Ashlee Dunn

Characteristics of Exercise Training Interventions to Improve Cardiorespiratory Fitness After Stroke: A Systematic Review With Meta-analysis

Background. Cardiorespiratory fitness is low after stroke. Improving fitness has the potential to improve function and reduce secondary cardiovascular events. Objective. This review with meta-analysis aims to identify characteristics and determine the effectiveness of interventions to improve cardiorespiratory fitness after stroke. Methods. A systematic search and review with meta-analysis was undertaken. Key inclusion criteria were the following: peer-reviewed articles published in English, adult stroke survivors, an intervention with the potential to improve cardiorespiratory fitness, and peak oxygen consumption (VO2peak) assessed preintervention and postintervention via a progressive aerobic exercise test. Results. From 3209 citations identified, 28 studies were included, reporting results for 920 participants. Studies typically included chronic, ambulant participants with mild to moderate deficits; used an aerobic or mixed (with an aerobic component) intervention; and prescribed 3 sessions per week for 30 to 60 minutes per session at a given intensity. Baseline VO2peak values were low (8-23 mL/kg/min). Meta-analysis of the 12 randomized controlled trials demonstrated overall improvements in VO2peak of 2.27 (95% confidence interval = 1.58, 2.95) mL/kg/min postintervention. A similar 10% to 15% improvement occurred with both aerobic and mixed interventions and in shorter (≤3 months) and longer (>3 months) length programs. Only 1 study calculated total dose received and only 1 included long-term follow-up. Conclusions. The results demonstrate that interventions with an aerobic component can improve cardiorespiratory fitness poststroke. Further investigation is required to determine effectiveness in those with greater impairment and comorbidities, optimal timing and dose of intervention, whether improvements can be maintained in the longer term, and whether improved fitness results in better function and reduced risk of subsequent cardiovascular events.

Protocol variations and six-minute walk test performance in stroke survivors: a systematic review with meta-analysis.

Objective. To investigate the use of the six-minute walk test (6MWT) for stroke survivors, including adherence to 6MWT protocol guidelines and distances achieved. Methods. A systematic search was conducted from inception to March 2014. Included studies reported a baseline (intervention studies) or first instance (observational studies) measure for the 6MWT performed by stroke survivors regardless of time after stroke.  Results. Of 127 studies (participants n = 6,012) that met the inclusion criteria, 64 were also suitable for meta-analysis. Only 25 studies made reference to the American Thoracic Society (ATS) standards for the 6MWT, and 28 reported using the protocol standard 30 m walkway. Thirty-nine studies modified the protocol walkway, while 60 studies did not specify the walkway used. On average, stroke survivors walked 284 ± 107 m during the 6MWT, which is substantially less than healthy age-matched individuals. The meta-analysis identified that changes to the ATS protocol walkway are associated with reductions in walking distances achieved. Conclusion. The 6MWT is now widely used in stroke studies. The distances achieved by stroke patients indicate substantially compromised walking ability. Variations to the standard 30 m walkway for the 6MWT are common and caution should be used when comparing the values achieved from studies using different walkway lengths.

A Home- and Community-Based Physical Activity Program Can Improve the Cardiorespiratory Fitness and Walking Capacity of Stroke Survivors.

BACKGROUND The cardiorespiratory fitness of stroke survivors is low. Center-based exercise programs that include an aerobic component have been shown to improve poststroke cardiorespiratory fitness. This pilot study aims to determine the feasibility, safety, and preliminary efficacy of an individually tailored home- and community-based exercise program to improve cardiorespiratory fitness and walking capacity in stroke survivors. METHODS Independently ambulant, community-dwelling stroke survivors were recruited. The control (n = 10) and intervention (n = 10) groups both received usual care. In addition the intervention group undertook a 12-week, individually tailored, home- and community-based exercise program, including once-weekly telephone or e-mail support. Assessments were conducted at baseline and at 12 weeks. Feasibility was determined by retention and program participation, and safety by adverse events. Efficacy measures included change in cardiorespiratory fitness (peak oxygen consumption [VO2peak]) and distance walked during the Six-Minute Walk Test (6MWT). Analysis of covariance was used for data analysis. RESULTS All participants completed the study with no adverse events. All intervention participants reported undertaking their prescribed program. VO2peak improved more in the intervention group (1.17 ± .29 L/min to 1.35 ± .33 L/min) than the control group (1.24 ± .23 L/min to 1.24 ± .33 L/min, between-group difference = .18 L/min, 95% confidence interval [CI]: .01-.36). Distance walked improved more in the intervention group (427 ± 123 m to 494 ± 67m) compared to the control group (456 ± 101m to 470 ± 106m, between-group difference = 45 m, 95% CI: .3-90). CONCLUSIONS Our individually tailored approach with once-weekly telephone or e-mail support was feasible and effective in selected stroke survivors. The 16% greater improvement in VO2peak during the 6MWT achieved in the intervention versus control group is comparable to improvements attained in supervised, center-based programs.

Independently ambulant, community–dwelling stroke survivors have reduced cardiorespiratory fitness, mobility and knee strength compared to an age- and gender-matched cohort

Background: Most exercise interventions for stroke survivors are designed for those who have substantial motor and functional disabilities. There remains a group of well-recovered stroke survivors who have yet to be investigated in terms of their physical capacity and fitness levels. Objective: To assess and compare the physical capacities of independently ambulant, community-dwelling stroke survivors to age- and gender-matched comparison participants. Methods: Data were obtained from 17 stroke survivors participating in the How FITSS? Trial, all with functional ambulatory category of ≥4 and a self-selected walking speed ≥0.8 m s−1. An additional 17 healthy control participants were recruited. Cardiorespiratory fitness (CRF) was measured using oxygen consumption (VO2peak), and additional measures of walking speed (m s−1), leg strength and body composition were also assessed. Differences between groups were assessed by matched pairs t-tests. Effect sizes were calculated using Cohen’s d. Results: There were no significant differences in age, BMI, muscle mass or body fat between groups (p > 0.05). Peak VO2 was lower in the stroke group for the shuttle walk test (p = 0.037) and progressive cycle test (p = 0.019), as were all CRF test performance measures (p < 0.05). Stroke survivors walked significantly (p < 0.001) slower at both self-selected and fast speeds. Effect sizes of group differences for all leg strength variables were medium to large, with peak torque lower in the stroke group for all trials. Conclusions: Despite being independently ambulant and community dwelling, the CRF, walking speed and leg strength of this group were reduced compared to non-stroke comparison participants. These patients may benefit from undertaking targeted exercise programmes.

Breaking up sitting time after stroke (BUST-Stroke).

Rationale Prolonged sitting is associated with an increased risk of cardiovascular and all-cause mortality and morbidity. The metabolic and cardiovascular effects of breaking up sitting time in people with stroke are unknown. Aims and hypotheses To determine the (i) metabolic and cardiovascular effects and (ii) safety and feasibility of an experimental protocol to break up uninterrupted sitting in people with stroke. We hypothesize that activity breaks will attenuate the effects of uninterrupted sitting on glucose and insulin metabolism, blood pressure, lipid profiles, and plasma fibrinogen and that it will be both safe and feasible. Sample size estimate Based on previous estimates of population variability (SD 1% glucose and 30% insulin), 19 paired observations (i.e. participants) will achieve a power of 0.9 to detect a difference of 0.8% in glucose and 24% in insulin area under the curve (two-tailed testing, α = 0.05). Methods and design People with stroke will complete three experimental conditions one week apart in randomized order: (a) uninterrupted sitting, (b) prolonged sitting with intermittent walking, and (c) prolonged sitting with intermittent standing exercises. Serial blood samples will be collected and blood pressure measured at 30 min intervals for 8 h. Study outcomes Primary outcome will be postprandial glucose and insulin responses. Secondary outcomes will include fibrinogen concentrations, blood pressure, and adverse events and protocol feasibility. Discussion This is the first important step in determining the cardiovascular effects of breaking up sitting time after stroke. Findings will guide future studies testing behavioral strategies to reduce sitting time for the purpose of lowering recurrent stroke risk.

Exercise capacity is not decreased in children who have undergone lung resection early in life for congenital thoracic malformations compared to healthy age-matched children

The purpose of this study was to compare (i) the exercise capacity and (ii) lung function prior to and immediately post cardiopulmonary exercise tests (CPET) of children who underwent early life lung resection for Congenital Pulmonary Airway Malformations (CPAM) to healthy control children.

Cardiorespiratory fitness and walking endurance improvements after 12 months of an individualised home and community-based exercise programme for people after stroke

ABSTRACT Objective: To evaluate the immediate and longer-term effects of an individually tailored, home- and community-based exercise programme with ongoing remote support in people with stroke on cardiorespiratory fitness (CRF), ambulation and health-related quality of life (HRQoL). Methods: Twenty people 5.3 ± 3.5 months post stroke completed the 12-week HowFITSS? exercise programme aimed at increasing CRF and daily physical activity. Support was provided by phone and email, which decreased in frequency over time. Participants were assessed at baseline, then at 3, 6 and 12 months after initiation of the intervention. CRF (VO2peak) was evaluated using a portable metabolic system during the 6-minute walk test (6MWT), the Shuttle Walk Test (SWT) and the cycle graded exercise test (cGXT). Walking speed, balance, body composition, fatigue, depression and HRQoL were also measured. Results: CRF improved significantly from pre-intervention to 12-month follow-up on the 6MWT (Effect Size, ES = 0.87; p = 0.002) and cGXT (ES = 0.60; p < 0.001), with more modest improvements on the SWT (ES = 0.52; p = 0.251). From baseline to 12 months, significant within-participant improvements were found for self-selected walking speed, balance and HRQoL. Performances on the remaining tests were maintained over the post-intervention period. Conclusion: There may be health benefits of providing people with stroke an exercise intervention with long-term support that encourages increased regular physical activity.

Evaluation of three measures of cardiorespiratory fitness in independently ambulant stroke survivors

ABSTRACT Measuring cardiorespiratory fitness (CRF) in the stroke population is challenging. Currently, the recommended method is a graded exercise test (GXT) on an ergometer such as a treadmill or cycle, which may not always be possible. We investigated whether walking tests such as the six-minute walk test (6MWT) and the shuttle walk test (SWT) may be appropriate indicators of CRF in the stroke population. Twenty-three independently ambulant stroke survivors (11 men, age 61.5 ± 18.4 years) within one-year post stroke performed the 6MWT, SWT, and cycle GXT, during which peak oxygen consumption (VO2peak) and heart rate (HRpeak) were recorded. There were no differences (p > 0.05) in mean VO2peak among the three tests (min-max: 17.08–18.09 mL kg−1 min−1). For individuals, small discrepancies in VO2peak between the 6MWT and other tests were greater with higher fitness levels. HRpeak was significantly (p = 0.005) lower during the 6MWT. Correlations between VO2peak and performance measures within each test were high (6MWT VO2peak and distance: r = 0.78, SWT VO2peak and shuttles: r = 0.73, cycle GXT VO2peak and workload: r = 0.77) suggesting the performance measures may be clinically useful as proxy measures of CRF. Common comorbidities, such as lower-limb joint pain and poor balance, and participant’s fastest walking speed, should inform the choice of CRF test.

Frequent, short bouts of light-intensity exercises while standing decreases systolic blood pressure: Breaking Up Sitting Time after Stroke (BUST-Stroke) trial:

Background Stroke survivors sit for long periods each day. Uninterrupted sitting is associated with increased risk of cardiovascular disease. Breaking up uninterrupted sitting with frequent, short bouts of light-intensity physical activity has an immediate positive effect on blood pressure and plasma clotting factors in healthy, overweight, and type 2 diabetic populations. Aim We examined the effect of frequent, short bouts of light-intensity physical activity on blood pressure and plasma fibrinogen in stroke survivors. Methods Prespecified secondary analyses from a three-armed randomized, within-participant, crossover trial. Participants were 19 stroke survivors (nine female, aged 68 years old, 90% able to walk independently). The experimental conditions were sitting for 8 h uninterrupted, sitting with 3 min bouts of light-intensity exercise while standing every 30 min, or sitting with 3 min of walking every 30 min. Blood pressure was measured every 30 min over 8 h and plasma fibrinogen at the beginning, middle, and end of each day. Intention-to-treat analyses were performed using linear mixed models including fixed effects for condition, period, and order, and a random intercept for participant to account for repeated measures and missing data. Results Sitting with 3 min bouts of light-intensity exercise while standing every 30 min decreased systolic blood pressure by 3.5 mmHg (95% CI 1.7–5.4) compared with sitting for 8 h uninterrupted. For participants not taking antihypertensive medications, sitting with 3 min of walking every 30 min decreased systolic blood pressure by 5.0 mmHg (95% CI −7.9 to 2.0) and sitting with 3 min bouts light-intensity exercise while standing every 30 min decreased systolic blood pressure by 4.2 mmHg (95% CI −7.2 to −1.3) compared with sitting for 8 h uninterrupted. There was no effect of condition on diastolic blood pressure (p = 0.45) or plasma fibrinogen levels (p = 0.91). Conclusion Frequent, short bouts of light-intensity physical activity decreases systolic blood pressure in stroke survivors. However, before translation into clinical practice, the optimal duration and timing of physical activity bouts needs to be determined. Clinical trial registration Australian and New Zealand Clinical Trials Registry http://www.anzctr.org.au ANZTR12615001189516.

AExaCTT - Aerobic Exercise and Consecutive Task-specific Training for the upper limb after stroke: protocol for a randomised controlled pilot study

Motor function may be enhanced if aerobic exercise is paired with motor training. One potential mechanism is that aerobic exercise increases levels of brain-derived neurotrophic factor (BDNF), which is important in neuroplasticity and involved in motor learning and motor memory consolidation. This study will examine the feasibility of a parallel-group assessor-blinded randomised controlled trial investigating whether task-specific training preceded by aerobic exercise improves upper limb function more than task-specific training alone, and determine the effect size of changes in primary outcome measures. People with upper limb motor dysfunction after stroke will be allocated to either task-specific training or aerobic exercise and consecutive task-specific training. Both groups will perform 60 hours of task-specific training over 10 weeks, comprised of 3 × 1 hour sessions per week with a therapist and 3 × 1 hours of home-based self-practice per week. The combined intervention group will also perform 30 minutes of aerobic exercise (70–85%HRmax) immediately prior to the 1 hour of task-specific training with the therapist. Recruitment, adherence, retention, participant acceptability, and adverse events will be recorded. Clinical outcome measures will be performed pre-randomisation at baseline, at completion of the training program, and at 1 and 6 months follow-up. Primary clinical outcome measures will be the Action Research Arm Test (ARAT) and the Wolf Motor Function Test (WMFT). If aerobic exercise prior to task-specific training is acceptable, and a future phase 3 randomised controlled trial seems feasible, it should be pursued to determine the efficacy of this combined intervention for people after stroke.