- Title
- An exploration of low doses of exercise on cardiorespiratory fitness in people with chronic stroke
- Creator
- Galloway, Margaret
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2019
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Background: Low levels of cardiorespiratory fitness and physical activity are common after stroke, and can increase the risk of secondary stroke. Exercise training can increase cardiorespiratory fitness after stroke, however the minimal or optimal exercise dose to increase cardiorespiratory fitness is unclear. People with chronic stroke do not achieve the levels of physical activity recommended in current physical activity guidelines, and it is possible lower doses of exercise may be effective in increasing cardiorespiratory fitness. Objective: The primary aim of this thesis was to explore the effect of low doses of aerobic exercise on cardiorespiratory fitness and physical activity levels after stroke to determine if a minimum dose of exercise is required to improve cardiorespiratory fitness. The secondary aim was to assess the feasibility of delivering low-dose aerobic exercise to people after stroke via telehealth. Methods: To address these objectives I undertook four studies: Study 1: I conducted a systematic review to synthesise the current evidence for the effects of different doses of exercise on cardiorespiratory fitness and walking capacity in people after stroke. Study 2: I conducted a Phase I dose-escalation trial of low doses of aerobic exercise to determine the i) tolerability, preliminary efficacy and dose-response of low doses of aerobic exercise, and ii) effect of low-dose exercise on cardiorespiratory fitness, walking ability and quality of life on community-dwelling ambulant chronic stroke survivors. Four doses of exercise were assessed. 20 participants in consecutive cohorts (n=5 per cohort) received home-based telehealth-supervised aerobic exercise. The intervention frequency, program length and intensity were kept constant (3 d/week, 8-weeks, and moderate-vigorous [55-85% HRpeak]) and the doses varied by session duration (Dose 1 = 10 min, Dose 2 = 15 min, Dose 3 = 20 min, Dose 4 = 25 min) We set a priori rules to determine dose-limiting thresholds and dose efficacy to guide the conduct of the dose-escalation trial. Doses were escalated if < 33% of a cohort reached a dose-limiting threshold. Doses were efficacious if ≥ 67% of a cohort increased peak oxygen consumption (VO2peak) ≥ 2mL/kg/min. Study 3: I undertook a secondary analysis of data collected in Study 2 to determine i) the effect the exercise intervention on physical activity levels and sedentary behaviour in people with chronic stroke during and after the exercise intervention, and ii) the relationship between changes in physical activity and changes in cardiorespiratory fitness. Study 4: Participants in the exercise intervention in Study 2 were supervised by telehealth. The feasibility of, and level of satisfaction with home-based telehealth-supervised aerobic exercise training for people after stroke were assessed using participant feedback and data collected during exercise sessions by the exercise instructor. Results: Study 1. The review included 9 trials (n = 279 participants). Training at higher exercise intensities was associated with greater improvements in cardiorespiratory fitness (VO2peak). Walking capacity increased with longer program length in most studies, however the effect of exercise intensity on walking capacity (6-min walk test) was unclear. No trials compared doses of different exercise training frequencies, different exercise session durations, or different types or modes of exercise training. Study 2: Exercise doses ranging from 10 min up to 25 min/session were tolerable for all participants (no participants reached the dose-limiting threshold). Preliminary efficacy was not established for any doses. The mean improvement in cardiorespiratory fitness for the 20 min/session dose was 3.0 mL/kg/min, 95% CI 0.6 to 5.4, and this dose merits further investigation. In pooled data from all dose cohorts low-dose (short duration) exercise resulted in increased cardiorespiratory fitness (ΔVO2peak = 1.9 mL/kg/min, 95% CI 0.7 to 3.2, walking capacity (Δ6-minute walk test = 25m, 95% CI 8 to 40) and self-rated health status (ΔEQ-VAS score = 9, 95% CI 3 to 15). Study 3: 8 weeks of home-based supervised aerobic training had no effect overall on the level of habitual physical activity. Physical activity (steps/day) was 33% higher (mean difference 1675 steps/day; 95% CI: 840 to 2510) on training days compared to non-training days, and changes in physical activity (steps/day) were moderately associated with changes in cardiorespiratory fitness (VO2peak) (r=0.44, p=0.05). Study 4: Outcome feasibility measures for the telehealth-supervised exercise intervention were high from the perspective of both participants and researchers. Neither age, level of post-stroke impairment nor level of technical familiarity were associated with participants’ level of satisfaction, and for eligible participants who enrolled, were not barriers to successfully participating in telehealth supervised exercise sessions. Conclusion: Low doses of home-based telehealth-supervised aerobic exercise for community-dwelling chronic stroke survivors were tolerable. Participants exercised at a moderate-vigorous intensity, 3 times per week for 8 weeks, and engaged safely and successfully in telehealth-supervised exercise sessions. The findings will be used to inform the development of an intervention for a Phase II trial of supervised exercise delivered via telehealth to reduce secondary stroke risk.
- Subject
- stroke; cardiorespiratory fitness; telehealth; telemedicine; exercise; aerobic exercise; physical activity
- Identifier
- http://hdl.handle.net/1959.13/1407802
- Identifier
- uon:35782
- Rights
- Copyright 2019 Margaret Galloway
- Language
- eng
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 10 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 741 KB | Adobe Acrobat PDF | View Details Download |