PMID 39024345

Research
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Efficacy of high-intensity interval training versus continuous training on serum myonectin and lipid outcomes in adults with metabolic syndrome: A post-hoc analysis of a clinical trial

Petro JL, Fragozo-Ramos MC, Milán AF, Aristizabal JC, Calderón JC, Gallo-Villegas J

Question

Is supervised HIIT more effective than moderate continuous training for serum myonectin and lipid-related outcomes in adults with metabolic syndrome?

Summary

In adults with metabolic syndrome, 12 weeks of supervised treadmill HIIT was not superior to moderate continuous training for myonectin, lipid profile, free fatty acids, or intramuscular lipids. HIIT showed a small within-group increase in myonectin, but the study was a post-hoc analysis and several outcomes were exploratory.

Methodology

  • Adults aged 40-60 with metabolic syndrome.
  • 60 participants.
  • Treadmill.
  • Work intervals: 1 minute.
  • Recovery: 2 minutes at 50% VO2peak.
  • Intensity: 90% VO2peak.
  • 22 minutes including warm-up and cooldown.
  • 3 sessions/week.
  • 12 weeks.
  • Post-hoc analysis of a randomized clinical trial
  • Myonectin, Lipid profile, Intramuscular lipids, and Body composition were tracked.

Outcomes

Myonectin

HIIT was not superior to MICT, but HIIT showed a small within-group myonectin increase by robust estimation.

Between-group p=.661; HIIT robust within-group p=.042; paired t p=.055.

Mixed

Lipids

Lipid profile and free fatty acids did not significantly change in either group.

Between-group lipid and FFA p values were all >.05.

No clear change

Intramuscular lipids

IMCL, EMCL, and total intramuscular lipid did not significantly change in either group.

HIIT IMCL p=.893, EMCL p=.401, total p=.715; MICT IMCL p=.401, EMCL p=.929, total p=.735.

No clear change

Body composition

Both groups showed favorable body-composition signals, but between-group differences were not significant.

AFMI between-group p=.713; ALM p=.810.

Mixed

Insights

  • HIIT was shorter than MICT but did not produce superior lipid biomarker changes.
  • Biomarker-focused claims require larger primary trials.
  • Metabolic syndrome protocols should not be translated without clinical screening.

Limitations

  • Post-hoc analysis.
  • Possible type II error.
  • Small intramuscular lipid subsample.
  • Statin imbalance between groups.
  • Longer than 12 weeks may be needed for lipid outcomes.
  • Morning timing may have affected lipid results.

Safety

  • The article referred to the parent trial as reporting both interventions safe.
  • No article-specific adverse events were reported.