Comparison of Treadmill and Bicycle Ergometry in Cardiopulmonary Exercise Testing in an Active Duty Military Population

Background: Cardiopulmonary exercise testing has been advocated to be helpful in the evaluation of exercise tolerance and discerning causes of dyspnea set forth by the 2003 ATS/ACCP consensus statement. VO 2 max is the most accurate estimation of functional capacity, providing an assessment of overall cardiovascular health. Common modalities for exercise testing include the treadmill and bicycle ergometer. The modality of choice is usually determined by the functional or health limitations of the patient. The question is whether the treadmill or bicycle ergometer is the best modality for evaluating a healthy, non-smoking, active military population who exercise on a regular basis. Methods: This is a specific aim of an IRB approved study: Determination of Reference Values for Cardiopulmonary Exercise Testing (CPET) in an Active Duty Population. The target of the cross-sectional study consists of active duty service members between the ages of 20 and 40 with no known history of cardiopulmonary disease who exercise on a weekly basis and are willing to perform two exercise tests. After informed consent is obtained, eligible participants are interviewed to ensure no past medical history of pulmonary or cardiac disease and perform and EKG, CXR and baseline spirometry. On the first session participants complete a maximal exercise test on a treadmill using a Bruce incremental protocol. The second testing session uses a braked cycle ergometer. Participants exercise for both sessions until exhaustion or symptom limited. Data analysis was performed to derive differences in measured VO 2 max in relation to the respiratory exchange ratio (RE) and attainment for ventilatory anaerobic threshold (VAT). Results: 80 subjects (58 males, 22 females) with an average age of 29 y and an average BMI of 25.1 were evaluated on both the treadmill and bicycle ergometer. The basic statistical data is as follows: See Table Conclusions: Basic data analysis on the comparison between to treadmill and bicycle ergometer for cardiopulmonary exercise testing suggests that, given very similar respiratory exchange ratio on both modalities, participants attained a higher VO 2 Max while reaching anaerobic threshold within a shorter time. These results suggest either test may be used in the evaluation of this population despite running as their most common type of exercise. Disclosures: None.