Author + information
- Na Zhou1,2,
- Vitalie Faoro1,
- Malgorzata Klass1,
- Patrizia Loi3,
- Jean Closset3,
- Jean Jacques Moraine1,
- Kevin Forton1,
- Gael Deboeck1,4 and
- Michel Lamotte4
The World Health Organization defines obesity as “an abnormal or excessive accumulation of fat that poses a risk to health”. In the general population, high levels of exercise capacity are associated with lower levels of total body fat and higher levels of lean body mass. But it is not clear whether this observation remains true in obesity.
Aim of this research: To evaluate the association between lean body mass, fat mass and exercise capacity in obesity.
36 obese patients without major complications (13 men / 23 women, age: 45.6 ± 14.0 years, height: 168.4 ± 7.9 cm, weight: 104.5 ± 13.4 kg, body mass index (BMI): 36.9 ± 4.1 kg/m2). Body composition were determined by impedancemetry (TANITA) and absorptiometry (dual-energy X-ray absorptiometry (DXA)). Participants will perform an incremental cardiopulmonary exercise test (CPET) on a cyclo-ergometer in order to determine maximal aerobic capacity (VO2max) with breath by breath measurements of oxygen uptake VO2, anaerobic threshold and ventilation (VE) at progressively increased workload (15-20 W/min) until exhaustion. The anaerobic threshold (AT) was determined by the V-slope method.
In obese subjects, the charge at the level of the anaerobic threshold (watt@AT) and the maximum ventilation (VE max) were correlated with the lean mass (r = 0.49, p <0.05; r = 0.31, p <0.05). Maximal oxygen uptake per kilogram (VO2 max/kg) and watt@AT were inversely correlated with the fat mass (r = -0.42, p <0.05; r = -0.30, p <0.05). In addition, the specific VO2max/kg and VE max are associated with the fat / lean ratio (r = -0.43, p <0.05; r =-0.43, p <0.05).
This study shows that why a higher lean mass also makes it possible to raise the level of load of anaerobic threshold where appears dyspnea at the effort. Even in the obese population, a better body composition, with a lower fat mass or an increased lean mass, is associated with a delayed this dyspnea threshold, allows to reach higher VE max levels and to have a better VO2max, so improved their exercise ability.
These observations underscore the importance of diet control and the promotion of physical activity in obese adults in order to improve their quality of life, their ability to exercise and their survival.