The effects of carbohydrate availability on cycling endurance at the maximal lactate steady state

Am J Physiol Regul Integr Comp Physiol. 2024 Jan 15. doi: 10.1152/ajpregu.00178.2023. Online ahead of print.ABSTRACTThe impacts of carbohydrate (CHO) availability on time to task failure (TTF) and physiological responses to exercise at the maximal lactate steady state (MLSS) have not been studied. Ten participants (3 females, 7 males) completed this double blinded, placebo-controlled study that involved a ramp incremental test, MLSS determination, and four TTF trials at MLSS, all performed on a cycle ergometer. Using a combination of nutritional (CHO [7g/kg] and placebo [PLA; 0g/kg] drinks) and exercise interventions (no exercise [REST] and glycogen reducing exercise [EX]), the four conditions were expected to differ in pre-exercise CHO availability (RESTCHO > RESTPLA > EXCHO > EXPLA). TTF at MLSS was not improved by CHO loading, as RESTCHO (57.1 [16.6] min) and RESTPLA (57.1 [15.6] min) were not different (p=1.00); however, TTF was ~50% shorter in EX conditions compared to REST conditions on average (p < 0.05), with EXCHO (39.1 [9.2] min) ~90% longer than EXPLA (20.6 [6.9] min; p < 0.001). There were effects of condition for all perceptual and cardiometabolic variables when compared at isotime (p<0.05) and TF (p<0.05), except for ventilation, perceptual responses, and neuromuscular function measures, which were not different at TF (p>0.05). Blood lactate concentration was stable in all conditions for participants who completed 30 min of exercise. Thes...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - Category: Physiology Authors: Source Type: research