PMID 30562948

Research
All papers

Effect of High-Intensity Interval Training Combined with L-Citrulline Supplementation on Functional Capacities and Muscle Function in Dynapenic-Obese Older Adults

Buckinx F, Gouspillou G, Carvalho LP, Marcangeli V, El Hajj Boutros G, Dulac M, Noirez P, Morais JA, Gaudreau P, Aubertin-Leheudre M

Question

Does L-citrulline supplementation enhance functional capacity and muscle-function gains from a 12-week HIIT program in dynapenic-obese older adults?

Summary

In dynapenic-obese older adults, 12 weeks of supervised elliptical HIIT improved functional capacity and muscle function in both supplement groups. Adding 10 g/day L-citrulline produced extra gains in some upper-limb strength and fast Timed Up & Go outcomes compared with placebo.

Methodology

  • Community-dwelling older adults with dynapenia and obesity from the Greater Montreal area.
  • 56 participants.
  • Elliptical exercise plus daily oral L-citrulline.
  • Work intervals: 30-second high-intensity sprints.
  • Recovery: 90-second moderate-intensity sprints.
  • Intensity: High intervals at 80-85% HRmax or Borg >17; recovery at about 65% HRmax or Borg 13-16.
  • 30 minutes: 5-minute warm-up, 20-minute HIIT, 5-minute cool-down.
  • 3 sessions per week on non-consecutive days.
  • 12 weeks.
  • Secondary analysis of a double-blind randomized placebo-controlled trial in which all participants received HIIT and were randomized to L-citrulline or placebo.
  • Functional capacity, Muscle strength and quality, and Body composition were tracked.

Outcomes

Functional capacity and muscle function

Both groups improved functional capacity and muscle function after 12 weeks of HIIT.

Within-group improvements were reported for most functional/muscle variables, with broad responder rates above 80% for functional capacities.

Improved

Added effect of L-citrulline

HIIT plus L-citrulline produced larger gains than HIIT plus placebo for fast Timed Up & Go and upper-limb strength outcomes.

Between-group effects: fast-paced Timed Up & Go p = 0.04; upper limb muscle strength p = 0.05; relative upper limb muscle strength p = 0.05.

Improved

Body composition

Waist circumference decreased in both groups, while group-specific fat and lean mass changes were mixed and not clearly different between groups.

HIIT + citrulline decreased total/android/leg fat mass; HIIT + placebo increased total lean mass; no clear between-group body composition effect.

Mixed

Insights

  • Elliptical HIIT may be a lower-impact option for older adults with dynapenic obesity.
  • Nutritional co-interventions can complicate attribution of benefits to HIIT alone.
  • Functional capacity may be a more relevant outcome than body composition for older dynapenic-obese users.

Limitations

  • Secondary analysis of a larger trial.
  • Relatively small sample and likely underpowered for some secondary outcomes.
  • Placebo group was older at baseline, although analyses adjusted for age.
  • No L-citrulline-only group.
  • No sex-specific analysis.
  • Special older dynapenic-obese population limits generalizability.

Safety

  • Sessions were supervised by trained health professionals and participants were screened by PAR-Q.
  • The article described 90% adherence in discussion and required at least 80% session completion for analysis.
  • Specific adverse events were not reported in the paper.