AEROBIC AND RESISTANCE TRAINING SHOW DIVERGENT ASSOCIATIONS WITH INSULIN SENSITIVITY AND SHORT-TERM GLYCEMIC EXPOSURE IN PREDIABETES: A CROSS-SECTIONAL STUDY

Abstract

ackground: Prediabetes is a reversible condition where lifestyle changes can prevent type 2 diabetes. While physical activity is crucial for management, traditional glycemic markers like HbA1c may not adequately reflect short-term exercise effects. Serum fructosamine, indicating average blood sugar levels over 1-3 weeks, is a more responsive biomarker but is under-researched in prediabetic populations, especially in the Gulf region. Aim: To evaluate the association between regular physical activity and short-term glycemic control, indexed by serum fructosamine, in adults with prediabetes, and to examine whether exercise modality (aerobic, resistance, or combined) differentially influences short-term and long-term glycemic indices, body composition, and insulin sensitivity. Methods: A cross-sectional analytical study at Thumbay Hospital and Thumbay Laboratories in Ajman, UAE, was conducted from November 2025 to April 2026, involving 78 adults aged 18–65 with prediabetes. Participants were stratified by physical activity levels using the IPAQ-SF. Various measurements, including anthropometric indices, fasting plasma glucose, HbA1c, fasting insulin, HOMA-IR, and serum fructosamine, were taken under standardized conditions. The Hemoglobin Glycation Index (HGI) was calculated based on the difference between observed and predicted HbA1c levels. Statistical analyses included Mann–Whitney U and Kruskal Wallis tests for between-group comparisons and Spearman's coefficient for correlations, with a significance level set at p < 0.05. Results: The study described a predominantly male (73.1%) and middle-aged cohort, with 82.1% classified as overweight or obese. Participants were 44.9% active and 55.1% sedentary, with no significant differences in fasting glucose, insulin, HOMA-IR, HbA1c, fructosamine, or BMI between the two groups. Within the active subgroup, aerobic exercisers (n = 13) had the lowest median BMI (25.7 kg/m²) and fasting insulin but the highest fructosamine levels. However, these differences diminished in multivariable regression models, indicating that male sex and BMI were key determinants of fasting insulin and HOMA-IR. Sedentary status was linked to higher HbA1c, while age correlated with higher fructosamine. Conclusions: Self-reported physical activity did not affect glycemic outcomes in prediabetics, probably owing to misclassification and limited exercise benefits. Despite the short sample size, exploratory analysis suggested that aerobic exercise may improve insulin sensitivity and body composition while resistance training may improve glycemic exposure. Combining exercise may be beneficial, requiring additional study. In equivocal HbA1c findings, short-term glycemic indicators are important, but the absence of serum albumin measurement and albumin adjustment for fructosamine in exercise group comparisons limits interpretations. Keywords. Prediabetes, physical activity, exercise modality, fructosamine, HbA1c, HOMA-IR, hemoglobin glycation index, short-term glycemic control, United Arab Emirates.