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Heart Rate Behavior And Changes In Hemodynamic Variables During 24h Continuous Cycle Ergometer Exercise: 2418Board #26 June 3 9:00 AM - 10:30 AM

Pokan, Rochus FACSM; Hochgatterer, Rainer; Ocenasek, Helmuth; Miehl, Martin; Vonbank, Karin; Würth, Sabine; Hofmann, Peter FACSM; von Duvillard, Serge P. FACSM; Smekal, Gerhard; Berent, Robert; Wonisch, Manfred FACSM

Medicine & Science in Sports & Exercise: May 2011 - Volume 43 - Issue 5 - p 653-654
doi: 10.1249/01.MSS.0000401810.42645.4e
E-23 Free Communication/Poster - Cardiac: JUNE 3, 2011 7:30 AM - 12:30 PM: ROOM: Hall B
Free

1Univ. of Vienna, Vienna, Austria. 2Center for Life Style Medicine, Linz, Austria. 3Medical University of Vienna, Vienna, Austria. 4University and Medical University of Graz, Vienna, Austria. 5College of Idaho, Caldwell, ID. 6Center for Cardiac Rehabilitation, Bad Schallerbach, Austria. 7Center for Cardiac Rehabilitation, St. Radegund, Austria.

Email: rochus.pokan@univie.ac.at

(No relationships reported)

PURPOSE: The aim of this study was to examine changes in hemodynamic variables during 24h cycle ergometer exercise.

METHODS: Seven male subjects (38 yrs, 180 cm) were monitored throughout 24h at a constant workload of 20 watt below their first lactate turn point (LTP1) at 174±10 W. Body mass (BM), heart rate (HR), oxygen consumption (VO2), systolic blood pressure (SBP), cardiac output (CO) and stroke volume (SV) using a non-invasive device (Innocor) and 2-D echocardiograms [M-mode measurement - left atrial (LAD), ventricular end-diastolic (EDD), end-systolic (ESD) diameters and shortening fraction (SF)] were obtained over the left parasternal area and venous blood samples were collected and analyzed for N-terminal pro-brain natriuretic peptide (NT-proBNP) and hematocrit (HCT) at the end of 1, 6 and 24 hours of cycle exercise.

RESULTS: BM (78.4±2.3, 78.0±2.2, 78.7±2.2 kg), HR (128±4, 140±3, 124±3 min-1),VO2 (34.5±1.6, 34.7±1.6, 35.1±1.5 ml·min-1·kg-1), SBP (162±7, 165±8, 161±7 mmHg), CO (17,4±0.5, 17.3±0.6, 17.6±0.7 l·min-1), SV (137±5, 123±5, 142±7 ml), LAD (36±2, 36±2, 41±2 mm), EDD (51±2, 49±1, 54±1 mm), ESD (30±2, 31±1, 31±1 mm), SF (40±3, 35±3, 42±3 %), NT-proBNP (30±5, 97±26, 569±146 pg·ml-1), and HCT (43.3±0.7, 44.4±0.5, 41.4±0.6 %). Significant correlations (p<0.05) were found between delta 6/24 values for HR and SV (r=-0.907), LAD (r = -0.814), SF (r = -0.853), BM and LAD (r = 0.814), SF (r = 0.784), and SV LAD (r = 0.777), SF (r =0.854).

CONCLUSIONS:Our study suggests that the decrease in HR during the 24 h aerobic exercise was due to hypervolemia and the associated ventricular workload that resulted in increases in SV and NT-proBNP as a consequence of increases in left ventricular diastolic dimension.

© 2011 American College of Sports Medicine