Cardiorespiratory fitness training early after stroke
AuthorKramer, Sharon Flora
AffiliationFlorey Department of Neuroscience and Mental Health
Document TypePhD thesis
Access StatusOpen Access
© 2018 Dr. Sharon Flora Kramer
Cardiorespiratory fitness (CRF) levels are low in stroke survivors. Although there is strong evidence that physical fitness training improves CRF in stroke survivors, there is a lack of knowledge about the safety and tolerability of CRF training for stroke survivors in the acute phase (i.e., <1 month post-stroke). The aim of this thesis was to systematically develop a CRF training intervention and to design a novel dose escalation trial to determine the maximum safe and tolerable dose intensity of the CRF intervention. High energy demands (i.e., oxygen uptake) during physical activity after stroke could prevent stroke survivors from performing CRF training. A systematic review was conducted and found that the energy demands during walking in stroke survivors are higher than healthy controls. However, no studies were identified in which stroke survivors in the acute phase were included. In a clinical observational study the ability of stroke survivors in the acute phase to perform physical activity under steady state conditions (i.e., the oxygen supply meets the oxygen demands of muscle tissue), and the difference in energy demands during steady state activity compared to healthy controls was determined. Reaching a steady state allows sustained physical activity required for CRF training. All stroke survivors reached a steady state within six minutes of activity, and energy demands of steady state activity were higher than controls. The results indicate that stroke survivors potentially are able to perform a CRF training session (i.e., >20 minutes). Another aim was to determine the validity of a small wearable device, to measure energy demands during activity against a gold standard. If proven valid it would be included in the final study of this thesis to monitor exercise intensity during training sessions. The device did not accurately measure energy demands of activity and was not included in the final trial. A comprehensive review of the literature of randomised controlled trials of physical fitness interventions for stroke survivors was conducted. The review focussed on the development of the interventions, the dose parameters and progression, and safety of the intervention. The development of physical fitness interventions seems to lack a systematic approach. The choice of dose-parameters was pragmatic rather than evidence-based. Progression and safety of the interventions were poorly reported. Informed by the findings of the review, a CRF training intervention was developed and a novel adapted dose escalation trial was developed to determine the maximum safe and tolerable dose of the CRF training intervention for stroke survivors in the acute phase. The trial commenced in June 2016 but has not been completed yet, due to the time restrictions of the PhD candidature. The preliminary results showed that all fifteen participants included so far were able to complete the CRF training without dose limiting events. This thesis found that an adapted dose escalation trial can be a valuable tool in the systematic development of exercise intervention. The preliminary data showed that mildly affected stroke survivors in the acute phase are able to safely perform CRF training at an intensity level that can potentially lead to a CRF training effect.
Keywordsacute stroke; exercise capacity; dose; dose escalation; trial design; cardiorespiratory fitness
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