Impact of Vigorous-Intensity Physical Activity on Body Composition Parameters, Lipid Profile Markers, and Irisin Levels in Adolescents: A Cross-Sectional Study

Abstract

In adolescence, health status is influenced by several factors, including dietary pattern and physical activity (PA) which are crucial elements of lifestyle in terms of prevention and treatment of metabolic and chronic diseases. The current study aimed to explore the impact of the different intensity levels of PA along with the adherence to a Mediterranean diet (MD), on body composition indices and metabolic parameters in a cohort of adolescents, thereby investigating potential predictors of health behavior in youth. This cross-sectional study was carried out among 92 participants (44 girls and 48 boys, aged 14 to 17 years), which were divided into the following three groups according to intensity levels of PA: Group A (physical inactivity), Group B (moderate PA), and Group C (vigorous-intensity PA). The Questionnaire of Adherence to the Mediterranean Diet (KIDMED test) was used to assess both diet composition and adherence to a MD. All subjects underwent anthropometric measurements, bio-impedentiometric analysis for body composition parameters, and biochemical and hormonal measurements. The majority of adolescents (60.87%) had a medium adherence to the MD, and even a better distribution of food rates was found in adolescents performing vigorous-intensity PA. A comparison of anthropometric measurements and body composition parameters among groups showed that body mass index and fat mass (FM) were significantly lower while body cell mass (BCM), free fat mass (FFM), phase angle (PhA), and total body water (TBW) were higher in Group C adolescents as compared with those of Group A. In Group C, insulin resistance (HOMA-IR) was reduced and insulin levels were inversely associated with FFM (r = -0.454 and p = 0.004) and directly correlated with FM (r = 0.331 and p = 0.003). In the same Group C, we observed elevated serum irisin levels and lower lipid profile markers as compared with Group A. Interestingly, irisin negatively correlated with both total cholesterol (r = -0.428 and p = 0.04) and LDL (r = -0.468 and p = 0.02) in Group C. Finally, a receiver operator characteristic curve (ROC) analysis revealed irisin, LDL, HDL, and body composition variables (FFM, BMC, PhA, and TBW) as the most predictive measures for vigorous-intensity PA. Our results highlight the importance of developing healthy lifestyle programs that include improving the intensity of PA among a young population as a superior strategy for ensuring a better quality of life.

Keywords: Mediterranean diet; body composition; healthy lifestyle; irisin; lipid profile marker; physical activity.

Figure 1

Compliance with items from the KIDMED test in the total sample, girls and boys. The radar chart plots the values of each item of Mediterranean diet score along a separate axis that starts in the center of the chart (0% compliance) and ends at the outer ring (100% compliance). The KIDMED score (M ± SD) and frequency (%) of the population adherent to each recommendation are reported in the table. Statistical differences were evaluated by Chi-squared tests. p < 0.05, girls vs. boys.

Figure 2

Compliance with items from the KIDMED test in the three physical activity groups (Group A, B and C). The radar chart plots the values of each item of Mediterranean diet score along a separate axis that starts in the center of the chart (0% compliance) and ends at the outer ring (100% compliance). The KIDMED score (M ± SD) and frequency (%) of the population adherence to each recommendation are reported in the table. Statistical differences were evaluated by Chi-squared tests. p < 0.05, * Group A vs. Group C; ° Group B vs. Group C; § Group A vs. Group B.

Figure 3

Correlations between insulin and FFM (kg) or FM (kg) in Group C. Association of insulin with FFM (kg) (A) or FM (kg) (B) were analyzed by Pearson’s correlation test. For each linear regression graph, the linear equation (y), the correlation coefficient (r), and the statistical significance (p) are reported.

Figure 4

Correlations of irisin with total cholesterol and LDL in Group C. Association of irisin with total cholesterol (A) or LDL (B) were analyzed by Pearson’s correlation test. For each linear regression graph, the linear equation (y), the correlation coefficient (r), and the statistical significance (p) are reported.

Figure 5

Receiver operating characteristic (ROC) curves of irisin, LDL, HDL, BMI, FFM, BCM, PhA, and TBW as predictors of vigorous-intensity physical activity. Graphic evaluation of irisin, LDL, HDL, BMI, FFM, BCM, PhA, and TBW with respect to physical activity (Group C vs. Group A), showing the true-positive rate (sensitivity) and the false-positive rate (specificity) of the analysis as a function of all possible cut-points for the analyzed markers. The analysis was performed with ROC curves, as described in the Statistical Analysis Section.