PMID 29511662

Research
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Impact of a 12-week high-intensity interval training without caloric restriction on body composition and lipid profile in sedentary healthy overweight/obese youth

Khammassi M, Ouerghi N, Hadj-Taieb S, Feki M, Thivel D, Bouassida A

Question

Does 12 weeks of running-based 30:30 HIIT without caloric restriction improve body composition, aerobic capacity, and lipid profile in sedentary overweight or obese young men?

Summary

In sedentary overweight or obese young men, 12 weeks of progressive 30:30 running HIIT improved weight-related measures and between-group changes in aerobic capacity, total cholesterol, and triglycerides without a calorie-restriction program. The final analyzed sample was small and safety/adherence outcomes were not reported.

Methodology

  • Healthy untrained overweight or obese males aged 18-21 years with BMI >=25 kg/m2.
  • 16 participants.
  • Running.
  • Work intervals: 30 seconds.
  • Recovery: 30 seconds active recovery.
  • Intensity: Work at 100% maximal aerobic velocity; active recovery at 50% maximal aerobic velocity.
  • Warm-up plus 15-27 minutes of 30:30 intervals; cool-down was not clearly reported.
  • 3 sessions per week.
  • 12 weeks.
  • Randomized controlled pre/post intervention.
  • Body composition, Aerobic capacity, and Lipid profile were tracked.

Outcomes

Body composition

Weight, BMI, waist circumference, and body fat percentage changes favored HIIT over control.

Delta weight -3.9 +/- 3.2; delta BMI -1.2 +/- 1.0, p<0.01; delta body fat -1.6 +/- 1.3, p<0.05; delta waist -5.0 +/- 3.6, p<0.01.

Improved

Aerobic capacity

Within-group pre/post changes were not significant, but changes in maximal aerobic velocity and estimated VO2max were significantly better than control.

Delta MAV and delta VO2max differed between HIIT and control, p<0.01; HIIT delta MAV 1.5 +/- 1.0 and delta VO2max 4.8 +/- 3.8 vs control -0.3 +/- 0.5 and -1.1 +/- 1.9.

Improved

Lipids

Total cholesterol and triglyceride changes favored HIIT; LDL and HDL did not significantly change.

Delta total cholesterol 2.7 +/- 19.1 control vs -24.9 +/- 25.5 HIIT, p<0.05; delta triglycerides 3.9 +/- 40.5 control vs -38.6 +/- 27.2 HIIT, p<0.05.

Mixed

Insights

  • A 30:30 running format with MAV-based intensity is a concrete youth/young-adult HIIT template.
  • The study supports weight and lipid improvements without prescribed caloric restriction, but diet and daily activity were not recorded.
  • The protocol is more applicable to supervised track or school settings than unsupervised home workouts.

Limitations

  • Small analyzed sample.
  • Male-only overweight/obese young adult sample.
  • Food intake and daily physical activity outside sessions were not recorded.
  • VO2max was estimated from a field test rather than directly measured.
  • Safety, adherence, and dropout reasons were not reported.

Safety

  • Participants were informed of potential risks and gave written consent.
  • The article did not report adverse events, injuries, adherence, or dropout reasons.
  • Four of 20 enrolled participants were not represented in the final analyzed results.