Ventilatory responses at submaximal exercise intensities in healthy children and adolescents during the growth spurt period: a semi-longitudinal study

Changes in Breathing Reserves During Growth in Healthy Untrained Boys and Girls

Background: The assessment of breathing reserve (BR) is essential to determine if ventilatory function is limited during exercise. Few studies reported the values of BR in healthy children and adolescents of both sexes. This study aimed to analyze the effects of age and sex on changes in BR in healthy untrained children and adolescents during growth. Methods: A study was conducted in 186 healthy untrained children and adolescents (10-16 years old). Maximal ventilation (V ˙ Emax) and maximal oxygen uptake (V ˙ O2max) were measured during a maximal graded test. Forced vital capacity and forced expiratory volume in 1 s (FEV1) were also measured. BR was expressed as a percentage of theoretical maximal voluntary ventilation (MVV) which was obtained by multiplying FEV1 by 35. The data were assessed by one-way analysis of variance (ANOVA) and two-way ANOVA supplement a Newman-Keuls test when P was significant (P < 0.05). Results: Height, weight, and lean body mass increased between 11 and 16 years old. For boys,  V ˙ O2max, V ˙ Emax, FEV1, and MVV increased (P < 0.05) between 12 and 16 years. For girls, V ˙ O2max increased (P < 0.05) only between 11 and 12 and 14 and 15 years. Increases in V ˙ Emax, FEV1, and MVV were observed between 10 and 12 years and stabilized afterward. The BR in girls was higher than in boys (P < 0.05). There were no significant differences in BR at the same age correlated with sex during growth. Discussion: No significant changes were observed in BR as a function of age. BR changes during growth seem to be independent of changes in anthropometric characteristics.

Improvement of adiponectin in relation to physical performance and body composition in young obese males subjected to twenty-four weeks of training programs

Obesity and related metabolic diseases represent a worldwide health problem. The main factor predisposing to obesity is an unhealthy lifestyle including the lack of physical activity. A pivotal role in the etio-pathogenesis of obesity is carried out by adipose tissue, an endocrine organ secreting several adipokines involved in numerous metabolic and inflammatory processes. Among these, of particular importance is adiponectin, an adipokine involved in the regulation of insulin sensibility and in anti-inflammatory processes. The aim of the study was to determine the effects of 24 weeks of two different training programs polarized (POL) and threshold training (THR) on body composition, physical capacities and adiponectin expression. Thirteen male obese subjects (BMI: 32.0 ± 3.0 kg m-2) followed 24 weeks of two different training programs, POL and THR, consisting of walking or running (or a combination of the two methods) in their normal living conditions. Before (T0) and after the end of the program (T1), the assessment of body composition was assessed by bioelectrical impedance and the concentration of salivary and serum adiponectin was analyzed by enzyme-linked immunosorbent assay and western blotting. Although the results obtained did not show significant differences between the two training programs, body mass and body mass index decreased by a mean of -4.46 ± 2.90 kg and 1.43 ± 0.92 kg m^-2 (P < 0.05). Fat mass decreased by -4.47 ± 2.78 kg (P < 0.05). V'O₂max increased by a mean of 0.20 ± 0.26 L min^-1 (P < 0.05) Also, we observed an increase in saliva and in serum of adiponectin concentrations at T1 compared to T0 by 4.72 ± 3.52 μg mL^-1 and 5.22 ± 4.74 ng mL^-1 (P < 0.05) respectively. Finally, we found significant correlations between Δ serum adiponectin and Δ Hip (R = -0.686, P = 0.001) and between Δ salivary adiponectin and ΔWaist (R = -0.678, P = 0.011). Our results suggest that a 24 weeks training program, independently from intensity and volume, induces an amelioration of body composition and fitness performance. These improvements are associated with an increase in total and HMW adiponectin expression in both saliva and in serum.

Energy Expenditure Estimation in Children, Adolescents and Adults by Using a Respiratory Magnetometer Plethysmography System and a Deep Learning Model

PURPOSE

Energy expenditure is a key parameter in quantifying physical activity. Traditional methods are limited because they are expensive and cumbersome. Additional portable and cheaper devices are developed to estimate energy expenditure to overcome this problem. It is essential to verify the accuracy of these devices. This study aims to validate the accuracy of energy expenditure estimation by a respiratory magnetometer plethysmography system in children, adolescents and adults using a deep learning model.

METHODS

Twenty-three healthy subjects in three groups (nine adults (A), eight post-pubertal (PP) males and six pubertal (P) females) first sat or stood for six minutes and then performed a maximal graded test on a bicycle ergometer until exhaustion. We measured energy expenditure, oxygen uptake, ventilatory thresholds 1 and 2 and maximal oxygen uptake. The respiratory magnetometer plethysmography system measured four chest and abdomen distances using magnetometers sensors. We trained the models to predict energy expenditure based on the temporal convolutional networks model.

RESULTS

The respiratory magnetometer plethysmography system provided accurate energy expenditure estimation in groups A (R² = 0.98), PP (R² = 0.98) and P (R² = 0.97). The temporal convolutional networks model efficiently estimates energy expenditure under sitting, standing and high levels of exercise intensities.

CONCLUSION

Our results proved the respiratory magnetometer plethysmography system's effectiveness in estimating energy expenditure for different age populations across various intensities of physical activity.