# Distinct lipidomic profiles but similar improvements in aerobic capacity following sprint interval training versus moderate-intensity continuous training in male adolescents PMID: 39949665 Journal: Frontiers in physiology Published: 2025 Authors: Su W, Liu J, Wang A, Zhang H, Sun Y, Yan Z, Svensson M, Yu JG, Zhao L ## Question Do 6 weeks of SIT and MICT produce different aerobic-capacity, serum lipoprotein, and serum lipidomic adaptations in healthy untrained male adolescents? ## Summary This randomized school-based laboratory study compared 6 weeks of cycling sprint interval training with moderate continuous cycling in healthy untrained male adolescents. Both programs similarly improved VO2peak, while standard blood lipids and body composition did not significantly change. Targeted lipidomics showed different serum lipid adaptations: SIT mainly reduced five free fatty acids, whereas MICT changed a broader set of sphingolipids and phospholipids. ## Population - Twenty-four healthy untrained male adolescents aged 12-14 years, randomized to SIT or MICT. - Sample size: 24 - Age: Mean 13.08 +/- 0.88 years; 12-14 years eligible - Sex: All male - Fitness level: Untrained; no regular physical training in the past year - Health status: Healthy adolescents without recent injury, chronic disease, or anti-inflammatory/immunosuppressive medicine use. ## Methodology - Randomized two-arm exercise training study with pre/post VO2peak, body composition, serum lipoprotein, and targeted lipidomic measures. - 6 weeks, 3 sessions per week. - Boarding-school adolescent sample with supervised cycle-ergometer training and laboratory testing. - Randomized and controlled study design. ## Protocol - SIT. - Modality: Cycle ergometer. - Work intervals: 30-second all-out cycling bouts. - Recovery: 4-minute rests between bouts. - Sets or repetitions: 4 bouts in weeks 1-2, 5 in weeks 3-4, 6 in weeks 5-6. - Intensity: All-out against resistance equal to 7.5% of body mass. - Session duration: Not explicitly summed; includes 10-minute warm-up and 10-minute cool-down. - Frequency: 3 days per week. - Program length: 6 weeks. - Progression: Bout count progressed from 4 to 6 across the intervention. - MICT. - Modality: Cycle ergometer. - Work intervals: Continuous cycling. - Intensity: 65% of VO2peak. - Session duration: 30 minutes weeks 1-2, 45 minutes weeks 3-4, 60 minutes weeks 5-6, plus 10-minute warm-up and 10-minute cool-down. - Frequency: 3 days per week. - Program length: 6 weeks. - Progression: Continuous cycling duration progressed from 30 to 60 minutes. ## Outcomes ### VO2peak Status: improved Both SIT and MICT significantly improved VO2peak with no meaningful between-group difference. Time effect F(1,44) = 14.75, p < 0.001; group p = 0.65; interaction p = 0.97. ### Serum clinical lipids and fasting glucose Status: no clear change Standard serum total cholesterol, triglycerides, HDL-C, LDL-C, and fasting glucose did not significantly change within or between groups. ### SIT lipidomic profile Status: mixed SIT significantly decreased five free fatty acids. 5 of 276 lipids changed; FDR <0.05 and FC <1/1.5. ### MICT lipidomic profile Status: mixed MICT significantly changed 28 lipids, with 7 increased and 21 decreased, mainly sphingolipids and phospholipids. 28 of 276 lipids changed; FDR <0.05 and FC >1.5 or <1/1.5. ## Practical Insights - A short 30-second sprint format with long rests can improve VO2peak in healthy untrained male adolescents under supervision. - Similar aerobic gains do not imply identical metabolic adaptations. - All-out adolescent sprint training is not a casual unsupervised prescription. ## Limitations - Small sample of 24 participants. - Male-only adolescent sample. - No non-exercise control group. - Short intervention and no long-term follow-up. - Nutrition was not tracked in detail. - Some lipidomic quantification methods require cautious interpretation. ## Safety And Adherence - No adverse events were reported. - All 24 adolescents completed testing and training. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/39949665/) (pubmed) - [DOI](https://doi.org/10.3389/fphys.2025.1475391) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11821953/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.