PMID 41933456

Research
All papers

Skeletal Muscle and Circulating microRNAs Adaptations to 12-Week HIIT With or Without L-Citrulline in Obese Older Adults

Mercier-Guery A, Millet M, Croset M, Marcangeli V, Dulac M, Carvalho LP, Hajj-Boutros G, Gaudreau P, Morais JA, Gouspillou G, Noirez P, Rousseau JC, Chapurlat R, Aubertin-Leheudre M

Question

Does 12 weeks of supervised HIIT, with or without L-citrulline supplementation, change muscle and circulating microRNA expression in older adults with obesity, and are those microRNA changes associated with clinical and biological adaptations?

Summary

In older adults with obesity who completed supervised elliptical HIIT, adding daily L-citrulline altered some muscle and blood microRNAs and those changes were linked with body composition, functional, muscle-power, IGF-1, leptin, adiponectin, and insulin-sensitivity changes. The paper is mechanistic and exploratory, so it is more useful for internal adaptation context than for making direct user-facing workout claims.

Methodology

  • Older men and women with obesity and/or dynapenia in a supervised HIIT trial subset
  • 68 participants.
  • Elliptical.
  • Work intervals: 30 seconds.
  • Recovery: 90 seconds.
  • Intensity: 80%-85% HRmax or Borg >17.
  • 30 minutes.
  • 3 times/week.
  • 12 weeks.
  • Secondary exploratory analysis of a double-blind randomized interventional trial
  • Muscle microRNA expression, Serum microRNA expression, and Body composition and metabolic associations were tracked.

Outcomes

Myo-microRNAs

Myo-microRNAs and muscle-related microRNAs were not altered by HIIT with or without citrulline.

No clear change

miR-504-5p

HIIT plus citrulline decreased muscle miR-504-5p compared with placebo and this correlated with lower body fat, better functional capacities, muscle power, and higher IGF-1.

p=0.022 for decrease; correlations around r=-0.6, p<0.05

Improved

Response biomarkers

Several muscle and serum microRNA changes were associated with favorable body composition, functional, metabolic, or hormone changes, but mostly in subgroup or association analyses.

Selected subgroup p values <=0.05

Mixed

Insights

  • For internal generation, 30-second hard efforts with 90-second recoveries are a documented older-adult elliptical structure when supervised.
  • The response to HIIT may vary by sex, age, BMI, dynapenic status, and supplement context; avoid one-size-fits-all claims.
  • This paper supports biomarker and adaptation context, not direct frontend promises.

Limitations

  • Secondary exploratory analysis
  • No nonexercise control or citrulline-only group
  • Small NGS and biopsy subsets
  • Multiple subgroup and association analyses
  • Device-logged work/power dose not available

Safety

  • No adverse event detail was reported in this secondary analysis.
  • Authors caution that external validity is limited to relatively healthy older adults with obesity and limited comorbidities.