Nathan Faes and Pam Geier
In this experiment we tested lung volume and flow rates of both in-shape and out-of-shape men to find out who has the greatest lung capacity. Lung capacity should increase with fitness and muscle mass, as the body requires more oxygen. Based on this prediction, we hypothesize that the lung capacity of in-shape males will be greater than the lung capacity of out-of-shape males.
This hypothesis was tested using 6 male subjects between the ages of 19 and 25. Three subjects were “in-shape”. “In-shape” is defined as an individual who exercises at least 4 times / week for a minimum of ½ hour / session. The 3 remaining test subjects were defined as “out-of-shape” with no formal workout régime. Participants ran throughout the University of Colorado’s Norlin quad for 7 minutes after which their lung capacity was measured using a spirometer. Test subjects were then asked to rest for 10 minutes after which their lung capacity was measured for a “resting” rate.
The prediction that healthy, in-shape lungs will hold more air than out-of-shape lungs ranks lung capacity from greatest volume to lowest volume as follows: In shape men resting, In shape men after run, Out of shape men resting, Out of shape men after run.
Test results contradict our hypothesis as follows: Average lung volume (in Liters) for resting men - in-shape are 4.775 L, out-of-shape are 5.594 L. With density factored in and after the run – in-shape are 72.84 L, out-of-shape are 73.07 L. Average flow rates (L/s) after the run – in-shape are –1.347 L/s, out-of-shape are –1.48 L/s.
The R2 value of average lung volume in liters is 0.7079. This indicates that 70 percent of the variability in lung capacity is explained by subjects being in-shape vs. out-of-shape. Average flow rates have an R2 value of 0.5726 L while average lung volumes based on density reflect an R2 value of 0.5287 L/s.
Of note, subjects were having trouble blowing into the spirometer in a proper manner. With this complication, experimental data had to be narrowed down to the best test result for each subject in each test. It would be beneficial to have all six test subjects attached to spirometers while on treadmills – walking followed by running at equal rates for equal amounts of time. Continual bio-feedback through the meters would offer a picture into body dynamics as lung capacities are stretched, stressed, and oxygen and energy stores are accessed though different forms of glycolosis.
In an article by Peter Wagner (Medscape Today), the limitations of lung capacity are discussed. Oxygen transport is dependent on four factors – the lungs, Hb binding, blood flow, and the capillary-mitochondrial diffusion in the muscle. Because all four components are dependant on one another, with the lungs being the limiting factor in maximum oxygen capacity, an individual cannot just simply train the lungs.
Based on data gathered in this experiment along with research by experienced exercise physiologists, a revision to our hypothesis is required. “The lung capacity of in-shape males will be greater than the lung capacity of out-of-shape males” should read: The support systems surrounding the lungs of in-shape males will be greater than the support systems of out-of-shape males.
Wagner, P. 2005. Why Doesn’t Exercise Grow the lungs When Other Factors Do? Exercise and Sport Sciences Reviews, 33(1):3-8, 2004, www.Medscape.com.
Jones MD, N et. al., 2000, Exercise Limitation in Health and Disease, N Engl. J Med 303:632, August 31, 2000.
Daussin, F. et. al., 2007, Effect of interval versus continuous training on cardiorespiratory and mitochondrial functions: relationship to aerobic performance improvements in sedentary subjects, Am J Physiol Regul Integr Comp Physiol 295: R264-R272, April 16, 2008