Acute Effects of Exercise on Metabolic, Inflammatory, and Immune Markers in Adolescent Girls with Normal Weight or Overweight/Obesity

Background: Obesity alters metabolic, inflammatory, and immune responses, and acute exercise may affect these parameters differently according to body composition. This study investigated the acute effects of Spartacus exercise on metabolic, inflammatory, and immune markers in adolescent girls with overweight/obesity and normal weight. Methods: In this non-randomized clinical study, sixteen girls with overweight/obesity (BMI: 31.17 ± 3.85 kg/m2) and fourteen normal-weight girls (BMI: 21.93 ± 0.99 kg/m2) performed an intermittent running test (15 s effort, 15 s passive recovery), starting at 7 km·h−1 with 1 km·h−1 increments every 3 min until exhaustion. Blood samples were collected at rest (T0), immediately post-exercise (T1), and 30 min post-exercise (T2). CRP and ESR were assessed at baseline to characterize participants’ inflammatory status, while glucose and leukocyte subpopulations were evaluated to investigate acute exercise responses. Results: Fasting glucose, lipid profile (TC, TG, HDL-C, LDL-C), inflammatory markers (CRP, ESR), and leukocyte subpopulations were assessed. Significant group effects were observed for all metabolic and inflammatory markers, reflecting higher baseline values in participants with overweight/obesity compared with normal-weight participants (p < 0.05). Significant effects of time were found for glucose and leukocytes (p < 0.001), indicating acute exercise-induced changes, along with significant time × group interactions. Participants with overweight/obesity showed greater and more prolonged increases in glucose, total leukocytes, and neutrophils, whereas normal-weight girls returned to baseline within 30 min. Conclusions: Acute high-intensity intermittent exercise induces transient metabolic and immune responses in adolescents, with amplified and prolonged effects in those with obesity. These findings highlight the importance of considering body composition when prescribing exercise programs.