Is body fluid status affected by different electrolyte solutions during endurance cycling?

Abstract

Fatigue development in endurance sports has several causes; among these, dehydration can impair performance. Both water and electrolytes are lost during exercise, in particular, when exercising in hot environments. These losses must be replaced, with carbohydrate-electrolyte solutions, in different forms. This study aimed to evaluate the effects of different hydrating solutions on body fluid status. Nine male recreational cyclists performed three experimental trials on separate days: trials consisted of a two-hour endurance ride, with three different hydration solutions, consumed in a randomized order (water, water+powder, water+gel). Body weight was measured, and bioimpedance vector analysis was performed both before and after each trial. Changes from pre- to post-training in the impedance vector, phase angle, total body water and extracellular water were then compared between the three conditions, using MANOVA for repeated measures. A time × treatment effect was shown for the total body water (p=0.05) and impedance vector (p=0.032), with both the powder and gel differing from the water-only condition. Powder and gel solutions have been shown to be equally effective in limiting the negative effects of dehydration, preventing the loss of total body water. However, gels may represent a practical advantage for endurance athletes, especially those who take part in long-distance races.