Mild obesity does not limit change in end-expiratory lung volume during cycling in young women

• Published in: Journal of applied physiology (1985) Vol. 92; no. 6; pp. 2483 - 2490
• Main Authors: Babb, T. G, DeLorey, D. S, Wyrick, B. L, Gardner, P. P
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.06.2002; American Physiological Society
• Subjects: Adult; Airway Resistance; Bicycling - physiology; Biological and medical sciences; Female; Humans; Lung - physiology; Lung Volume Measurements; Medical sciences; Metabolic diseases; Obesity; Obesity - physiopathology; Physical Endurance; Pressure; Respiration; Respiratory Mechanics; Respiratory Physiological Phenomena; Work of Breathing; Physical exercise; Human; Obesity; Nutrition disorder; Bicycle ergometer; Respiratory system; Lung volume; Lung function; Female; Pulmonary ventilation; Expiratory reserve volume; Respiration; Respiratory control; Nutritional status
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00235.2001

Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas and The University of Texas Southwestern Medical Center, Dallas, Texas 77231 To investigate the effects of obesity on the regulation of end-expiratory lung volume (EELV) during exercise we studied nine obese (41 ± 6% body fat and 35 ± 7 yr, mean ± SD) and eight lean (18 ± 3% body fat and 34 ± 4 yr) women. We hypothesized that the simple mass loading of obesity would constrain the decrease in EELV in the supine position and during exercise. All subjects underwent respiratory mechanics measurements in the supine and seated positions, and during graded cycle ergometry to exhaustion. Data were analyzed between groups by independent t -test in the supine and seated postures, and during exercise at ventilatory threshold and peak. Total lung capacity (TLC) was reduced in the obese women ( P  < 0.05). EELV was significantly lower in the obese subjects in the supine (37 ± 6 vs. 45 ± 5% TLC) and seated (45   ± 6 vs. 53 ± 5% TLC) positions and at ventilatory threshold (41   ± 4 vs. 49 ± 5% TLC) ( P  < 0.01). In conclusion, despite reduced resting lung volumes and alterations in respiratory mechanics during exercise, mild obesity in women does not appear to constrain EELV during cycling nor does it limit exercise capacity. Also, these data suggest that other nonmechanical factors also regulate the level of EELV during exercise. ventilation; control of breathing; lung volumes; pulmonary function