Impact of fluid ingestion on neuromuscular function and performance during prolonged exercise: A comparative analysis of hydration states

Abstract

Prolonged exercise, particularly in endurance sports, is known to exacerbate both central and peripheral fatigue, negatively impacting neuromuscular function. Dehydration accelerates these effects, impairing the ability of muscles to generate force and diminishing motor output from the central nervous system. This study investigates the role of fluid ingestion in mitigating the decline in neuromuscular function during extended exercise. Twenty healthy, recreationally active male participants aged 18-30 years completed two exercise trials - one with fluid ingestion and the other without. Participants cycled for two hours at 65% of their maximum heart rate in both hydrated (HYD) and dehydrated (DEHYD) conditions. Neuromuscular function was assessed using maximal voluntary contraction (MVC), electromyography (EMG), and the central activation ratio (CAR). Results showed significant declines in MVC, EMG, and CAR in the DEHYD condition compared to the HYD condition. Body mass loss and urine specific gravity also indicated greater dehydration in the DEHYD trial. Fluid ingestion was found to preserve neuromuscular function by maintaining blood volume, electrolyte balance, and thermoregulation. This study highlights the critical importance of hydration strategies for athletes, as fluid ingestion significantly reduces both central and peripheral fatigue during prolonged exercise, ultimately improving endurance performance.