ECSS Paris 2023: CP-PN02
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.
Read CV Berk EvanECSS Paris 2023: CP-PN02
INTRODUCTION: We recently reported that carbonation of water reduces beverage consumption compared to non-carbonated water, likely due to sensory effects such as oral stimulation. However, despite this reduction, hydration efficiency as assessed by changes in body weight and plasma volume was comparable to that of plain water. These findings suggest that carbonated water may offer similar hydration benefits to plain water, even when consumed in smaller volumes. However, the previous study was conducted under conditions where food intake was restricted. Since hydration occurs through both food and fluid consumption, it is practically important to investigate whether carbonation of water affects both drinking and eating behaviour, as well as hydration status, following exercise in the heat. METHODS: Twelve healthy young adults (six women) exercised at 50% of their peak oxygen uptake in a hot environment (35 °C) until they reached a 2% reduction in body mass. They then rested in a seated position in a cooler environment (25 °C) and were given a 30-min ad libitum eating and drinking period. During this time, participants were allowed to consume either non-carbonated or carbonated water, along with a standardized food item (bread). In the non-carbonated water trial, participants consumed non-carbonated water during the 30-min period, whereas in the carbonated water trial, they consumed carbonated water. The two trials were conducted on separate days. Venous blood and urine samples were collected throughout the protocol. RESULTS: In the carbonated water trial, fluid intake during the first 5 min after the onset of drinking was lower than in the non-carbonated water trial. Total fluid intake also tended to be lower under the carbonated water condition, whereas no difference was observed in total food intake between the two conditions. Cumulative urine volume did not differ between the water and carbonated water conditions. However, the degree of body mass recovery was lower in the carbonated water condition. In contrast, recovery of plasma volume and plasma osmolality was comparable between conditions. The carbonated water condition elicited a greater sensation of drinking-related stimulation and a greater reduction in hunger. CONCLUSION: Carbonated water reduces total fluid intake after exercise in the heat without affecting eating behavior, ultimately impairing the recovery of body fluid compared with the condition in which non-carbonated water is consumed. This attenuated recovery of body fluid with carbonated water contrasts with our previous study, in which participants followed the same protocol but did not consume food. In the present study, the inclusion of food particularly due to its sodium content may have helped retain ingested water in the body, a response that was absent in our earlier study. On the other hand, carbonated water intake suppresses hunger sensation, which may be beneficial for avoiding excessive calorie intake.
Read CV Naoto FujiiECSS Paris 2023: CP-PN02
INTRODUCTION: Muscle function is regulated by multiple hydroelectrolytic mechanisms that modulate cel-lular volume and extend beyond isolated plasma electrolyte concentrations. In particular, cellular hydration status and membrane-related properties are critical for muscle contrac-tility and functional performance. However, the contribution of integrated hydration and electrolyte regulation profiles to muscle function in older adults remains insufficiently understood. Objective: To identify which physiological domains of hydroelectrolytic reg-ulation are most strongly associated with muscle strength and functional performance in community-dwelling older adults METHODS: A cross-sectional study was conducted in 96 community-dwelling individuals aged ≥70 years. Markers of cellular hydration and membrane integrity were assessed using bioelec-trical impedance analysis, together with plasma and urinary sodium and chloride con-centrations. Principal component analysis (PCA) was applied to identify integrated phys-iological patterns of hydroelectrolytic regulation. Associations between these patterns and muscle strength (handgrip) and functional performance (Timed Up and Go test) were ex-amined, adjusting for sex and fat-free mass RESULTS: Three principal components describing distinct domains of hydroelectrolytic regulation were identified. The first component (F1) reflected an integrated renal–cellular pattern linking urinary sodium and chloride excretion with markers of cellular hydration. The second component (F2) was predominantly characterized by plasma electrolyte concentra-tions, while the third component (F3) was mainly associated with cellular hydration and volume parameters. Both F1 and F3 were independently associated with greater muscle strength and better functional performance, whereas F2 showed no independent associa-tion CONCLUSION: Integrated hydroelectrolytic regulation profiles related to cellular hydration—either com-bined with renal electrolyte excretion or predominantly intracellular—were independently associated with muscle strength and functional performance in older adults. In contrast, plasma electrolyte concentrations alone were not independently associated, underscoring the relevance of multidimensional hydration assessment beyond isolated biochemical markers.
Read CV Isabel LorenzoECSS Paris 2023: CP-PN02