Fielding Jeremy, Brantley Lucy, Seigler Nichole, McKie Katie T, Davison Gareth W, Harris Ryan A
Division of Clinical Translational Science, Georgia Prevention Institute, Department of Pediatrics, Georgia Regents University, Augusta, 30912, Georgia.
Pediatric Pulmonology, Georgia Regents University, Augusta, 30912, Georgia.
Pediatr Pulmonol. 2015 Jul;50(7):647-54. doi: 10.1002/ppul.23189. Epub 2015 Apr 2.
Exercise capacity, an objective measure of exercise intolerance, is known to predict quality of life and mortality in cystic fibrosis (CF). The mechanisms for exercise intolerance in patients with cystic fibrosis (CF), however, have yet to be fully elucidated. Accordingly, this study sought to investigate oxygen uptake kinetics and the impact of fat-free mass (FFM) on exercise capacity in young patients with CF. 16 young patients with CF (age 13 ± 4 years; 10 female) and 15 matched controls (age 14 ± 3 years; nine female) participated. Pulmonary function and a maximal exercise test on a cycle ergometer using the Godfrey protocol were performed. Exercise capacity (VO2 peak), VO2 response time (VO2 RT), and functional VO2 gain (ΔVO2 /ΔWR) were all determined. Lung function was the only demographic parameter significantly lower (P < 0.05) in CF compared to controls. Exercise capacity was lower in CF (P < 0.014) only when VO2 peak was normalized for FFM (43.5 ± 7.7 vs. 50.6 ± 7.4 ml/kg-FFM/min) or expressed as % predicted (70.1 ± 14.3 vs. 85.4 ± 16.0%). The VO2 RT was slower (36.1 ± 15.1 vs. 25.0 ± 12.4 sec; P = 0.03) and the ΔVO2 /ΔWR slope was lower (8.4 ± 3 ml/min/watt vs. 10.1 ± 1.4 ml/min/watt; P = 0.02) in patients compared to controls, respectively. In conclusion, a delayed VO2 response time coupled with the lower functional VO2 gain (ΔVO2 /ΔWR) suggest that young patients with CF have impairment in oxygen transport and oxygen utilization by the muscles. These data in addition to differences in VO2 peak normalized for FFM provide some insight that muscle mass and muscle metabolism contribute to exercise intolerance in CF.
运动能力是运动不耐受的客观指标，已知可预测囊性纤维化（CF）患者的生活质量和死亡率。然而，囊性纤维化（CF）患者运动不耐受的机制尚未完全阐明。因此，本研究旨在调查年轻CF患者的摄氧动力学以及去脂体重（FFM）对运动能力的影响。16名年轻CF患者（年龄13±4岁；10名女性）和15名匹配的对照组（年龄14±3岁；9名女性）参与了研究。进行了肺功能检查以及使用戈弗雷方案在自行车测力计上进行的最大运动测试。测定了运动能力（最大摄氧量峰值）、摄氧量反应时间（VO2 RT）和功能性摄氧量增加（ΔVO2 /ΔWR）。与对照组相比，CF患者的肺功能是唯一显著降低（P<0.05）的人口统计学参数。仅当最大摄氧量峰值以去脂体重进行标准化（43.5±7.7 vs. 50.6±7.4 ml/kg-FFM/分钟）或以预测值的百分比表示时（70.1±14.3 vs. 85.4±16.0%），CF患者的运动能力较低（P<0.014）。与对照组相比，患者的VO2 RT较慢（36.1±15.1 vs. 25.0±12.4秒；P = 0.03），ΔVO2 /ΔWR斜率较低（8.4±3 ml/分钟/瓦特 vs. 10.1±1.4 ml/分钟/瓦特；P = 0.02）。总之，摄氧量反应时间延迟以及功能性摄氧量增加（ΔVO2 /ΔWR）较低表明，年轻CF患者存在肌肉氧运输和氧利用受损的情况。除了以去脂体重标准化的最大摄氧量峰值差异外，这些数据还提供了一些见解，即肌肉质量和肌肉代谢导致CF患者运动不耐受。
