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Visa fullständig version : Ökad exogen kolhydratoxidation under träning av arginin, men inte av glutamin


King Grub
2011-11-04, 09:15
The addition of L: -arginine or L: -glutamine to glucose-electrolyte solutions can increase intestinal water, glucose, and sodium absorption in rats and humans. We evaluated the utility of L: -arginine and L: -glutamine in energy-rehydration beverages through assessment of exogenous glucose oxidation and perceptions of exertion and gastrointestinal distress during endurance exercise. Eight cyclists rode 150 min at 50% of peak power on four occasions while ingesting solutions at a rate of 150 mL 15 min(-1) that contained (13)C-enriched glucose (266 mmol L(-1)) and sodium citrate ([Na(+)] 60 mmol L(-1)), and either: 4.25 mmol L(-1) L: -arginine or 45 mmol L(-1) L: -glutamine, and as controls glucose only or no glucose. Relative to glucose only, L: -arginine invoked a likely 12% increase in exogenous glucose oxidation (90% confidence limits: ±8%); however, the effect of L: -glutamine was possibly trivial (4.5 ± 7.3%). L: -Arginine also led to very likely small reductions in endogenous fat oxidation rate relative to glucose (12 ± 4%) and L: -glutamine (14 ± 4%), and relative to no glucose, likely reductions in exercise oxygen consumption (2.6 ± 1.5%) and plasma lactate concentration (0.20 ± 0.16 mmol L(-1)). Effects on endogenous and total carbohydrate oxidation were inconsequential. Compared with glucose only, L: -arginine and L: -glutamine caused likely small-moderate effect size increases in perceptions of stomach fullness, abdominal cramp, exertion, and muscle tiredness during exercise. Addition of L: -arginine to a glucose and electrolyte solution increases the oxidation of exogenous glucose and decreases the oxygen cost of exercise, although the mechanisms responsible and impact on endurance performance require further investigation. However, L: -arginine also increases subjective feelings of gastrointestinal distress, which may attenuate its other benefits.

Eur J Appl Physiol. 2011 Nov 3. L: -Arginine but not L: -glutamine likely increases exogenous carbohydrate oxidation during endurance exercise.