Lactic acidosis, potassium, and the heart rate deflection point in professional road cyclists. Issue 2 (1st April 2002)

• Record Type: Journal Article
• Authors: Lucía, A; Hoyos, J; Santalla, A; Pérez, M; Carvajal, A; Chicharro, J L
• Is Part Of: British journal of sports medicine. Volume 36:Issue 2(2002)
• Page Start: 113
• Page End: 117
• Publication Date: 2002-04-01
• Subjects: anaerobic threshold -- Conconi test -- cycling -- heart rate -- ramp test; HR, heart rate -- HRDP, heart rate deflection point -- AT, anaerobic threshold -- LVEF, left ventricular ejection fraction -- ECG, electrocardiogram -- RCP, respiratory compensation point -- LT, lactate threshold -- OBLA, onset of blood lactate accumulation; Sports medicine -- Periodicals; 617.1027
• DOI: 10.1136/bjsm.36.2.113
• Languages: English
• ISSNs: 0306-3674

Abstract

Abstract : Objective: To determine the influence of lactic acidosis, the Bohr effect, and exercise induced hyperkalaemia on the occurrence of the heart rate deflection point (HRDP) in elite (professional) cyclists. Methods: Sixteen professional male road cyclists (mean (SD) age 26 (1) years) performed a ramp test on a cycle ergometer (workload increases of 5 W/12 s, averaging 25 W/min). Heart rate (HR), gas exchange parameters, and blood variables (lactate, pH, P50 of the oxyhaemoglobin dissociation curve, and K + ) were measured during the tests. Results: A HRDP was shown in 56% of subjects at about 88% of their maximal HR (HRDP group; n = 9) but was linear in the rest (No-HRDP group; n = 7). In the HRDP group, the slope of the HR-workload regression line above the HRDP correlated inversely with levels of K + at the maximal power output ( r = −0.67; p<0.05). Conclusions: The HRDP phenomenon is associated, at least partly, with exercise induced hyperkalaemia.