Impact of Dietary Intake and Cardiorespiratory Fitness on Glycemic Variability in Adolescents: An Observational Study.

Background: Cardiorespiratory fitness (CRF), estimated by maximum oxygen consumption (VO max) during exercise, is worsening among adolescents and associated with a decline in metabolic health into adulthood. Glycemic patterns may provide a mechanism between CRF and health.

Objectives: This study assessed the feasibility of measuring glycemic patterns using continuous glucose monitoring (CGM) in adolescents, aged 14-22 y, to estimate the relationship between VO max and glucose patterns.

Methods: Healthy adolescents ( = 30) were recruited for a treadmill VO max test and to complete the following activities for 7-10 d: ) wear a Dexcom G6 CGM, ) complete ≥3 24-h dietary recalls, and ) complete 1 at-home oral glucose tolerance test (OGTT, 75 g glucose). Glycemic patterns were extracted as mean glucose, the coefficient of variance, the mean amplitude of glycemic excursions, and the mean of daily differences. The 2-h glucose responses to the OGTT and individual meals were extracted. Statistical analyses evaluated the relationship between VO max and ) overall glycemic patterns and ) the maximum glucose level and AUC response to OGTT and meals, stratified by sex.

Results: Participant feasibility demonstrated that 90% completed CGM data ( = 27), 87% ≥7 d of CGM data ( = 26), 97% attempted OGTT ( = 29), and 93% completed ≥3 dietary recalls ( = 28). Most participants had normal BMI (70%) with an even distribution of sex (44% male). Males exhibited an inverse relationship between VO max and overall mean glucose (ß= -7.7, = 0.04). Males demonstrated an inverse relationship between VO max and ) maximum glucose (ß = -29, = 0.006) and AUC (ß = -2702, = 0.001) in response to the OGTT and ) AUC (ß = -1293, = 0.03) in response to meals. No association was observed between VO max and glucose patterns in females.

Conclusions: A sex-specific relationship between VO max and glycemic patterns was observed, suggesting a unique metabolic capacity during late adolescence by sex.This trial was registered at clinicaltrials.gov as NCT05845827.