylated hemoglobin, blood glucose and insulin concentrations), blood lipids (high- and low-density lipoprotein, total cholesterol, triglyceride levels) and C-reactive protein were analyzed. Results: Twelve weeks of high-intense concurrent training significantly improved resting heart rate (−6%), 2-h blood glucose concentrations (−13%) and insulin sensitivity (−24%). Blood pressure, body composition, blood lipids and C-reactive protein did not seem to be affected. Conclusions: Under the conditions of this pilot study, 12 weeks of concurrent high-intense interval and strength training improved resting heart rate, 2-h glucose and insulin sensitivity in multiple sclerosis but did not affect blood C-reactive protein levels, blood pressure, body composition and blood lipid profiles. Further, larger and controlled research investigating the effects of high-intense concurrent training on cardiovascular risk factors in multiple sclerosis is warranted. Implications for rehabilitation: High-intensity concurrent training improves cardiovascular fitness. This pilot study explores the impact of this training on cardiovascular risk factors in multiple sclerosis. Despite the lack of a control group, high-intense concurrent training does not seem to improve cardiovascular risk factors in multiple sclerosis. [ABSTRACT FROM AUTHOR]

Introduction: The prevalence of impaired glucose tolerance (IGT) is higher in persons with multiple sclerosis (MS) compared to healthy controls, indicating metabolic deficits that may increase comorbidity. In other populations, IGT can, at least partly, be reversed by intense physical exercise, but this is never investigated before in MS. Aim: To investigate the effect of high intensity aerobic and resistance training on glucose tolerance and skeletal muscle GLUT4 content in MS. Methods: Thirty-four persons with MS (aged 45 ± 3 years, EDSS 2.5 ± 1.07) were randomized into three groups, including a (1) sedentary control group (SED, n= 11), (2) 12-week high intensity interval plus resistance training group (HITR,n= 12), or (3) 12-week high intensity continuous aerobic training plus resistance training group (HCTR, n = 11). Before and after 12 weeks, glucose tolerance and skeletal muscle GLUT4 content were determined by an oral glucose tolerance test and analysis of a m.vastus lateralis biopsy, respectively. Results: There were no significant changes for subjects of SED. From pre- to post-intervention, total area under the glucose curve (tAUC) decreased significantly in both HITR (-6.9 ± 6.2%) and HCTR (-11 .0 ± 7.7%) (P < 0.05). Insulin tAUC decreased (-12.3 ± 14.7%) within HCTR and muscle GLUT4 content increased (+6.6 ± 4.5%) in HITR. Conclusion: Twelve weeks of high intensity aerobic exercise in combination with resistance training improved glucose tolerance in persons with MS. [ABSTRACT FROM AUTHOR]

In the treatment of multiple sclerosis (MS), exercise training is now considered a cornerstone. However, most clinicians tend to focus on neurologic deficits only, and thus prefer to prescribe rehabilitation programs specifically to counteract these deficits. However, the present comprehensive review shows that patients with MS (pwMS) also experience significant muscular, cardiac, ventilatory and metabolic dysfunction, which significantly contribute, next to neurologic deficits, to exercise intolerance. In addition, these anomalies also might increase the risk for frequent hospitalization and morbidity and can reduce life expectancy. Unfortunately, the impact of exercise intervention on these anomalies in pwMS are mostly unknown. Therefore, it is suggested that pwMS should be screened systematically for muscular, cardiac, ventilatory and metabolic function during exercise testing. The detection of such anomalies should lead to adaptations and optimisation of exercise training prescription and clinical care/medical treatment of pwMS. In addition, future studies should focus on the impact of exercise intervention on muscular, cardiac, ventilatory and metabolic (dys)function in pwMS, to contribute to improved treatment and care. [ABSTRACT FROM AUTHOR]

Background: In persons with MS (pwMS), a lower cardiopulmonary fitness has been associated with a higher risk for secondary disorders, decreased functional capacity, symptom worsening and reduced health-related quality of life. Objective: To investigate the association between disease severity and cardiopulmonary fitness. Methods: Data from cardiopulmonary exercise tests, previously conducted in three different countries, were pooled. The association between disease severity (Expanded Disability Status Scale (EDSS)) and cardiopulmonary fitness (peak oxygen uptake (VO2peak)) was adjusted for age, sex and the country of origin. Results: The combined sample comprised 116 ambulant pwMS having a mean (± SD) EDSS score of 2.7 ± 1.3. There was a significant correlation (r = -0.418, p < .01) between VO2peak and EDSS. A multiple regression model (R2 = 0.520, p < .01) was constructed to describe VO2peak (mL∙kg−1∙min−1); VO2peak = 36.622 − 5.433 (Sex (1=men)) – 0.124 (Age) − 2.082 (EDSS) + 2.737 (Belgium) + 8.674 (Denmark). Conclusion: There was a significant association between disease severity and cardiopulmonary fitness. The close relation between cardiopulmonary fitness and chronic conditions associated with physical inactivity, suggest a progressive increase in risk of secondary health conditions in pwMS [ABSTRACT FROM AUTHOR]

Despite frequent muscle strength or muscle oxidative capacity (based on exercise-onset oxygen uptake [VO2] kinetics) assessments in patients with multiple sclerosis, the impact of time of day on these parameters is often not taken into account. Based on observations in healthy subjects, it remains to be studied whether muscle strength, and/or exercise-onset VO2 kinetics, varies between the morning and the afternoon in patients with multiple sclerosis. In this prospective observational pilot study, walking capacity, exercise-onset VO2 kinetics, isometric knee extension/flexion strength (dynamometry), and self-reported fatigue were measured in 11 patients with multiple sclerosis (age, 51.8 ± 9.3 yrs; body mass index, 24.7 ± 5.1 kg/m²; Expanded Disability Status Scale, 3.5 ± 1.4; 3 men) in the morning and 5 hrs later (afternoon). In the afternoon, self-reported fatigue (1.9 ± 0.9 cm) and muscle strength (knee extension peak torque at 45 degrees, 84 ± 26 Nm) were significantly different (P < 0.05), than in the morning (self-reported fatigue, 1.2 ± 0.9 cm; knee extension peak torque at 45 degrees, 93 ± 32 Nm), but walking capacity and exercise-onset VO2 kinetics were similar at these two time points (P > 0.05). Consistent with observations in healthy subjects, muscle strength varies between the morning and the afternoon in patients with multiple sclerosis, under the conditions of the present study. These findings suggest that muscle strength assessments should be conducted at similar or nearly similar times of the day to minimize diurnal variation in these measures and hence insure correct interpretation. [ABSTRACT FROM AUTHOR]

BACKGROUND: 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). OBJECTIVE: To study the impact of whole-body cooling on exercise-onset VO2 kinetics in pwMS. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To explore the etiology of exercise intolerance in patients with MS, it is analyzed whether a disturbed cardiac autonomic control could be observed during exercise testing in patients with MS, and is related to exercise tolerance. PATIENTS AND METHOD: From 26 MS patients and 15 healthy subjects, exercise-onset (first 20 and 60 seconds) and -offset (1-minute recovery) HR change was determined during a 6-minute constant-load exercise bout on bike. Blood lactate, HR, oxygen uptake, expiratory volume and perceived exertion were assessed during exercise, and compared between groups. In 15 MS patients, a 6-min walking test was executed. RESULT: Twenty-second exercise-onset HR increase was significantly smaller in MS patients (14 ± 7 bts/min) vs. healthy subjects (20 ± 8 bts/min, p < 0.05), and independently related to MS and age in total group (p < 0.05). Sixty-second exercise-onset and -offset HR changes were not different between groups, nor independently related to MS presence (p > 0.05). A significant correlation was found between 20-second exercise-onset HR increase and walking capacity in MS patients (r = 0.64, p < 0.01). CONCLUSION: In MS patients, the early increase in heart rate during endurance exercise is significantly slowed, indicating a disturbed cardiac autonomic control, and is related to exercise tolerance. [ABSTRACT FROM AUTHOR]