Elevation and Lung Volume Abstract

 

Gabby Godklang, Colton Jackson, Whitney Grant-Seach

 

CU Boulder, Fall 2007

                                   

In our lab, “Lung Volume and Capacity: A Comparison of High and Low Elevations”, we ran tests to determine if the elevation at which an individual grew up in has an effect on his/her lung volume.  Studies have shown that people who have grown up at higher elevations have higher lung volume capacity than those that have been raised at lower elevation.  Our question was if this could be observed in individuals at CU.  Lung capacities are larger at higher altitudes because there is less pressure from the atmosphere (therefore having lower oxygen levels).  We hypothesized that because oxygen levels are lower at higher elevations, a person’s background elevation will affect the lung volume of the individual.

            To test our hypothesis we used a digital spirometer to estimate various lung volumes by inhaling and exhaling.  We measured five volumes: tidal volume, the amount of air expelled during normal breathing, vital capacity, the total quantity of air that can be exhaled following deep inhalation, expiratory reserve volume, the quantity of air that is forcibly exhaled after normal exhalation, and inspiratory reserve volume, the amount of air that can be forcibly inhaled after normal inhalation.  Lastly, we standardized residual volume, the minimum quantity of air that is in the lungs all of the time, at 1.5 L. Subjects were directed to breathe normally into the mouthpiece with their noses held shut. We tested the lung volumes of eight people, four who grew up in elevations less than 3,000 feet and four who grew up in elevations more than 3,000 feet.  The maximum elevation we tested was 6,100 feet and the minimum elevation was 800 feet.  We predicted that the subjects from higher elevations would have a higher lung volume than subjects from lower elevations. 

            While the majority of our results were not significant. The p values for each measurement: 0.230, 0.120, 0.334, and 0.388, tidal volume (p=.007) showed a significant difference between groups.  Some variables that could have affected the test, but were not factored in include: sex, height, amount of exercise, and if the subject smoked or not.  There were no similar student studies on the CABLE web page, but we found a study composed by researchers of the American Journal of Human Biology that provided evidence that people who grow up at higher elevations have greater lung volumes than those who grow up at lower elevations and supported our hypothesis.  This study compared individuals from La Paz, Bolivia (elevation 3,750 meters) to individuals from coastal regions of Bolivia (sea level). However, we concluded that there are likely many factors besides elevation that affect lung volume.  If we were to run another experiment we would be more specific in our testing groups (sex, height, smoking, athleticism), obtain a much larger testing group to average out these factors, and choose subjects that grew up with a greater difference in elevation.