Skeletal Muscle and Circulating microRNAs Adaptations to 12-Week HIIT With or Without L-Citrulline in Obese Older Adults.
Plain-language summary
This study looked at how high-intensity interval training (HIIT) with or without L-citrulline (an amino acid that may boost blood flow and muscle health) affects tiny genetic regulators called microRNAs in muscle and blood of obese older adults. Researchers split 68 participants into two groups, one taking L-citrulline and the other a placebo, during a 12-week HIIT program, measuring changes in body composition, muscle function, and microRNA levels. While HIIT alone didn’t change certain muscle-specific microRNAs, it did alter others in ways tied to better fat loss, muscle power, and insulin sensitivity. Adding L-citrulline to HIIT was linked to lower levels of one muscle microRNA (miR-504-5p), which correlated with reduced body fat and improved performance.
Key findings
- HIIT alone did not change muscle-specific microRNAs (like miR-133a, -1, -206) but altered others linked to fat loss and muscle gains.
- L-citrulline with HIIT lowered muscle miR-504-5p, tied to less body fat and better function.
- Changes in certain microRNAs (like miR-744-5p, -151a-3p) tracked with lean mass gains or insulin sensitivity, depending on sex and frailty status.
How to analyze the study yourself
- Study type
- Randomized controlled trials directly compare interventions but may not reflect real-world diversity outside the study’s strict conditions.
- Population
- Older adults with obesity (average age 67); results may not apply to younger or non-obese adults.
- Funding
- Not reported
- Watch for
- This study found that HIIT reshaped some microRNAs in ways tied to better body composition and function in obese older adults, and adding L-citrulline may amplify certain benefits. If you’re over 60 and carrying extra weight, pairing HIIT with L-citrulline (a safe, over-the-counter amino acid) may be worth doing for muscle and metabolic health.