Title: Physical activity and cardiorespiratory fitness after stroke
Other Titles: Fysieke activiteit en cardiorespiratoire fitheid na een cerebrovasculair accident
Authors: Baert, Ilse
Issue Date: 24-Apr-2012
Abstract: Physical activity (PA) and cardiorespiratory fitness (CRF) are reduced after stroke. To enhance participation in daily activities and structured exercise training, longitudinal evaluation of the level and influencing factors of PA and CRF after stroke is crucial. These insights help to identify barriers of PA and to better delineate aerobicexercise interventions and maintain long-term benefits. Studies carried out within this PhD-project included the prevalence and determinants of stroke caregivers# strain in the first six months after stroke (chapter 1), the criterion validity of heart rate monitoring versus RT3-accelerometry and examination of the accuracy of Yamax-pedometers instroke survivors (chapter 2), the quantity of PA one year after stroke and its influencing factors (chapter 3), the evolution of CRF during thefirst year post-stroke and the influence of pre-stroke patients# characteristics and stroke-related factors on this evolution(chapter 4),and the identification of determinants of CRF at 3, 6 and 12 months post-stroke (chapter 5).In chapter 1, the prevalence and determinants of strain experienced by 90 stroke patients# caregivers at 2, 4 and 6 months post-stroke were presented. Demographic characteristics, physical and emotional performance of patients, caregivers# characteristics and service input were documented to identify determinants of the caregivers# strain. Nearly one out of three caregivers was under strain and no differences were seen between 2, 4 and 6 months post-stroke. Our results also indicated that in predicting strain, the patients# level of function andactivity played an important role in the subacute phase while the participation level increased in importance over time. These findings emphasized the importance of maximal physical recovery and optimal integration in the community. Providing services in which patients can participate, such as social activities, leisure and sport related activities might help to reduce caregivers# strain and to prevent socialisolation of the patient.In the validation study (chapter 2) nine stroke patients performed a standardised activity protocol wearing a Cosmed K4b² to measure oxygen consumption and heart rate (HR), a RT3-accelerometer and two Yamax SW-200 pedometers (hip- and knee-positioned). We concluded that the RT3-accelerometer showed poor validity for measuring PA in stroke patients. HR monitoring, however, can be used to make intra-individual comparisons through providing patients with information on exercise i ntensity. This study further revealed that the Yamax SW-200 pedometer provided accurate results during slow walking if positioned on the knee,but not when hip-positioned. In conclusion, HR monitoring and knee-positioned Yamax-pedometers seemed to be useful instruments to assess PA in stroke survivors and could be seen as a motivational strategy to enhance PA.Chapter 3 addressed the question whether stroke patients are active enough 1-year post-stroke to improve their physical health. Due to the unique attribute of absolute, relative, and self-reported measures, PA was quantified by a multifaceted approach in 16 mildly disabled stroke patients. Our results showed that on average, stroke patients spent 44±39 minutes a day in activities of moderate intensity and performed 6428 steps per day which is within the normative data (5900-6900 steps/day). However, none performed moderate activity at least three days per week and only 19% performed more than 10,000 steps/day, required to improve/maintain their health. Functional mobility, CRF, mood and participation had an influence on daily steps, but not on the time spent in moderately intense activities. We could conclude that discrepancies between absolute (daily steps) and relative (minutes moderate active) measures of PA exist with respect to the quantity achieved and its potential determinants.In chapter 4 the evolution of CRF of 33 stroke patients in a 1-year follow-up study were examined and the effect of pre-stroke patients# characteristics and stroke-related factors on this evolution were explored. Findings revealed that on average CRF was reduced from 3 to 12months post-stroke (values were 65% to 71% of the age- and sex-matched normative values in healthy sedentary persons) and did not significantlychange over time. These results suggest that conventional stroke rehabilitation is insufficient to obtain a cardiorespiratory training effect. It seems worthwhile to initiate exercise-based interventions of sufficient intensity, frequency and duration in the rehabilitation centre and continuation in the community. Stroke survivors at risk of deconditioning were pre-morbid less active at work or in sport activities, diabetic or initially more severely impaired. Statistically combining these factors revealed that older patients with stroke and diabetes were less likely to improve their VO2 peak and older, female, diabetic non-smokers improved less on log OUES. These results indicate that cardiovascular exercise training could be a therapeutic goal for these patients at risk and preferably be started as early as possible. Pre-morbid less active persons require extra stimulation to change theirsedentary lifestyle and guidance post-rehabilitation will be essential to retain long-term benefits.In chapter 5, CRF was predicted based on standardized measures along theseveral dimensions of the ICF model at 3, 6 and 12 months post-stroke in40 patients with stroke. Knee muscle strength was found the main predictor of CRF and explained variance increased over time from 41% to 72%. Functional mobility and mood affected CRF at 12 months post-stroke.These results may suggest that cardiorespiratory endurance training should be supplemented with strength-developing exercises of the lower limbs, especially on the weaker paretic side. Ambulation at moderate intensity and good mental health may further positively influence CRF.
Publication status: published
KU Leuven publication type: TH
Appears in Collections:Research Group for Adapted Physical Activity and Psychomotor Rehabilitation
Policy in Sports & Physical Activity Research Group
Research Group for Neuromotor Rehabilitation

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