Comparison of buffering capacities during isocapnic buffering phase between elite endurance and anaerobic competitors and their relationship to aerobic and anaerobic indexes

Abstract The aim of present study was to compare of buffering capacities during isocapnic buffering phase between elite endurance and anaerobic competitors and their relationship to aerobic and anaerobic indexes. Fourteen elite cyclist who were either anaerobic (n = 6) or aerobic competitors (n = 8) performed one standard incremental test and a supramaximal exercise test until exhaustion in 2 separated sessions. During incremental test respiratory gases were measured and arterial blood samples were collected for lactate, bicarbonate and pH measurements. Isocapnic buffering phase was defined as the time between lactate threshold and respiratory compensatory threshold. Bicarbonate buffering was identified via Δ[HCO3─]. Δ[PH─] and non-bicarbonate capacity was calculated from [Δ[LA─]. Δ[PH] ─] – [Δ[HCO3─]. Δ[PH─]] formula, respectively. Two independent sample t – test was used for all comparison between groups and the relationship between variables was measured by Person correlation test. Bicarbonate buffering capacity (p < 0.01), isocapnic buffering phase length (p < 0.05) and blood lactate changes during isocapnic buffering phase (p < 0.01) in aerobic competitors were significantly higher than anaerobic group. Significant correlation was found between bicarbonate buffering capacity and VO2max (p < 0.05) and non-bicarbonate buffering capacity and maximum accumulative oxygen deficiency (p< 0.01). Our results indicated that relative contribution of bicarbonate and non-bicarbonate buffers against lactic acid during isocapnic buffering phase is different between anaerobic and aerobic competitors and can be used for aerobic and anaerobic capacity prediction.