title: Left ventricular volumes and hemodynamic responses to postexercise ischemia in healthy humans.
abstract: OBJECTIVE
  The purpose of this study was to determine the cardiac mechanisms involved in cardiovascular adjustments during postexercise circulatory occlusion (OCCL).
  
  
  METHODS
  Heart rate (HR), mean arterial pressure (MAP), left ventricular end-diastolic (EDV) and end-systolic volumes (ESV), stroke volume (SV), cardiac output (CO), and total peripheral vascular resistance (total peripheral resistance (TPR)) were assessed in nine healthy volunteers during rest and static exercise at 30% of maximum voluntary contraction followed by either OCCL for 3 min or non-OCCL in a randomized crossover protocol.
  
  
  RESULTS
  During handgrip, HR (+20%; P < 0.001), CO (+11%; P = 0.003), MAP (+18%; P = 0.001), and TPR (+6%; P = 0.004) increased, SV (-8%; P = 0.001) and EDV (-5%; P < 0.001) decreased, while ESV did not change (P > 0.05). These responses were similar between conditions (P > 0.05). During OCCL, HR, SV, and CO returned to baseline, whereas MAP (+19%; P < 0.001) and TPR (+9%; P = 0.004) remained elevated. EDV (+12%; P < 0.001) and ESV (+23%; P < 0.001) increased in parallel above resting values.
  
  
  CONCLUSIONS
  Activation of muscle metaboreceptors during OCCL increased MAP by elevating TPR. Despite the higher afterload and increased ESV, CO and SV were kept similar to resting values because EDV also increased, implying the involvement of the Frank-Starling mechanism.
authors.affiliation: Department of Physiology, Instituto Biomédico, Universidade Federal Fluminense, Niterói, RJ, Brazil.
authors.forename: B G
authors.initials: BG
authors.lastname: Bastos
authors.forename: J W
authors.initials: JW
authors.lastname: Williamson
authors.forename: T
authors.initials: T
authors.lastname: Harrelson
authors.forename: A C
authors.initials: AC
authors.lastname: Nóbrega
mesh_terms: D000328:Adult; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure; D002302:Cardiac Output / Q000502:physiology*; D004452:Echocardiography; D015444:Exercise / Q000502:physiology*; D006439:Hemodynamics; D006801:Humans; D007511:Ischemia / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction; D016277:Ventricular Function, Left