Reduction in total lung capacity(TLC) in obese men is associated with restricted expansion of the thoracic cavity at full inflation. We hypothesised that thoracic expansion was reduced by the load imposed by increased total trunk fat volume or its distribution. Using magnetic resonance imaging(MRI) we measured internal and subcutaneous trunk fat and total abdominal and thoracic volumes at full inflation in 14 obese men(mean 52.4yrs, BMI 38.6(range 36-44)kg.m-2 and 7 control men(mean 50.1yrs, BMI 25.0(range 22-27.5)kg.m-2. TLC was measured by multibreath helium dilution and was restricted(<80%pred) in 6 obese men(OR). All measurements were made with subjects supine. Mean total trunk fat volume was 16.65(range 12.6-21.8)L in obese men and 6.98(range 3.0-10.8)L in control men. Anthropometry and mean total trunk fat volumes were similar in OR men and obese men without restriction(ON). Mean total intra-abdominal volume was 9.41L in OR and 11.15L in ON men. In obese men reduced thoracic expansion at full inflation and restriction of TLC were not inversely related to a large volume of a)intra-abdominal or total abdominal fat, b)subcutaneous fat volume around the thorax, or c)total trunk fat volume. In addition trunk fat volumes in obese men were not inversely related to gas volume or estimated intra-thoracic volume at supine functional residual capacity. In conclusion this study failed to support the hypotheses that restriction of TLC or impaired expansion of the thorax at full inflation in middle-aged obese men was simply a consequence of a large abdominal volume or total trunk fat volume or its distribution.
- abdominal volume
- intrathoracic volume
- trunk fat distribution
- Copyright © 2011, Journal of Applied Physiology