The effect of a structured running exercise intervention on non-exercise physical activity and sedentary behaviour in persons with mild Multiple Sclerosis and healthy controls

Abstract

Background: Exercise interventions fail to increase objective physical activity (PA) in persons with Multiple Sclerosis (PwMS), while they self-report higher exercise participation. This suggests that PwMS change their non-exercise PA (NEPA). We aimed to explore NEPA changes of PwMS and healthy controls (HC), and whether these constrain exercise adaptations.

Methods: Twenty-nine mildly-disabled PwMS and 26 HC completed a 10-month home-based running program. A non-randomised controlled study design was used. The primary outcome was time in different NEPA intensities (light intensity PA [LIPA] and moderate-to-vigorous intensity PA [MVPA]) and in sedentary behaviour ([SB]; total and uninterrupted SB) at baseline (T1), after 5 (T2) and 10 (T3) months of exercise. Data were averaged over days with and without exercise sessions (EX and NONEX days). Secondary outcomes included patient-reported and physical exercise adaptations (fatigue, walking mobility, blood pressure, body composition and cardiorespiratory fitness).

Results: A significant reduction in non-exercise MVPA was observed from T1 to T2 (- 113 ± 31 min/week, p < 0.01) and from T1 to T3 (- 95 ± 26 min/week, p < 0.01) in PwMS, which approximately matched the weekly exercise duration at those time points. PwMS also increased their uninterrupted SB on NONEX days compared to EX days (+ 0.7 ± 0.3 h, p < 0.01). There were no changes in MVPA or SB of HC (group × time effect MVPA: p < 0.05; group × EX day effect uninterrupted SB: p < 0.01). Secondary outcomes improved similarly in both groups and were not associated with NEPA/SB changes.

Conclusions: In contrast to HC, PwMS significantly changed their NEPA and the pattern in which they accumulated SB in response to structured exercise. This might be a necessary behavioural compensation in order to adhere to the exercise intervention and did not constrain patient-reported and physical outcomes. Future research is warranted to unravel the underlying causes and to investigate the effects on other exercise adaptations, such as cardiometabolic health. Trial registration The present study was registered (December 10, 2019) at clinicaltrials.gov as NCT04191772.

Keywords: Exercise; Exercise adaptations; Multiple Sclerosis; Non-exercise physical activity; Sedentary behaviour.

Fig. 1

Flow chart of study participants. CI Contra-indications, MVPA moderate-to-vigorous intensity physical activity, PwMS persons with Multiple Sclerosis, HC healthy controls, MSK musculoskeletal, PP per-protocol

Fig. 2

Non-exercise physical activity and sedentary behaviour. Solid lines present exercise days, dashed lines non-exercise days at T1 (before start of the intervention), T2 (5 months within the intervention), and T3 (last week of the intervention). PwMS are presented in red (red circle), HC in blue (blue square). A Moderate-to-vigorous intensity physical activity (MVPA), B light intensity physical activity (LIPA; stand + light intensity walking), and C sedentary behaviour (SB) are presented in % of waking time (WT) (without exercise time for EX days), D uninterrupted SB (time in sedentary bouts > 60 min) in hours (h)/day. All data are expressed as means ± SEM. An overview with the absolute data and exact p-values can be found in Additional file 3

Fig. 3

Time in hour per heart rate zone. Blue rectangular box 50–70%, Green rectangular box 70–80%, Red rectangular box 80–100% of HR_max. Percentages depicted in the bars present content adherence: % of total duration/time per heart rate zone according to the protocol (p > 0.05 between groups). MS Multiple Sclerosis, HC healthy controls. Data are expressed as means ± SEM