Related Experiment Video
Updated: Jun 4, 2026

Investigation into Deep Breathing through Measurement of Ventilatory Parameters and Observation of Breathing Patterns
Published on: September 16, 2019
Weight loss via diet and exercise improves exercise breathing mechanics in obese men
Tony G Babb1, Brenda L Wyrick1, Paul J Chase1
1Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and the University of Texas Southwestern Medical Center, Dallas, TX.
Background:
Obesity alters breathing mechanics during exercise. Weight loss improves lung function at rest, but the effect of weight loss, especially regional fat loss, on exercise breathing mechanics is unclear. We hypothesized that weight loss, especially a decrease in abdominal fat, would improve breathing mechanics during exercise because of an increase in end-expiratory lung volume (EELV).
Methods:
Nine obese men were studied before and after weight loss (13% ± 8% of total fat weight, mean ± SD). Subjects underwent pulmonary function testing, underwater weighing, fat distribution estimates (MRI), and graded cycle ergometry before and after a 12-week diet and exercise program. In seven men, esophageal and gastric pressures were measured. The effects of weight loss were analyzed at rest, at ventilatory threshold (VTh), and during peak exercise by dependent Student t test, and the relationship among variables was determined by correlation analysis.
Results:
Subjects lost 7.4 ± 4.2 kg of body weight (P < .001), but the distribution of fat remained unchanged. After weight loss, lung volume subdivisions at rest were increased (P < .05) and were moderately associated (P < .05) with changes in chest, waist, and hip circumferences. At VTh, EELV increased, and gastric pressure decreased significantly (P < .05). The changes in waist circumference, hip circumference, BMI, and sum of chest, waist, and hip circumferences were also consistently and significantly correlated (P < .05) with changes in gastric pressure during exercise at VTh.
Conclusions:
Modest weight loss improves breathing mechanics during submaximal exercise in otherwise healthy obese men, which is clinically encouraging. Improvement appears to be related to the cumulative loss of chest wall fat.
Related Concept Videos
COPD: Management Using Bronchodilators and Corticosteroids
Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be met...
Mechanism of Breathing III: The Accessory Muscles
The respiratory system is a complex network that relies on primary respiratory muscles like the diaphragm, but also involves accessory muscles to enhance lung expansion and airflow during both inhalation and exhalation.
Enhancing Inhalation with Accessory Muscles:
Accessory muscles such as the sternocleidomastoid, scalene, intercostal, and abdominal muscles are crucial when additional respiratory effort is required, such as during deep...
Drug Dosing: Obese Patients
Pharmacokinetics in Obese Patients: Drug Absorption and Distribution

