Association between carbohydrate intake and physiological variables in recreational runners

Abstract

Road running is a widely practiced sport due to its accessibility and health benefits. Physiological and nutritional factors, such as carbohydrate intake, glycemic response, and body weight control, directly influence performance and physiological responses to exercise. This cross-sectional study aimed to evaluate blood glucose variation, body weight loss, and perceived exertion (RPE) in amateur runners, as well as to investigate their association with pre-exercise carbohydrate consumption. Twenty-six runners of both sexes were assessed before and after a running session. Body weight, capillary glucose, RPE, and self-reported carbohydrate intake were measured. Average body weight loss was 0.377 ±0.253 kg, significantly higher in men. Blood glucose averaged 109 ±29.7 mg/dL pre-exercise and 105 ±21.2 mg/dL post-exercise, indicating a slight reduction. Mean carbohydrate intake was 28.7 ±23.2 g, and RPE was slightly higher in women, with no significant difference. A moderate inverse correlation was observed between total carbohydrate intake and glycemic variation (r = -0.453; p=0.02), suggesting a protective effect of pre-exercise carbohydrate consumption on glycemic stability. These findings indicate that adequate carbohydrate intake before running supports glucose maintenance, reduces perceived exertion, and improves physiological responses, highlighting the importance of individualized nutritional guidance for recreational runners.