Hemodynamic variability and cerebrovascular control after transient cerebral ischemia.

We investigated if hemodynamic variability, cerebral blood flow (CBF) regulation, and their interrelationships differ between patients with transient ischemic attack (TIA) and controls. We recorded blood pressure (BP) and bilateral middle cerebral artery flow velocity (MCAv) in a cohort of TIA patients (n = 17), and age-matched controls (n = 15). Spontaneous fluctuations in BP and MCAv were characterized by spectral power analysis, and CBF regulation was assessed by wavelet phase synchronization analysis in the very low- (0.02-0.07 Hz), low- (0.07-0.20 Hz), and high-frequency (0.20-0.40 Hz) ranges. Furthermore, cerebrovascular CO2 reactivity was assessed as a second metric of CBF regulation by inducing hypercapnia with 8% CO2 inhalation followed by hyperventilation driven hypocapnia. We found that TIA was associated with higher BP power (group effect, P < 0.05), but not MCAv power (P = 0.11). CBF regulation (assessed by wavelet phase synchronization and CO2 reactivity) was intact in patients (all P ≥ 0.075) across both hemispheres (all P ≥ 0.51). Pooled data (controls and affected hemisphere of patients) showed that BP and MCAv power were positively correlated at all frequency ranges (R(2) = 0.20-0.80, all P < 0.01). Furthermore, LF phase synchronization index was a significant determinant of MCAv power (P < 0.05), while VLF and HF phase synchronization index, and TIA were not (all P ≥ 0.50). These results indicate that CBF stability and control is maintained in TIA patients, but BPV is markedly elevated. BPV attenuation may be an important therapeutic strategy for enhancing secondary stroke prevention in patients who suffer a TIA.

The efficacy of a self-paced VO2max test during motorized treadmill exercise.

PURPOSE: To assess the utility of a self-paced maximal oxygen uptake (VO2max) test (SPV) in eliciting an accurate measure of VO2max in comparison with a traditional graded exercise test (GXT) during motorized treadmill exercise. DESIGN: This was a cross-sectional experimental study whereby recreationally trained men (n = 13, 25.5 ± 4.6 y) completed 2 maximal exercise tests (SPV, GXT) separated by a 72-h recovery period. METHODS: The GXT was continuous and incremental, with prescribed 1-km/h increases every 2 min until the attainment of VO2max. The SPV consisted of 5 × 2-min stages of incremental exercise, which were self-selected and adjusted according to 5 prescribed RPE levels (RPE 11, 13, 15, 17, and 20). RESULTS: Although no significant differences in VO2max were observed between the SPV and GXT (63.9 ± 3.3 cf 60.9 ± 4.6 mL · kg-1 · min-1, respectively, P > .05), the apparent 4.7% mean difference may be practically important. The 95% limits-of-agreement analysis was 3.03 ± 11.49 mL · kg-1 · min-1. Therefore, in the worst-case scenario, the GXT may underestimate measured VO2max as ascertained by the SPV by up to 19%. Conversely, the SPV could underestimate the GXT by 14%. CONCLUSIONS: The current study has shown that the SPV is an accurate measure of VO2max during exercise on a motorized treadmill and may provide a slightly higher VO2max value than that obtained from a traditional GXT. The higher VO2max during the SPV may be important when prescribing training or monitoring athlete progression.

A randomized controlled trial to assess the psychosocial effects of early exercise engagement in patients diagnosed with transient ischaemic attack and mild, non-disabling stroke.

OBJECTIVE: To examine the effect of an early exercise and education programme on psychosocial health of transient ischaemic attack (TIA) and mild, non-disabling stroke patients. DESIGN: Randomized, parallel-group, clinical trial. SETTING: Hospital and academic institution. PARTICIPANTS: A total of 55 newly diagnosed transient ischaemic attack/mild stroke patients (Mean[SD]; 69[11]y). INTERVENTION: Participants were randomized to either an eight-week, twice weekly, 90-minute exercise and education programme (experimental group) or to a usual care control group. MAIN MEASURES: Psychosocial measures (SF-36, Hospital Anxiety and Depression Scale, Profile of Mood States, International Physical Activity Questionnaire, Stroke Awareness Questionnaire) were assessed at baseline and eight-week and 12-month follow-up. RESULTS: The experimental group demonstrated improvements in the Physical Component Score (Mean[SD]; 44.1[11.7] to 47.4[11.3]%), Vitality (46.5[12.4] to 54.2[14.2]%), Physical Functioning (45.6[10.7] to 51.9[14.7]%), Role Physical (38.7[10.8] to 43.1[13.6]%) and Global Health (49.1[10.3] to 54.4[13.6]%) from the SF-36, at the eight-week follow-up assessment (P < 0.05). There were no further changes in these measures between the eight-week and 12-month follow-up assessment (P > 0.05). The experimental group demonstrated a greater awareness of the signs and symptoms associated with stroke (P < 0.05). There were no differences in the Mental Component Score (SF-36), the Hospital Anxiety and Depression Scale or the International Physical Activity Questionnaire between treatment groups (P > 0.05). CONCLUSION: Early engagement in an exercise and education programme may improve physical health perceptions in transient ischaemic attack/mild stroke patients. However, secondary prevention exercise and education programmes warrant further research with regards to their effects on perceptions of mental health in this population group.

The long-term effect of exercise on vascular risk factors and aerobic fitness in those with transient ischaemic attack: a randomized controlled trial.

OBJECTIVE: Exercise has beneficial effects on vascular risk factors in transient ischaemic attack (TIA) patients within the sub-acute phase. This study examined whether TIA patients randomized to an early exercise and education programme within 2 weeks of TIA diagnosis would demonstrate improvements in cardiovascular risk factors and aerobic fitness 12 months post-diagnosis compared with control patients. METHODS: A single-centre, randomized, parallel-group clinical trial. Sixty TIA patients (69 ±â€Š11 years) completed a vascular risk stratification baseline assessment and a physical fitness examination. Individuals were randomized to either an 8-week early exercise and education group or control group. Fifty-one patients attended post-intervention assessments that were completed immediately (post-intervention) and 12 months after (12PI). RESULTS: A significantly greater improvement in resting SBP was observed between baseline and post-intervention for EX than for CON (-11 mmHg cf. -1 mmHg, respectively; P < 0.05). The improvement in SBP was maintained between post-intervention and 12PI (P > 0.05). Similar findings were demonstrated for BMI, bodyweight and peak oxygen uptake (P < 0.05). Exercise blood pressure, pulse pressure and double product (SBP x heart rate; an indication of myocardial workload) were significantly lower at post-intervention and 12PI for EX than for CON (all P < 0.05). CONCLUSION: An 8-week exercise programme soon after TIA resulted in beneficial changes in resting and exercise blood pressure that were maintained for 12 months. CLINICAL TRIAL REGISTRATION: http://www.anzctr.org.au/ TRIAL REGISTRATION NUMBER: ACTRN12611000630910.

Effects of early exercise engagement on vascular risk in patients with transient ischemic attack and nondisabling stroke.

The objective of this study was to conduct a randomized, parallel-group clinical trial assessed the efficacy of a health-enhancing physical activity program (exercise and education) on vascular risk factors and aerobic fitness in patients who have experienced a transient ischemic attack (TIA) or nondisabling stroke. Sixty patients (69±11 years) completed a baseline (BL) vascular risk stratification and aerobic fitness examination (cycle test) within 2 weeks of symptom onset. Subjects were then randomized to either an 8-week, twice weekly exercise program or to a usual-care control (CON) group. Postintervention (PI) assessments were completed immediately after the intervention and at 3-month follow-up. A series of primary (systolic blood pressure [SBP]) and secondary (vascular risk factors like total cholesterol [TC], high-density lipoproteins, etc.; Framingham risk score; peak oxygen uptake) outcome measures were assessed. Significantly greater reductions in SBP (mean change±SD; -10.4±9.2 mm Hg) and TC (-.53±.90 mmol/L) were observed between BL and PI assessments for the exercise group compared with the CON group (-1.9±15.4 mm Hg and -.08±.59 mmol/L, respectively) (P<.05). These improvements were maintained between the PI and the 3-month follow-up assessment (P>.05). Significant improvements in aerobic fitness were also observed and maintained at the 3-month follow-up assessment after regular exercise participation (P<.05). The early engagement in exercise resulted in significant improvements in vascular risk factors and fitness in those diagnosed with TIA. As these beneficial effects were maintained up to 3 months after completing the exercise program, exercise should be considered a useful additive treatment strategy for newly diagnosed TIA patients. Future research should examine the long-term efficacy of such programs.

Health-enhancing physical activity programme (HEPAP) for transient ischaemic attack and non-disabling stroke: recruitment and compliance.

AIM: To assess the feasibility of recruiting and retaining patients newly diagnosed with a Transient Ischaemic Attack (TIA) into an 8-week exercise programme. METHODS: The study was a single-centre, randomised-controlled trial. TIA was confirmed by a specialist stroke physician within 7 days of symptom onset. Following baseline assessment, participants were randomised to either an 8-week exercise intervention or control group (usual care). Participants completed a further assessment 2 months after baseline. RESULTS: Of the 285 individuals diagnosed with TIA, 97 patients were invited to participate in the trial, of which 60 were successfully recruited (62%). Of those invited, 89% were identified within outpatient care. Individuals were typically of European descent (87%) and lived within 20 km of the study site (81%). Distance to travel was considered the primary barrier for non-participation (46%). Three participants (5%) did not attend the follow-up assessment. CONCLUSION: Individuals with TIA were successfully recruited and retained into a RCT. A different approach is required to study interventions in Maori, Pacific Islanders, Asian and Indian populations. If the exercise intervention improves vascular risk factors and reduces recurrent vascular events, it could be applied to a large number of people who suffer a TIA or non-disabling stroke.

The effect of estimation and production procedures on running economy in recreational athletes.

OBJECTIVES: Running economy is an important component in any endurance event. However, the influence of effort perception on running economy has yet to be examined. DESIGN: The purpose of this study was to assess the oxygen cost of running (running economy) at identical ratings of perceived exertion (RPE) during estimation (EST) and production (PR) procedures, during treadmill exercise. METHODS: Fourteen, well-trained male participants actively produced (self-regulated) a range of submaximal exercise intensities equating to RPE values 9, 11, 13, 15 and 17, and passively estimated their perception of exertion during an incremental graded-exercise test (GXT). Allometric scaling was used to ensure an appropriate comparison in running economy between conditions. RESULTS: The present study demonstrated that the overall running economy between conditions was statistically similar (p>0.05). A significant interaction was however identified between Conditions and RPE (p<0.001). The interaction revealed that running economy significantly improved during PR but remained fairly consistent during EST between moderate and high perceptions of exertion (RPE 11-17). Despite similarities in running economy between conditions, physiological (oxygen uptake, heart rate, minute ventilation and blood lactate) and physical (running velocity) markers of exercise intensity were significantly higher during EST for equivalent perceptions of exertion (all p<0.05). CONCLUSIONS: Passive estimation procedures may improve running economy and enhance athletic performance when compared to identical perceptions of exertion elicited during active production procedures. Athletes, coaches and physical trainers should consider the perceptual procedures utilised during training to ensure that an athlete trains at the most effective training intensity.