Keto analogue and amino acid supplementation and its effects on ammonemia and performance under thermoneutral conditions.

Alterations of cerebral function, fatigue and disturbance in cognitive-motor performance can be caused by hyperammonemia and/or hot environmental conditions during exercise. Exercise-induced hyperammonemia can be reduced through supplementation with either amino acids or combined keto analogues and amino acids (KAAA) to improve exercise tolerance. In the present study, we evaluated KAAA supplementation on ammonia metabolism and cognitive-motor performance after high-intensity exercise under a low heat stress environment. Sixteen male cyclists received a ketogenic diet for 2 d and were divided into two groups, KAAA (KEx) or placebo (CEx) supplementation. The athletes performed a 2 h cycling session followed by a maximum test (MAX), and blood samples were obtained at rest and during exercise. Cognitive-motor tasks were performed before and after the protocol, and the exhaustion time was used to evaluate physical performance. The hydration status was also evaluated. The CEx group showed a significant increase (∼ 70%) in ammonia concentration at MAX, which did not change in the KEx group. The non-supplemented group showed a significant increase in uremia. Both the groups had a significant increase in blood urate concentrations at 120 min, and an early significant increase from 120 min was observed in the CEx group. There was no change in the glucose concentrations of the two groups. A significant increase in lactate was observed at the MAX moment in both groups. There was no significant difference in the exhaustion times between the groups. No changes were observed in the cognitive-motor tasks after the protocol. We suggest that KAAA supplementation decreases ammonia concentration during high-intensity exercise but does not affect physical or cognitive-motor performances under a low heat stress environment.

Estado de hidratação e desempenho cognitivo-motor durante uma prova de fast triathlon no calor / Hydration status and cognitive-motor performance during a fast triathlon race in the heat

O objetivo desse estudo foi avaliar o estado de hidratação e desempenho cognitivo-motor em atletas durante uma prova de fast triathlon no calor. Doze triatletas (34 ± 2,7 anos) participaram do trabalho. O estado de hidratação foi mensurado pela perda de massa corporal (MC), coloração e gravidade específica (GE) urinárias. O desempenho cognitivo-motor foi verificado pela coordenação motora (CM) e tempo de reação simples (TRS). Após a prova houve uma diminuição significativa da MC (1,8 %; P < 0,001). Um aumento significativo entre pré e pós-competição foi observado para o índice de coloração da urina (P < 0,001) e GE (P < 0,001), respectivamente. O TRS foi melhor após a prova. Porém, demonstraram dismetria, prejudicando sua CM. Conclui-se que níveis de desidratação foram observados entre os atletas após a prova. Alterações opostas foram encontradas quanto ao desempenho cognitivo-motor. Atletas demonstraram uma maior descoordenação motora, mas melhoraram seu tempo de reação.

The purpose of this study was to evaluate the hydration status and cognitive-motor performance in athletes during a fast triathlon race in the heat. Twelve triathletes (34 ± 2.7 years) participated in the study. Hydration status was measured by body mass (BM) loss, urine color and urine specific gravity (SG). The cognitive-motor performance was determined by motor coordination (MC) and simple reaction time (SRT). There was a significant decrease of BM (1.8 %; P < 0.001). A significant increase from pre race to post race was observed in urine color (P < 0.001) and SG (P < 0.001), respectively. The SRT was faster after race. However, athletes demonstrated dysmetria, impairing MC. It was concluded that dehydration levels were observed among athletes after race. Adverse changes were found on the cognitive-motor performance. Athletes demonstrated greater motor incoordination, but improved the reaction time.