Habitual carbohydrate ingestion reduces the efficacy of oral carbohydrate rinsing during repetitions to failure.

Carbohydrate mouth rinsing has been reported to enhance exercise performance although individual variation exists. The present study aimed to investigate the effect of habitual dietary carbohydrate intake on the efficacy of rinsing a 6% carbohydrate solution on the number of bench press repetitions to failure at 60% of 1‐RM. Twenty‐one recreationally active male participants (Mean ± SD) (age: 24 ± 4 years, height: 177.8 ± 7.8 cm, body mass: 78.6 ± 8.1 kg; bench press 1‐RM: 73.3 ± 20.5 kg) performed bench press repetitions to failure at 60% 1‐RM following rinsing with 25 mL of a 6% carbohydrate (CHO), an artificially sweetened solution (PLA) and a non‐rising control condition (CON) in a randomised cross‐over design. A 7‐day dietary record was completed prior to the first session and subsequently analysed for daily carbohydrate consumption. The number of repetitions performed during CHO (24 ± 4) was higher than CON [21 ± 4; p < 0.001; 95% CI: 1, 4; d = 0.64], as was PLA [23 ± 4; p = 0.002; 95% CI: 1, 3; d = 0.48]. However, there was a large, negative relationship [r = −0.68 (95% CI: −0.86, −0.36), p < 0.001] between daily relative carbohydrate intake (g kg−1) and the difference in the number of repetitions between CHO and PLA. The present study suggests the existence of an inverse relationship between daily carbohydrate ingestion and the efficacy of carbohydrate mouth rinsing; participants who consumed the most daily carbohydrate were generally less likely to see an increase in performance with carbohydrate rinsing. Highlights: The use of either carbohydrate or artificially sweetened mouth‐rinses are possible strategies to improve resistance exercise performance without the ingestion of energy, which can be helpful when trying to create a caloric deficit.Those who regularly consume larger amounts of carbohydrate in their diet may not report the same positive effects compared with those who generally consume less.Rinsing with an artificially sweetened solution reduces the exposure of teeth to sugar and potentially be beneficial for those with a history of dental problems such as sensitive teeth and/or enamel erosion. [ABSTRACT FROM AUTHOR]