title: Predicting Heart Rate at the Ventilatory Threshold for Aerobic Exercise Prescription in Persons With Chronic Stroke.
abstract: OBJECTIVE
  Treadmill aerobic exercise improves gait, aerobic capacity, and cardiovascular health after stroke, but a lack of specificity in current guidelines could lead to underdosing or overdosing of aerobic intensity. The ventilatory threshold (VT) has been recommended as an optimal, specific starting point for continuous aerobic exercise. However, VT measurement is not available in clinical stroke settings. Therefore, the purpose of this study was to identify an accurate method to predict heart rate at the VT (HRVT) for use as a surrogate for VT.
  
  
  METHODS
  A cross-sectional design was employed. Using symptom-limited graded exercise test (GXT) data from 17 subjects more than 6 months poststroke, prediction methods for HRVT were derived by traditional target HR calculations (percentage of HRpeak achieved during GXT, percentage of peak HR reserve [HRRpeak], percentage of age-predicted maximal HR, and percentage of age-predicted maximal HR reserve) and by regression analysis. The validity of the prediction methods was then tested among 8 additional subjects.
  
  
  RESULTS
  All prediction methods were validated by the second sample, so data were pooled to calculate refined prediction equations. HRVT was accurately predicted by 80% HRpeak (R, 0.62; standard deviation of error [SDerror], 7 bpm), 62% HRRpeak (R, 0.66; SDerror, 7 bpm), and regression models that included HRpeak (R, 0.62-0.75; SDerror, 5-6 bpm).
  
  
  CONCLUSIONS
  Derived regression equations, 80% HRpeak and 62% HRRpeak, provide a specific target intensity for initial aerobic exercise prescription that should minimize underdosing and overdosing for persons with chronic stroke. The specificity of these methods may lead to more efficient and effective treatment for poststroke deconditioning.Video Abstract available for more insights from the authors (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A114).
authors.affiliation: Department of Rehabilitation Sciences (P.B., S.B., B.R., D.C., K.D.), Department of Environmental Health (P.B., J.K., K.D.), Departments of Internal Medicine and Cardiology (M.G.), and Department of Neurology and Rehabilitation Medicine (B.K.), University of Cincinnati, Cincinnati, Ohio; and Division of Biostatistics and Epidemiology (J.K.), Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
authors.forename: Pierce
authors.initials: P
authors.lastname: Boyne
authors.forename: Sarah
authors.initials: S
authors.lastname: Buhr
authors.forename: Bradley
authors.initials: B
authors.lastname: Rockwell
authors.forename: Jane
authors.initials: J
authors.lastname: Khoury
authors.forename: Daniel
authors.initials: D
authors.lastname: Carl
authors.forename: Myron
authors.initials: M
authors.lastname: Gerson
authors.forename: Brett
authors.initials: B
authors.lastname: Kissela
authors.forename: Kari
authors.initials: K
authors.lastname: Dunning
mesh_terms: D000328:Adult; D000368:Aged; D015308:Anaerobic Threshold / Q000502:physiology*; D002908:Chronic Disease / Q000534:rehabilitation; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods*; D005081:Exercise Therapy / Q000592:standards*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D000071939:Stroke Rehabilitation