8% des sportifs doivent éviter les glucides avant un effort

[Nutrimuscle-Conseils]

Association between pre-exercise food ingestion timing and reactive hypoglycemia: Insights from a large database of continuous glucose monitoring data
Andrea Zignoli European Journal of Sport Science 2023

Using a large database of continuous glucose monitoring (CGM) data, this study aimed to gain insights into the association between pre-exercise food ingestion timing and reactive hypoglycemia. A group of 6,761 users self-reported 48,799 pre-exercise food ingestion events and logged minute-by-minute CGM, which was used to detect reactive hypoglycemia (<70 mg/dL) in the first 30 min of exercise. A linear and a non-linear binomial logistic regression model was used to investigate the association between food ingestion timing and the probability of experiencing reactive hypoglycemia. An analysis of variance was conducted to compare the predictive ability of the models.

On average, reactive hypoglycemia was detected in 8.34 ± 3.04% of the total events, with <15% of individuals experiencing hypoglycemia in >20% of their events. The majority of the reactive hypoglycemia events were found with pre-exercise food timing between ∼30 and ∼90 min, with a peak at ∼60 min. The superior accuracy (62.05 vs 45.1%) and F-score (0.75 vs 0.59) of the non-linear vs the linear model were statistically superior (P < 0.0001). These results support the notion of an unfavourable 30-to-90 min pre-exercise food ingestion time window which can significantly impact the likelihood of reactive hypoglycemia in some individuals.

HIGHLIGHTS
Large datasets of self-reported continuous glucose monitoring and food events are used here for the first time to get insights into reactive hypoglycemia, a condition often regarded as negative for endurance performance events

Using a binomial non-linear logistic regression model, the association between pre-exercise food ingestion timing and reactive hypoglycemia revealed the presence of an unfavourable window, when reactive hypoglycemia is more likely to occur.

Results confirm an individual predisposition to reactive hypoglycemia and, for 8 in 100 individuals, the pre-exercise food ingestion timing can meaningfully impact the likelihood of experiencing reactive hypoglycemia.

[Nutrimuscle-Conseils]

Effects of the Timing of Carbohydrate Intake on Metabolism and Performance in Soccer Players
by Ki-Woong Noh Nutrients 2023, 15(16), 3610;

This study aims to provide information to improve the performance of athletes comparing the effects of carbohydrate–electrolyte intake before and during exercise on metabolism and performance in soccer players. The study had a single-blind cross-over design. Drust’s protocol is a soccer-specific intermittent exercise test.

The carbohydrate–electrolyte intake experiments were divided into three timings: first, pre-exercise; second, half-time; and third, mixed. Eight participants were included in the data analysis (age: 21.32 ± 1.19 years; BMI: 22.69 ± 1.91 kg/m2; height: 176.5 ± 7.52 cm; weight: 69.5 ± 9.18 kg; Vmax: 16.75 0.71 km/h). The results of the mixed test showed a significantly lower respiratory exchange ratio than those of the placebo and half-time tests (p < 0.05). The mixed test showed significantly more fat oxidation than the half-time test (p < 0.05). The running times are placebo (422.13 ± 133.44 s) and mixed (677.38 ± 217.75 s), and the distances are placebo (1577.25 ± 517.02 m) and mixed (2530.00 ± 832.71 m) (p < 0.05). The mixed test showed a significantly lower rating of perceived exertion than the placebo test (p < 0.05). Carbohydrate oxidation and heart rate showed no significant differences between the experiments (p > 0.05). The exercise protocol in this study showed the metabolic response of soccer players to intermittent high-intensity exercise and subsequent endurance exercise.

In conclusion, it can be seen that the intake of carbohydrate–electrolytes improves the performance of soccer players, and the effect varies depending on the timing of carbohydrate–electrolyte intake.

[Nutrimuscle-Diététique]

Traduction de l'étude

Effets du moment de l'apport en glucides sur le métabolisme et les performances des joueurs de football
par Ki-Woong Noh Nutrients 2023, 15(16), 3610 ;

Cette étude vise à fournir des informations pour améliorer les performances des athlètes en comparant les effets de l'apport en glucides et en électrolytes avant et pendant l'exercice sur le métabolisme et les performances des joueurs de football. L'étude avait une conception croisée en simple aveugle. Le protocole de Drust est un test d’effort intermittent spécifique au football.

Les expériences d'apport en glucides et en électrolytes ont été divisées en trois moments : premièrement, avant l'exercice ; deuxièmement, la mi-temps ; et troisièmement, mixte. Huit participants ont été inclus dans l'analyse des données (âge : 21,32 ± 1,19 ans ; IMC : 22,69 ± 1,91 kg/m2 ; taille : 176,5 ± 7,52 cm ; poids : 69,5 ± 9,18 kg ; Vmax : 16,75 ± 0,71 km/h). Les résultats du test mixte ont montré un taux d'échange respiratoire significativement inférieur à ceux des tests placebo et mi-temps (p < 0,05). Le test mixte a montré significativement plus d’oxydation des graisses que le test à mi-temps (p < 0,05). Les temps de course sont placebo (422,13 ± 133,44 s) et mixtes (677,38 ± 217,75 s), et les distances sont placebo (1577,25 ± 517,02 m) et mixtes (2530,00 ± 832,71 m) (p < 0,05). Le test mixte a montré une évaluation de l'effort perçu significativement inférieure à celle du test placebo (p < 0,05). L'oxydation des glucides et la fréquence cardiaque n'ont montré aucune différence significative entre les expériences (p > 0,05). Le protocole d'exercice de cette étude a montré la réponse métabolique des joueurs de football à des exercices intermittents de haute intensité et à des exercices d'endurance ultérieurs.

En conclusion, on peut constater que la consommation de glucides et d’électrolytes améliore les performances des joueurs de football, et que l’effet varie en fonction du moment de la consommation de glucides et d’électrolytes.