Lean Mass Loss and Altered Muscular Aerobic Capacity after Bariatric Surgery.

Zhou N; Scoubeau C; Forton K; Loi P; Closset J; Deboeck G; Moraine JJ;
Klass M; Faoro V

Obesity Facts. 15(2):248-256, 2022.

INTRODUCTION: Patients undergoing weight loss surgery do not improve their
aerobic capacity or peak oxygen uptake (VO2peak) after bariatric surgery
and some still complain about asthenia and/or breathlessness. We
investigated the hypothesis that a post-surgery muscular limitation could
impact the ventilatory response to exercise by evaluating the post-surgery
changes in muscle mass, strength, and muscular aerobic capacity, measured
by the first ventilatory threshold (VT).

METHODS: Thirteen patients with obesity were referred to our university
exercise laboratory before and 6 months after bariatric surgery and were
matched by sex, age, and height to healthy subjects with normal weight.
All subjects underwent a clinical examination, blood sampling, and body
composition assessment by dual-energy X-ray absorptiometry, respiratory
and limb muscle strength assessments, and cardiopulmonary exercise testing
on a cyclo-ergometer.

RESULTS: Bariatric surgery resulted in a loss of 34% fat mass, 43%
visceral adipose tissue, and 12% lean mass (LM) (p < 0.001). Absolute
handgrip, quadriceps, or respiratory muscle strength remained unaffected,
while quadriceps/handgrip strength relative to LM increased (p < 0.05).
Absolute VO2peak or VO2peak/LM did not improve and the first VT was
decreased after surgery (1.4 +/- 0.3 vs. 1.1 +/- 0.4 L min-1, p < 0.05)
and correlated to the exercising LM (LM legs) (R = 0.84, p < 0.001).

CONCLUSIONS: Although bariatric surgery has numerous beneficial effects,
absolute VO2peak does not improve and the weight loss-induced LM reduction
is associated to an altered muscular aerobic capacity, as reflected by an
early VT triggering early exercise hyperventilation.