Michael A. Rippee

Aerobic Exercise in Subacute Stroke Improves Cardiovascular Health and Physical Performance

Background and Purpose: Cardiovascular health is often impaired after stroke. Reduced exercise capacity ( O2peak) and changes in the vascular system in the stroke-affected limb may impact performance of physical activities such as walking. There is little information regarding the role of prescribed moderate- to high-intensity exercise in subacute stroke. The purpose of this study was to examine whether an 8-week aerobic exercise intervention would improve cardiovascular health and physical performance in participants with subacute stroke. Methods: Ten subjects were enrolled in the study and 9 of them completed the intervention. Participants were aged 61.2 ± 4.7 years old, were 66.7 ± 41.5 days poststroke, and had minor motor performance deficits (Fugl-Meyer score, 100.3 ± 29.3). Outcome measures were taken at baseline, postintervention, and at 1-month follow-up. Brachial artery vasomotor reactivity (flow-mediated dilation [FMD]) of both arms was used to assess vascular health, and a peak exercise test was used to assess exercise capacity. The 6-minute walk test (6MWT) was used to assess physical performance. Participants exercised on a recumbent stepper 3 times per week for 8 weeks at a prescribed heart rate intensity. Results: At baseline, we identified between-limb differences in brachial artery FMD and low O2peak values. After the intervention, significant improvements were observed in the FMD in both arms, resting systolic blood pressure, and the 6MWT. Although we also observed improvements in the resting diastolic blood pressure, heart rate, and O2peak values, these changes were not significantly different. Discussion and Conclusion: Aerobic exercise in participants with subacute stroke was beneficial for improving cardiovascular health, reducing cardiac risk, and improving physical performance (6MWT). Video abstract available (see the Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A29) for more insights from the authors.

Use of Accelerometers to Examine Sedentary Time on an Acute Stroke Unit

Background and Purpose: Observational studies demonstrate low levels of physical activity during inpatient stroke rehabilitation. There are no prior studies that have objectively measured sedentary time on the acute stroke unit and whether sedentary time is related to functional outcomes. The purpose of this study was to characterize sedentary time after acute stroke and determine whether there is a relationship to functional performance at discharge. Methods: Thirty-two individuals (18 men; 56.5 ± 12.7 years) with acute stroke were enrolled within 48 hours of hospital admission. An accelerometer was placed on the stroke-affected ankle to measure 24-hour activity and was worn for 4 days or until discharge from the hospital. Performance of activities of daily living, walking endurance, and functional mobility were assessed using the Physical Performance Test, Six-Minute Walk Test, and Timed Up and Go, respectively. Results: Mean percent time spent sedentary was 93.9 ± 4.1% and percent time in light activity was 5.1 ± 2.4%. When controlling for baseline performance, the mean time spent sedentary per day was significantly related to Physical Performance Test performance at discharge (r = −0.37; P = .05), but not the Six-Minute Walk Test or Timed Up and Go. Discussion and Conclusions: Patients with acute stroke were sedentary most of their hospital stay. To minimize the potential negative effects of inactivity, our data suggest that there should be greater emphasis on increasing physical activity during the hospital stay. Video Abstract Available for more insights from the authors (Supplemental Digital Content 1, http://links.lww.com/JNPT/A101).

Estimated Prestroke Peak VO2 Is Related to Circulating IGF-1 Levels During Acute Stroke

Background. Insulin-like growth factor-1 (IGF-1) is neuroprotective after stroke and is regulated by insulin-like binding protein-3 (IGFBP-3). In healthy individuals, exercise and improved aerobic fitness (peak oxygen uptake; peak VO2) increases IGF-1 in circulation. Understanding the relationship between estimated prestroke aerobic fitness and IGF-1 and IGFBP-3 after stroke may provide insight into the benefits of exercise and aerobic fitness on stroke recovery. Objective. The purpose of this study was to determine the relationship of IGF-1 and IGFBP-3 to estimated prestroke peak VO2 in individuals with acute stroke. We hypothesized that (1) estimated prestroke peak VO2 would be related to IGF-1 and IGFBP-3 and (2) individuals with higher than median IGF-1 levels will have higher estimated prestroke peak VO2 compared to those with lower than median levels. Methods. Fifteen individuals with acute stroke had blood sampled within 72 hours of hospital admission. Prestroke peak VO2 was estimated using a nonexercise prediction equation. IGF-1 and IGFBP-3 levels were quantified using enzyme-linked immunoassay. Results. Estimated prestroke peak VO2 was significantly related to circulating IGF-1 levels (r = .60; P = .02) but not IGFBP-3. Individuals with higher than median IGF-1 (117.9 ng/mL) had significantly better estimated aerobic fitness (32.4 ± 6.9 mL kg−1 min−1) than those with lower than median IGF-1 (20.7 ± 7.8 mL kg−1 min−1; P = .03). Conclusions. Improving aerobic fitness prior to stroke may be beneficial by increasing baseline IGF-1 levels. These results set the groundwork for future clinical trials to determine whether high IGF-1 and aerobic fitness are beneficial to stroke recovery by providing neuroprotection and improving function.

Decreased tidal volume may limit cardiopulmonary performance during exercise in subacute stroke.

PURPOSE: The aim of this retrospective study was to determine whether pulmonary function was reduced at submaximal and peak exercise in subacute stroke (SG) when compared with sedentary adults (CON). METHODS: Ten individuals with subacute stroke and 10 sedentary, age- and gender-matched adults performed cardiopulmonary exercise testing (CPET), using a recumbent stepper. We used independent t tests to determine between-group differences at peak effort. We used repeated-measures analysis of variance with Test Minute (minutes 1-6) as the within-subject factor and Group (SG, CON) as the between-subject factor to assess cardiopulmonary submaximal performance. RESULTS: The SG had significantly lower values (P < .05) for oxygen uptake, minute ventilation ( E), and tidal volume (VT) than CON at peak effort of the CPET. During CPET submaximal effort, we report a significant main effect for Test Minute and Group for VT and respiratory rate but no main effect of Group for E. To maintain adequate E during submaximal effort and decreased VT, higher respiratory rate was observed. CONCLUSIONS: These results suggest that diminished VT in subacute stroke patients may limit performance during submaximal and peak effort of CPET. Rehabilitation professionals should consider methods for improving pulmonary function during stroke rehabilitation.