PMID 36820014

Research
All papers

Effects of 12-week combined training versus high intensity interval training on cardiorespiratory fitness, body composition and fat metabolism in obese male adults

D'Alleva M, Vaccari F, Graniero F, Giovanelli N, Floreani M, Fiori F, Marinoni M, Parpinel M, Lazzer S

Question

Does a combined high-intensity interval plus moderate continuous training protocol produce similar fitness, body composition, and fat-metabolism effects as energy-matched HIIT in obese male adults?

Summary

In inactive obese adult men, 12 weeks of home-based run/walk HIIT improved body mass, fat mass, cardiorespiratory fitness, and fat-oxidation outcomes. A combined protocol with fewer HIIT intervals plus moderate continuous exercise produced similar benefits with lower heart rate and perceived exertion but longer session duration.

Methodology

  • Healthy inactive obese male adults aged 18-50 years, BMI at least 30, without major cardiovascular, respiratory, neurologic, musculoskeletal, metabolic, or endocrine disease. Final groups were combined training n=18 and HIIT n=16.
  • 34 participants.
  • Outdoor running/walking on flat terrain.
  • Work intervals: 5-7 x 2 min high-intensity bouts.
  • Recovery: 1 min walking recovery.
  • Intensity: Work at speed corresponding to 95% VO2peak; recovery at 50% VO2peak.
  • Energy-matched to about 20 kJ/kg fat-free mass plus warm-up/cool-down.
  • 3 sessions/week.
  • 12 weeks.
  • Randomized 12-week comparative exercise intervention without inactive control
  • Body mass, BMI, waist, fat mass, and fat-free mass, Absolute and relative VO2peak, Fat oxidation rates and maximal fat oxidation intensity, and Heart rate, perceived exertion, session duration, distance were tracked.

Outcomes

Body composition

Both groups reduced body mass, BMI, waist, and fat mass with no significant group-by-time difference.

Improved

VO2peak

Absolute and fat-free-mass-normalized VO2peak increased in both groups by about 16% with no between-group difference.

Improved

Fat oxidation

Fat oxidation measures improved in both groups without a clear superiority of one protocol.

Improved

Training tolerance

Combined training produced lower mean HR and RPE but required longer duration and more distance than HIIT.

Mixed

Insights

  • Energy-matched HIIT and combined training can both improve fitness and fat-loss markers in screened obese men.
  • A combined protocol may be more tolerable because it lowers perceived exertion and heart rate, though it takes longer.
  • Remote HR monitoring can support home-based exercise delivery when in-person sessions are limited.

Limitations

  • No inactive control group.
  • Participants were healthy obese men without comorbidities, limiting clinical generalization.
  • Only one combined-training ratio was tested.
  • Remote real-life training introduced less control than laboratory delivery.
  • Dietary influences cannot be ruled out.

Safety

  • No adverse events occurred during the 12-week intervention. One person assigned to HIIT left before starting because heart disease was identified.