Obesity, as an inflammatory state, can cause multi-organ disease, which often manifested in poor physical fitness involving the respiratory, cardio-vascular and muscles limitation. Bariatric surgery has become an important treatment option in severe obesity. The remarkably and rapid surgical weight loss, the obese patient gave feedback that they can walk further, but feels “no energy in his feet to speed up, when they need to run a few steps to catch the bus”. Had her physical condition already improved? Does weight loss after surgery equal improved physical condition? How does the heart, lungs, and muscles response to exercise? In order to search for the answer, we reviewed the previous relevant research, regarding the changes of postoperative aerobic capacity and we tried to discuss from a holistic perspective our observations.The thesis is divided into two modules including three studies.The first module including study 1 and 2, which are designed to identifies the determinants of the aerobic exercise capacity following weight loss reduced by bariatric surgery. We turn the daily problems feedback from obese patients who underwent bariatric surgery into three scientific questions:- What is the impact of adipose tissue on determinants of aerobic exercise capacity?- What is the impact of bariatric surgery on determinants of aerobic exercise capacity?- Do obese patients return to normal after bariatric surgery?Based on the limited knowledge and experience of predecessors about how obesity influences exercise pulmonary hemodynamics, the second module including study 3, which are designed to further analysed the right ventricle - pulmonary circulation during exercise and to answer the following question:- how does obesity affect right ventricular, pulmonary circulation and gas exchange adaptation during exercise?To answer these questions, we recruited 29 obese subjects and paired to age-, sex- and height- matched 29 healthy controls. A subgroup of thirteen patients who underwent bariatric surgery were retested 6 months after surgery and compared with theirs controls. Then, we comprehensive analysed the results of following tests: blood test, clinical assessment, body composition analysis, muscle strength measurements, pulmonary function (spirometry and diffusion capacity), exercise stress echocardiography, questionnaires and exercise capacity tests.The results of study 1 shown that, obese subjects had lower weekly moderate-to-vigorous physical activity (MVPA) and SF-36 scores, maximal workload and peak oxygen consumption (VO2peak) relative to body weight, but similar absolute VO2peak. Bariatric surgery resulted in -22% body weight,vi- 34% fat mass, -40% visceral adipose tissue and -12% lean mass (LM) changes. Absolute handgrip, quadriceps or respiratory muscle strength remained unaffected but accompanied by an increase in MVPA, SF-36 scores and quadriceps strength relative to LM. No changes in absolute VO2peak were observed after surgery but the ventilatory threshold was decreased.The results of study 2 shown that, obese subject had lower resting lung diffusion capacity with mainly a reduction in pulmonary capillary blood volume and alveolar volume (VA). After bariatric surgery, lung diffusion capacity for nitric oxide, VA and membrane diffusion capacity have improved to varying degrees.The results of study 3 shown that, there was no difference in pulmonary circulation at rest between the two groups, but the pulmonary vascular resistance index (PVRi) was higher with lower heart rate, cardiac output, cardiac index (CI) and mean pulmonary arterial pressure (mPAP) in obese subjects at peak exercise. After being normalized by CI at a common maximum exercise level, the PVRi was still higher, but the difference of mPAP disappeared and manifested a higher mPAP and mPAP/CI slope. The tricuspid annular plane systolic excursion /systolic PAP was lower at rest and at a common maximum exercise level when normalized by CI.In summary, obesity was associated to low vigorous daily physical activity levels, SF-36 physical and mental component scores, higher muscle mass but lower strength/LM ratio and aerobic capacity. Lower spirometry and lung diffusion capacity with mainly reduction in Vc and VA may also limit maximum aerobic exercise capacity. At rest, the pulmonary hemodynamic is preserved, but with a weakness of right ventricular-arterial coupling. At exercise, obesity has a modest, but observable impact on the pulmonary circulation and right ventricular adaptation at exercise, with unexhausted chronotropic reserve and normal chemo-sensibility.Bariatric surgery shows beneficial effects on fat mass loss, metabolic parameters, daily physical activities, SF-36 scores, lung function and stimulated the chronotropic response. However, aerobic capacity is not improved and is associated with a reduced LM and ventilatory threshold potentially triggering hyperventilation. / Doctorat en Sciences de la motricité / info:eu-repo/semantics/nonPublished
| Identifer | oai:union.ndltd.org:ulb.ac.be/oai:dipot.ulb.ac.be:2013/332454 |
| Date | 06 October 2021 |
| Creators | Zhou, Na |
| Contributors | Faoro, Vitalie, Klass, Malgorzata, Moraine, Vincent, Closset, Jean, Iliou, Marie-Christine, Deliens, Tom Prfesseur |
| Publisher | Universite Libre de Bruxelles, Université libre de Bruxelles, Faculté des Sciences de la Motricité, Bruxelles |
| Source Sets | Université libre de Bruxelles |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:ulb-repo/semantics/doctoralThesis, info:ulb-repo/semantics/openurl/vlink-dissertation |
| Format | 3 full-text file(s): application/pdf | application/pdf | application/pdf |
| Rights | 3 full-text file(s): info:eu-repo/semantics/restrictedAccess | info:eu-repo/semantics/closedAccess | info:eu-repo/semantics/closedAccess |
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