Hakala K, Mustajoki P, Aittomäki J, Sovijärvi A
Department of Medicine, Division of Pulmonary Medicine and Clinical Physiology, Helsinki University Hospital, Finland.
Clin Physiol. 1996 May;16(3):229-38. doi: 10.1111/j.1475-097x.1996.tb00571.x.
The aim of this study was to determine the effect of weight loss induced by 6 weeks very-low-calorie-diet (VLCD) and behavioural intervention on pulmonary gas exchange during exercise in non-smoking morbid obese (BMI>40 kg/m2) otherwise healthy patients. Seven obese patients underwent a maximal bicycle ergometer test with continuous analysis of expired air and arterial blood sampling before and after a mean weight loss of 18% (25.7 kg, range: 10-50 kg). Body mass index (BMI) decreased with weight loss from 46.6 (6.3) kg/m2 to 38.0 (4.7) kg/m2 (P<0.01). Oxygen consumption (VO2) at low and submaximal exercise levels decreased after weight reduction, but the change was not statistically significant. The peak oxygen consumption related to body weight (VO2/kg) increased 22% from the initial 16.2 (3.6) ml/min/kg to 19.8 (3.1) ml/min/kg (P<0.05). Decrease in VCO2 was significant at submaximal exercise level. Ventilatory equivalent for CO2 increased significantly after weight reduction (P<0.05). Standing up and light exercise resulted in a significant increase in the mean arterial oxygen tension (PaO2) (P<0.05) and a significant decrease in the mean alveolar-arterial difference P(A-a)O2 (P<0.05) when compared to supine values. The mean increase in PaO2 with weight loss was not significant. The peak P(A-a)O2 decreased significantly after weight reduction. In conclusion, weight reduction induced by VLCD and behavioural intervention without exercise therapy can improve gas exchange during exercise in morbid obesity. Increased wasted ventilation, and a tendency to alveolar hyperventilation, after weight loss may reflect a delay in the adaptation of regulation of breathing to rapid weight loss.
本研究的目的是确定6周极低热量饮食（VLCD）和行为干预引起的体重减轻对不吸烟的病态肥胖（BMI>40 kg/m²）但其他方面健康的患者运动期间肺气体交换的影响。7名肥胖患者在平均体重减轻18%（25.7 kg，范围：10 - 50 kg）前后进行了最大运动强度的自行车测力计测试，同时持续分析呼出气体并采集动脉血样。体重减轻后，体重指数（BMI）从46.6（6.3）kg/m²降至38.0（4.7）kg/m²（P<0.01）。体重减轻后，低强度和次最大运动水平下的耗氧量（VO₂）降低，但变化无统计学意义。与体重相关的峰值耗氧量（VO₂/kg）从最初的16.2（3.6）ml/min/kg增加了22%，至19.8（3.1）ml/min/kg（P<0.05）。在次最大运动水平下，VCO₂的降低具有显著性。体重减轻后，二氧化碳通气当量显著增加（P<0.05）。与仰卧位值相比，站立和轻度运动导致平均动脉血氧分压（PaO₂）显著升高（P<0.05），平均肺泡 - 动脉氧分压差P(A - a)O₂显著降低（P<0.05）。体重减轻导致的PaO₂平均升高无显著性。体重减轻后，峰值P(A - a)O₂显著降低。总之，VLCD和行为干预而非运动疗法引起的体重减轻可改善病态肥胖患者运动期间的气体交换。体重减轻后无效通气增加以及肺泡过度通气的趋势可能反映了呼吸调节适应快速体重减轻的延迟。
