pH Buffering Does not Influence BDNF Responses to Exercise

The influence of acidosis on brain-derived neurotrophic factor (BDNF) was examined by buffering pH changes during 10 min of continuous low intensity (LIE) and following high intensity cycling exercise to exhaustion (HIE). 11 athletes participated in 2 trials separated by 1 week. Individuals received either a placebo infusion (isotonic saline) or an isotonic sodium bicarbonate infusion before and during exercise. Blood samples were drawn at rest, after LIE and after HIE, as well as 3, 6, 10 and 15 min post exercise. During placebo trial, HIE induced a profound decrease (p < 0.01) of capillary blood bicarbonate concentration (HCO3-), pH, base excess (BE) and pCO(2). Higher (p < 0.01) HCO3-, pH and BE were found during bicarbonate infusion and post exercise in comparison to the placebo trial. Exercise induced an identical increase of blood lactate concentration in both trials. Serum BDNF concentration was increased (p < 0.01) at the end of HIE and remained elevated until 3 min post exercise in both trials. The present study suggests that during HIE lactate might have an acidosis-independed impact on BDNF secretion because buffering of blood gases, that attenuate the fall of pH but not the accumulation of lactic acid, failed to alter the exercise-induced increase of BDNF.