Lucía Mulas, AlejandroHoyos, J.Santalla Hernández, AlfredoPérez Ruiz, MargaritaCarvajal, AlfredoLópez Chicharro, José2016-09-052016-09-052002Lucía Mulas, A., Hoyos, J., Santalla Hernández, A., Pérez Ruiz, M. C., Carvajal, A., & Chicharro, J. L. (2002). Lactic acidosis, potassium, and the heart rate deflection point in professional road cyclists. British Journal of Sports Medicine, 36(2), 113-117.0306367414730480http://hdl.handle.net/11268/5702The aim of this study is 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. 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. 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). The HRDP phenomenon is associated, at least partly, with exercise induced hyperkalaemia.engjournal article10.1136/bjsm.36.2.113open accessCondición físicaCiclismoMedicina deportivaMedicina deportiva