Effect of Aerobic or Resistance Exercise, or Both, on Intermuscular and Visceral Fat and Physical and Metabolic Function in Older Adults With Obesity While Dieting.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 33839788 · doi:10.1093/gerona/glab111
What was done
Investigators conducted a randomized controlled trial comparing aerobic exercise (AEX), resistance exercise (REX), combination exercise (COMB), and a control group during matched ~10% diet-induced weight loss in 160 older adults with obesity. Prespecified 6-month endpoints included intermuscular adipose tissue (IMAT) and visceral adipose tissue (VAT) measured by MRI, insulin sensitivity index (ISI) from oral glucose tolerance testing, physical performance using the Modified Physical Performance Test (PPT), VO2peak, gait speed, and knee strength measured by dynamometry.
What was found
COMB decreased IMAT (-41%) and VAT (-36%) significantly more than AEX (-28% IMAT, -19% VAT) and REX (-23% IMAT, -21% VAT; p = .003 to .01). All exercise groups decreased IMAT and VAT more than control (between-group p < .001). ISI increased more in COMB (86%) than AEX (50%) and REX (39%; p = .005 to .03). PPT improved more in COMB than AEX and REX (p < .05). VO2peak improved more in COMB and AEX than REX, whereas knee strength improved more in COMB and REX than AEX (all p < .05). Reductions in IMAT and VAT correlated with improvements in PPT (r = -0.28 and -0.39), VO2peak (r = -0.49 and -0.52), gait speed (r = -0.25 and -0.36), and ISI (r = -0.49 and -0.52; all p < .05).
Why it matters
In dieting older adults with obesity, combining aerobic and resistance training provides superior ectopic fat reduction and captures the distinct functional and metabolic benefits of both exercise modalities.
Limits
The intervention lasted 6 months, leaving long-term maintenance and adherence unmeasured. The study was restricted to older adults undergoing caloric restriction and matched ~10% weight loss, so findings may not generalize to weight-stable or younger cohorts. The abstract does not report whether total exercise volume or energy expenditure was equated between the single-mode and combination arms.
Cited by
- contradicts Minute-for-minute over short durations such as 30 minutes per day, strength training leads to greater improvements in insulin sensitivity than aerobic training.