PMID 27274107

Research
All papers

Greater effects of high- compared with moderate-intensity interval training on cardio-metabolic variables, blood leptin concentration and ratings of perceived exertion in obese adolescent females

Racil G, Coquart JB, Elmontassar W, Haddad M, Goebel R, Chaouachi A, Amri M, Chamari K

Question

Do high-intensity versus moderate-intensity interval training programs have different effects on cardiometabolic health, body composition, blood leptin, and perceived exertion after maximal testing in obese adolescent females?

Summary

This randomized 12-week school-region study compared high-intensity interval running, moderate-intensity interval running, and no training in obese adolescent females. Both interval programs used repeated 15-second efforts with 15-second active recovery, three days per week, and progressed from 3 x 4-minute blocks to 3 x 8-minute blocks. HIIT used 100% maximal aerobic speed during work intervals, while MIIT used 80% maximal aerobic speed; both recovered at 50% MAS. Both exercise groups improved body composition, VO2max, blood pressure, glucose-insulin markers, leptin, and RPE after maximal exercise. HIIT produced larger percentage changes in several body composition and insulin-related measures and a larger reduction in RPE after maximal testing. Attendance was complete and no training- or test-related injuries were reported.

Methodology

  • Healthy obese female adolescents recruited from three schools.
  • 47 participants.
  • Outdoor track running.
  • Work intervals: 15 seconds at 100% MAS.
  • Recovery: 15 seconds at 50% MAS within blocks; 3 minutes passive recovery between blocks.
  • Intensity: 100% maximal aerobic speed during work intervals.
  • Approximately 46-58 minutes depending on training phase, including warm-up, interval blocks, between-block recoveries, and cool-down.
  • 3 sessions per week.
  • 12 weeks.
  • Randomized controlled intervention with HIIT, MIIT, and non-exercising control groups.
  • Body composition, VO2max, Blood pressure and rate-pressure product, and Glucose-insulin markers were tracked.

Outcomes

Body composition

Body mass, BMI Z-score, and body fat decreased in both training groups; waist circumference decreased significantly only in HIIT. HIIT showed greater percentage changes than MIIT and control for body mass, body fat, and waist circumference.

Waist circumference within HIIT p=0.017; percentage-change between-group table reports p<0.05 markers for HIIT versus MIIT and control for body mass, body fat, and waist circumference.

Improved

VO2max

Absolute VO2max increased in both HIIT and MIIT.

HIIT +2.22 +/- 2.99%, p=0.019, ES=0.48; MIIT +3.57 +/- 1.39%, p=0.010, ES=0.57; both differed from control in between-group comparison.

Improved

Blood pressure and rate-pressure product

Resting heart rate, systolic blood pressure, diastolic blood pressure, and rate-pressure product decreased significantly in both training groups.

RPP p=0.013, ES=0.53 for HIIT and p=0.036, ES=0.46 for MIIT; table marks HRrest, SBP, DBP, and RPP as significantly different from pre-test.

Improved

Glucose-insulin markers

Blood glucose, insulin, and HOMA-IR decreased in both training groups; HIIT showed greater percentage changes than MIIT for insulin and HOMA-IR.

Table marks within-group changes at p<0.05; percentage changes: insulin HIIT -25.68 +/- 4.24% versus MIIT -19.40 +/- 6.23%, HOMA-IR HIIT -28.74 +/- 4.69% versus MIIT -22.58 +/- 6.72%, with HIIT significantly different from MIIT and control.

Improved

Blood leptin

Blood leptin decreased significantly in both training groups, with no HIIT-versus-MIIT superiority indicated in percentage change.

HIIT -22.31 +/- 6.58%, p=0.021, ES=0.67; MIIT -23.20 +/- 10.18%, p=0.012, ES=0.72; both differed from control.

Improved

RPE after maximal exercise test

RPE measured 30 minutes after graded exercise testing decreased in both training groups, with larger percentage reduction after HIIT.

HIIT -28.97 +/- 6.18%, p=0.001, ES=0.76; MIIT -14.38 +/- 8.70%, p=0.017, ES=0.57; HIIT significantly different from MIIT and control in percentage change.

Improved

Attendance and injury

Both training groups attended all sessions, and no participant complained or reported training- or test-related injury.

Improved

Insights

  • Short 15-second work/15-second recovery intervals can be scaled across weeks by increasing total block duration.
  • For obese adolescent females, both high- and moderate-intensity interval formats improved cardiometabolic outcomes under structured track-based conditions.
  • HIIT may add extra benefit for body composition, insulin-related measures, and perceived exertion after maximal testing compared with the same interval structure at moderate intensity.

Limitations

  • Population limited to obese adolescent females.
  • No long-term follow-up after the 12-week program.
  • Training supervision and exact session fidelity monitoring are not fully described.
  • Protocol depends on MAS testing and outdoor track running.
  • The study does not directly test home, app-led, or bodyweight HIIT.

Safety

  • Participants in HIIT and MIIT attended all training sessions.
  • No participant complained or reported any training- or test-related injury.
  • Participants with chronic diseases and obesity drug or therapy use were excluded.