Hypothesis:
Weight gained in response to aerobic exercise represents an increase in lean mass.
Methods:
Participants from the exercise group (n=68) of the Inflammation and Exercise (INFLAME) study had fat mass, lean mass, and weight measured at baseline and at follow-up. Fat mass and lean mass were measured using DXA. Changes in lean mass and fat mass were quantified across tertiles of weight change in the exercise training group and were analyzed using generalized linear models with adjustment for baseline value.
Results:
are presented as least squares means with 95% confidence intervals. Results: Overall, participants exhibited a mean (range) weight change of –0.73 kg (–9.00, 7.00; n=68) following exercise training. Tertiles of mean (range) weight change were: tertile 1 (most weight loss) –3.40 kg (–9.00,–1.50; n=23), tertile 2 (some weight loss) –0.70 kg (–1.30, –0.10; n=22), and tertile 3 (weight gain) 1.93 kg (0, 7.00; n=23). For those in tertile 3, we observed a significant increase (p<0.0001) in lean mass of 0.91 kg (95% CI, 0.48, 1.34) compared to those who lost weight −0.85 kg (−1.28,−0.42) in tertile 1 and −0.52 kg (−0.97,−0.08) in tertile 2. However, no significant difference in lean mass change was seen between the two weight loss tertiles. We also observed a significant increase in fat mass in participants who gained weight (tertile 3) 1.07 kg (0.41, 1.73) while those who lost the most weight (tertile 1) −2.55 kg (−3.21,−1.89) had a significant decrease in fat mass. Participants who experienced some weight loss (tertile 2) showed no significant change in fat mass, −0.24 kg (−0.91, 0.44).
Conclusion:
Weight gained with aerobic exercise training cannot be attributed to increased lean mass only. Our findings suggest that adults who gained weight with exercise showed significant increases in both fat and lean mass.
Moderately High Protein Diets During Resistance/Aerobic Exercise Training Improve Body Composition Via Positive Changes in Adiposity But Not Lean Mass Accretion
