Physical fitness, activity, and insulin dynamics in early pubertal children

Area of Science:

• Pediatric Endocrinology
• Metabolic Health
• Exercise Physiology

Background:

• Insulin dynamics, including insulin sensitivity (SI) and acute insulin response to glucose (AIRg), are crucial for metabolic health.
• Racial and ethnic variations in insulin dynamics are observed in pediatric populations, but underlying factors require elucidation.

Purpose of the Study:

• To investigate the independent effects of physical activity and cardiorespiratory fitness on insulin dynamics in diverse pediatric cohorts.
• To determine if observed racial/ethnic differences in insulin dynamics can be attributed to disparities in physical activity or fitness levels.

Main Methods:

• Utilized an intravenous glucose tolerance test (IVGTT) with minimal modeling to quantify insulin sensitivity index (SI) and acute insulin response to glucose (AIRg).
• Assessed cardiorespiratory fitness using VO2-170 and physical activity levels via accelerometry in European-, African-, and Hispanic-American children (aged 7-12 years).
• Employed multiple regression analyses to evaluate the contributions of fitness and physical activity to SI and AIRg, controlling for ethnicity.

Main Results:

• Cardiorespiratory fitness emerged as a more significant predictor of both insulin sensitivity (SI) and acute insulin response (AIRg) compared to physical activity, irrespective of participants' ethnicity.
• Statistical analyses indicated that racial/ethnic disparities in insulin dynamics were not statistically explained by differences in either physical activity or cardiorespiratory fitness levels.

Conclusions:

• Physical activity and cardiorespiratory fitness are independent determinants of insulin dynamics in children.
• Observed racial/ethnic differences in insulin dynamics among children are not accounted for by variations in physical activity or fitness, suggesting other contributing factors.