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Author Spotlight: Exploring the Impact of Reduced Resistance Exercise Volume on Metabolic Health
Published on: December 1, 2023
Cardiorespiratory Fitness, Physical Activity, and Insulin Resistance in Children
Eero A Haapala, Petri Wiklund, Niina Lintu1
1Institute of Biomedicine, School of Medicine, University of Eastern Finland, Kuopio, FINLAND.
Insights
Higher body fat percentage in children is linked to increased insulin resistance, especially with low physical activity or high sedentary time. Cardiorespiratory fitness, adjusted for lean mass, did not show a significant association with insulin resistance.
Area of Science:
- Pediatric endocrinology
- Exercise physiology
- Metabolic health
Background:
- Insulin resistance in children is a growing concern, often linked to obesity.
- Few studies have examined the combined effects of cardiorespiratory fitness (CRF) and body fat percentage (BF%) on insulin resistance.
- Understanding these relationships is crucial for developing effective prevention strategies.
Purpose of the Study:
- To investigate the independent and combined associations of CRF and BF% with insulin resistance in children aged 6-8 years.
- To explore the interactions of CRF and BF% with physical activity (PA) and sedentary time in relation to insulin resistance.
- To determine how different measures of CRF (scaled by lean body mass vs. body mass) relate to insulin resistance.
Main Methods:
- Cardiorespiratory fitness (CRF) assessed via maximal cycle ergometer test, with maximal power output (Wmax) scaled by lean body mass (LM) and body mass (BM).
- Body fat percentage (BF%) and LM measured using dual-energy X-ray absorptiometry.
- Insulin resistance assessed by fasting serum insulin and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR).
- Physical activity (PA) and sedentary time measured using a combined movement and heart rate sensor.
Main Results:
- BF% was directly associated with higher insulin and HOMA-IR.
- Wmax scaled by BM, but not LM, was inversely associated with insulin and HOMA-IR.
- Children with higher BF% and lower moderate-to-vigorous PA (MVPA) or higher sedentary time exhibited the highest insulin and HOMA-IR levels.
- CRF adjusted for LM was not significantly associated with glucose, insulin, or HOMA-IR.
Conclusions:
- Higher body fat percentage in children is a significant risk factor for insulin resistance.
- The combination of high BF% with low physical activity or high sedentary time exacerbates insulin resistance.
- Cardiorespiratory fitness, when appropriately adjusted for body composition (lean mass), may not be a primary determinant of insulin resistance in this age group.
Purpose:
Few studies have investigated the independent and joint associations of cardiorespiratory fitness (CRF) and body fat percentage (BF%) with insulin resistance in children. We investigated the independent and combined associations of CRF and BF% with fasting glycemia and insulin resistance and their interactions with physical activity (PA) and sedentary time among 452 children age 6 to 8 yr.
Methods:
We assessed CRF with a maximal cycle ergometer exercise test and used allometrically scaled maximal power output (Wmax) for lean body mass (LM) and body mass (BM) as measures of CRF. The BF% and LM were measured by dual-energy X-ray absorptiometry, fasting glycemia by fasting plasma glucose, and insulin resistance by fasting serum insulin and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). The PA energy expenditure, moderate-to-vigorous PA (MVPA), and sedentary time were assessed by combined movement and heart rate sensor.
Results:
Wmax/LM was not associated with glucose (β = 0.065, 95% confidence interval [CI] = -0.031 to 0.161), insulin (β = -0.079, 95% CI = -0.172 to 0.015), or HOMA-IR (β = -0.065, 95% CI = -0.161 to 0.030). Wmax/BM was inversely associated with insulin (β = -0.289, 95% CI = -0.377 to -0.200) and HOMA-IR (β = -0.269, 95% CI = -0.359 to -0.180). The BF% was directly associated with insulin (β = 0.409, 95% CI = 0.325 to 0.494) and HOMA-IR (β = 0.390, 95% CI = 0.304 to 0.475). Higher Wmax/BM, but not Wmax/LM, was associated with lower insulin and HOMA-IR in children with higher BF%. Children with higher BF% and who had lower levels of MVPA or higher levels of sedentary time had the highest insulin and HOMA-IR.
Conclusions:
Children with higher BF% together with less MVPA or higher levels of sedentary time had the highest insulin and HOMA-IR. Cardiorespiratory fitness appropriately controlled for body size and composition using LM was not related to insulin resistance among children.
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