Amano Tatsuro, Sugiyama Yuki, Okumura Junya, Fujii Naoto, Kenny Glen P, Nishiyasu Takeshi, Inoue Yoshimitsu, Kondo Narihiko, Sasagawa Katsumi, Enoki Yasuaki, Maejima Daisuke
Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Niigata, Japan.
Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Japan.
Exp Physiol. 2019 Oct;104(10):1494-1504. doi: 10.1113/EP087843. Epub 2019 Aug 26.
What is the central question of this study? What are the effects of isomaltulose, an ingredient in carbohydrate-electrolyte beverages to maintain glycaemia and attenuate the risk of dehydration during exercise heat stress, on postexercise rehydration and physiological heat loss responses? What is the main finding and its importance? Consumption of a 6.5% isomaltulose-electrolyte beverage following exercise heat stress restored hydration following a 2 h recovery as compared to a 2% solution or water only. While the 6.5% isomaltulose-electrolytes increased plasma volume and plasma osmolality, which are known to modulate postexercise heat loss, sweating and cutaneous vascular responses did not differ between conditions. Consequently, ingestion beverages containing 6.5% isomaltulose-electrolytes enhanced postexercise rehydration without affecting heat loss responses.
Isomaltulose is a disaccharide carbohydrate widely used during exercise to maintain glycaemia and hydration. We investigated the effects of ingesting a beverage containing isomaltulose and electrolytes on postexercise hydration state and physiological heat loss responses. In a randomized, single-blind cross-over design, 10 young healthy men were hypohydrated by performing up to three 30 min successive moderate-intensity (50% heart rate reserve) bouts of cycling, each separated by 10 min, while wearing a water-perfusion suit heated to 45°C. The protocol continued until a 2% reduction in body mass was achieved. Thereafter, participants performed a final 15 min moderate-intensity exercise bout followed by a 2 h recovery. Following cessation of exercise, participants ingested a beverage consisting of (i) water only (Water), (ii) 2% isomaltulose (CHO-2%), or (iii) 6.5% isomaltulose (CHO-6.5%) equal to the volume of 2% body mass loss within the first 30 min of the recovery. Changes in plasma volume (ΔPV) after fluid ingestion were greater for CHO-6.5% compared with CHO-2% (120 min postexercise) and Water (90 and 120 min) (all P ≤ 0.040). Plasma osmolality remained elevated with CHO-6.5% compared with consumption of the other beverages at 30 and 90 min postexercise (all P ≤ 0.050). Urine output tended to be reduced with CHO-6.5% compared to other fluid conditions (main effect, P = 0.069). Rectal and mean skin temperatures, chest sweat rate and cutaneous perfusion did not differ between conditions (all P > 0.05). In conclusion, compared with CHO-2% and Water, consuming a beverage consisting of CHO-6.5% and electrolytes during recovery under heat stress enhances PV recovery without modulating physiological heat loss responses.
本研究的核心问题是什么？碳水化合物 - 电解质饮料中的一种成分异麦芽酮糖醇，在运动热应激期间用于维持血糖水平并降低脱水风险，它对运动后补液及生理散热反应有何影响？主要发现及其重要性是什么？与2%的溶液或仅饮水相比，运动热应激后饮用6.5%的异麦芽酮糖醇 - 电解质饮料，在2小时恢复期间可使机体恢复水合状态。虽然6.5%的异麦芽酮糖醇 - 电解质增加了血浆容量和血浆渗透压，而这两者已知可调节运动后的散热，但不同条件下出汗和皮肤血管反应并无差异。因此，摄入含6.5%异麦芽酮糖醇 - 电解质的饮料可增强运动后补液，且不影响散热反应。
异麦芽酮糖醇是一种二糖碳水化合物，在运动期间广泛用于维持血糖水平和水合状态。我们研究了摄入含异麦芽酮糖醇和电解质的饮料对运动后水合状态及生理散热反应的影响。在一项随机、单盲交叉设计中，10名年轻健康男性穿着加热至45°C的水灌注服，进行多达三轮、每轮30分钟的连续中等强度（50%心率储备）骑行，每轮间隔10分钟，直至体重减轻2%。此后，参与者进行最后一轮15分钟的中等强度运动，随后恢复2小时。运动结束后，参与者在恢复的前30分钟内摄入一种饮料，该饮料包括：（i）仅饮水（水组），（ii）2%的异麦芽酮糖醇（CHO - 2%组），或（iii）6.5%的异麦芽酮糖醇（CHO - 6.5%组），摄入量相当于体重减轻2%的体积。与CHO - 2%组（运动后120分钟）和水组（运动后90分钟和120分钟）相比，CHO - 6.5%组摄入液体后血浆容量变化（ΔPV）更大（所有P≤0.040）。与运动后30分钟和90分钟饮用其他饮料相比，CHO - 6.5%组血浆渗透压仍保持升高（所有P≤0.050）。与其他液体条件相比，CHO - 6.5%组尿量有减少趋势（主效应，P = 0.069）。不同条件下直肠温度、平均皮肤温度、胸部出汗率和皮肤灌注无差异（所有P>0.05）。总之，与CHO - 2%组和水组相比，在热应激恢复期间饮用含6.5%异麦芽酮糖醇和电解质的饮料可增强血浆容量恢复，且不调节生理散热反应。
