Author(s): HAWKINS, S., GARDINER, C., HOMER, A., FAZACKERLEY, L., MOULTON, C., WEAKLEY, J., KARAGOUNIS, L., HAWKINS, S., BERK, E., JOHNSTON, R., LEOTA, J., MITCHELL, L., HALSON, S., Institution: UNILEVER, Country: UNITED STATES, Abstract-ID: 2580

INTRODUCTION:
Exercise-induced dehydration can negatively impact mood and cognitive performance. Solutions containing electrolytes and glucose (sugar) are commonly used to support rehydration and mitigate cognitive decrements, potentially due to the role of glucose in energy provision. However, previously published findings from the present trial demonstrate that sugar-free electrolyte formulations are effective rehydration strategies.
METHODS:
Thirty participants enrolled and 22 participants (n = 18 F; n = 4 M) completed a double-blinded, randomized, placebo-controlled, crossover trial. As previously reported, participants completed an exercise-induced dehydration protocol (30°C, 50% rh) to elicit ~2% body mass loss (1.70 ± 0.29%), followed by a 60-minute rehydration period providing 150% of fluid lost using three electrolyte rehydration formulations (A = allulose, B = blend of amino acids, C = sugar alcohol) or placebo (flavour-matched water). Mood was assessed as a secondary outcome using four visual analogue scales (thirst, fatigue, positivity of mood, readiness to perform) and cognitive performance was assessed as a secondary outcome using a three-minute Psychomotor Vigilance Task and a two-minute Simon task. Assessments were completed hourly across the five-hour recovery period.
RESULTS:
Perceptual responses did not differ between conditions (p > 0.05; d <0.20; trivial effects). On the PVT, mean reaction time was slower for placebo compared with Formula A at three hours (p = 0.020, d = 0.12 [0.04, 0.21]) and Formula B at one hour (p = 0.025, d = 0.12 [0.04, 0.21]), with median reaction time mirroring this pattern for placebo versus Formula B at one hour (p = 0.024, d = 0.12 [0.04, 0.21]). No differences were observed for transformed number of lapses (p > 0.05). On the Simon task, placebo demonstrated slower overall and congruent mean reaction time compared with Formula A at two hours (p = 0.029, d = 0.12 [0.03, 0.20]), with no differences observed for remaining outcomes (p > 0.05).
CONCLUSION:
Cognitive performance following exercise-induced dehydration was largely comparable across conditions, with some small positive effects observed for sugar-free electrolyte formulations. When considered alongside the previously reported hydration outcomes, these findings suggest that sugar-free hydration solutions can effectively support rehydration without compromising post-exercise cognitive performance. Direct comparisons with sugar-containing formulations and assessment under more cognitively demanding conditions, such as decision-making tasks or dehydration resulting in greater than 2% body mass loss, may help further clarify the efficacy of sugar-free electrolyte solutions for mood and cognitive performance.