Exercise intensities and metabolic health: Targeting blood glucose, insulin, and C-peptide levels in adults with prediabetes in the postprandial state

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ObjectiveExercise improves postprandial glycemia and insulin sensitivity in individuals with prediabetes, but the optimal intensity for this metabolic regulation remains unclear. The current study explored the impact of various exercise intensities on blood glucose, insulin, and C-peptide levels in prediabetic individuals to identify the optimal intensity for improving these metabolic indicators. MethodsIn this crossover study, 25 individuals with prediabetes participated in exercise sessions at four different intensities 50 %, 60 %, 70 %, and 80 % of their predicted maximum heart rate using a treadmill. Each session lasted 30 min, including a 5-min warm-up and 5-min cool-down period. Blood samples were collected at four time points: during fasting, immediately before exercise, and 30 and 60 min post-exercise. These samples were analyzed for glucose, insulin, and C-peptide levels. The effects of exercise intensity on these parameters were evaluated using repeated measures analysis of variance (ANOVA), with post hoc tests conducted to determine specific differences between the intensities. ResultsThe participants had an average age of 34.88 years, mean height of 170 cm, and body mass index of 30.34 kg/m2. A significant reduction in insulin and glucose levels post-exercise was observed at 70 % intensity (p ≤ 0.001). Despite high fasting blood glucose levels (110–115 mg/dL), significant reductions were noted at 30 and 60 min post-exercise (p ≤ 0.001). Insulin levels approached near baseline at 70 % intensity, from fasting (26.74 ± 20.83) to 60 min post-exercise (28.47 ± 20.79), indicating a positive response at this intensity. C-peptide levels also showed significant changes, with 70 % intensity exercise bringing them closest to fasting levels by 60 min post-exercise. ConclusionThis study highlights the importance of exercise intensities in enhancing metabolic parameters in individuals with prediabetes. Specifically, 70 % of the predicted maximum heart rate was beneficial, optimizing insulin sensitivity and potentially reducing the risk of progressing from prediabetes to diabetes.