Normative Values of Cardiopulmonary Exercise Testing in Healthy but Untrained Volunteers at a Tertiary Care Rehabilitation Center in Pakistan –A Pilot Study

Abstract

Objective: Cardiopulmonary exercise testing (CPET) gives an evaluation of the exercise responses including the cardio-pulmonary, musculoskeletal, hematopoietic, and neuropsychological system. To establish normative reference data for the Cardiopulmonary Exercise Test in a healthy, untrained Pakistani population. Methodology: A cross-sectional study was conducted on 111 healthy untrained volunteers at AFIRM Rawalpindi, from May 2019 to February 2020. They were divided into 4 groups according to age decades (20 to 29, 30 to 39, 40 to 49, 50 to 59). They performed spirometry and cardiopulmonary exercise testing on a treadmill ergometer using Bruce protocol on the cortex, using metalyzer-3B as a gas analyzer. They were assessed for a maximum volume of oxygen utilization, Respiratory Exchange Ratio, Heart Rate, Work Rate, Force Vital Capacity, and Tiffeneau-Pinelli index. Standard values from the United States studies for cardiac and pulmonary functions were compared for reference. Results: All the participants were men between the ages of 20 and 59 years. The maximum oxygen uptake (VO2max) was calculated and found to be highest in the first group (33.7 ± 6.6 mL O₂/kg/min), then in a descending fashion in the other age groups: 30.4 ± 6.0 mL O₂/kg/min, 29.7 ± 7.5 mL O₂/kg/min, and 24.6 ± 3.8 mL O₂/kg/min, respectively. The mean ± SD for HRmax obtained at age 20–29 was 187±16.7, at age 30-39 was 175.9±20.9, at age 40-49 was 183.9±9.5, and at age 50-59 was 178.6±5.8. Work rate and age had an inverse relationship. The Tiffeneau-Pinelli index and Force Vital Capacity were at the lower side of the normal range. Conclusion: Our study revealed significant differences between our values and age-matched U.S. standards using both the Cardiopulmonary Exercise Test and work rate-based estimation formula. Maximal oxygen uptake response was lower, while maximum heart rate and Tiffeneau-Pinelli index were similar. Maximal oxygen uptake and work rate inversely correlated with age.