Aerobic Fitness and Instrumental Activities of Daily Living in People with Multiple Sclerosis: A Cross-sectional Study

Relationship between VO2peak, VO2 Recovery Kinetics, and Muscle Function in Older Adults

INTRODUCTION

The efficiency of the cardiovascular system to recover following an exercise bout is measured by oxygen (VO2) recovery kinetics. In older adults with a chronic disease, a higher aerobic capacity (VO2peak) and faster VO2 recovery kinetics are associated with higher muscle strength and physical capacity. Yet, this relationship in healthy older adults remains unclear. The aim of this cross-sectional study was to determine whether a higher VO2peak and faster VO2 recovery kinetics are associated with higher muscle strength and physical performance in healthy community-dwelling older adults.

METHODS

Thirty-five healthy older adults (female 25/male 10, mean age 73 ± 6 years) performed a graded exercise test on a cycle ergometer. VO2peak and VO2 recovery kinetics were assessed through gas exchange analysis. Muscle strength was determined by maximal leg (one-repetition maximum on leg press; 1RM) and grip strength, and physical performance was determined by the physical performance test (PPT) which assessed gait speed, stair ascent and descent, and timed up-and-go.

RESULTS

Higher VO2peak was associated with stronger leg (r = 0.59, p < 0.001) and grip strength (r = 0.39, p < 0.03), but no relationship to PPT (p > 0.05). There was also no relationship between VO2 recovery kinetics and leg and grip strength or PPT (p > 0.05).

CONCLUSION

In healthy community-dwelling older adults, VO2peak, but not VO2 recovery kinetics, is associated with muscle strength. This suggests that muscle strength may be an important factor related to aerobic capacity that could assist in identifying older adults who should be prioritized for resistance training.

Exercise training improves participation in persons with multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

Although previous studies have examined the effects of exercise training on other International Classification of Functioning, Disability and Health (ICF) component levels in persons with multiple sclerosis (MS), the effects of exercise training on participation remain unclear. The objectives of this review were to: (1) characterize systematically the use of outcome measures that capture participation in exercise training studies; (2) quantify the effect of exercise training on participation in persons with MS.

METHODS

A search of 6 electronic databases (CINAHL, SPORTDiscuss, Embase, MEDLINE, Cochrane Central, and Scopus) was conducted to identify controlled and noncontrolled trials involving exercise training and participation in persons with MS. Search strings were built from Medical Subject Headings and CINAHL headings. ICF linking rules were used to identify participation chapters and categories captured. Meta-analysis was used to quantify the effect of exercise training on participation in randomized controlled trials comparing exercise effects to no intervention/usual care.

RESULTS

We included 49 articles involving controlled and noncontrolled exercise trials in the systematic review of outcome measures. We captured 16 different outcome measures that captured all 9 participation chapters and identified 89 unique participation categories. Across these 16 outcome measures, mobility was the most commonly represented participation chapter, with 108 items. A subsample of 23 randomized controlled trials was included in the meta-analysis. An overall effect of 0.60 (standard error = 0.12, 95% confidence interval: 0.36-0.84, z = 4.9, p < 0.001) was calculated, indicating a moderate, positive effect of exercise training on participation.

CONCLUSION

The current review provides information that can be used to guide the selection of outcome measures that capture participation in studies of exercise training in persons with MS. Exercise training has a positive effect on outcomes that capture participation, providing further evidence for the role of exercise training in promoting and maintaining engagement in everyday life.

Aerobic reserve capacity in multiple sclerosis-Preliminary evidence

OBJECTIVES

Aerobic reserve capacity reflects the available energy for performing everyday life tasks, and it has been studied in older adult populations. This preliminary study examined proof of concept and measurement of aerobic reserve capacity in multiple sclerosis (MS).

MATERIALS & METHODS

Twenty-one fully ambulatory people with MS performed a maximal, cardiopulmonary exercise test (CPET). We calculated aerobic reserve capacity based on the difference between peak aerobic power (VO_2peak ) and first stage oxygen consumption (VO₂ ). Participants completed assessments for disability (Expanded Disability Status Scale, EDSS), cognition (Symbol Digit Modalities Test, SDMT), mood (Beck Depression Inventory, BDI), walking endurance (six-minute walk distance, 6MWD), walking speed (Timed Twenty-Foot Walk, T25FW), impact of MS (Multiple Sclerosis Impact Scale, MSIS-29), and anthropometric measurements (height and weight).

RESULTS

Aerobic reserve capacity was 9.3 ± 3.7 ml/kg/min. Aerobic reserve capacity was positively associated with VO_2peak (ρ = .67, p < .01), time to exhaustion (ρ = .63, p < .01), and SDMT (ρ = .51, p < .05). Aerobic reserve capacity was negatively associated with BMI (ρ = -.62, p < .01) and RHR (ρ = -0.47, p < .05).

CONCLUSION

We provide preliminary evidence that aerobic reserve capacity is a feasible outcome derived from maximal CPET (eg, modified Balke protocol) in MS. Aerobic reserve capacity was associated with clinically relevant outcomes and could become an important outcome for rehabilitation in future research.