Cardiorespiratory Fitness in Middle-aged Men and Women through the Queens College Step Test: A Cross-sectional Study

Abstract

Introduction: Increased Body Mass Index (BMI) is associated with a decreased level of maximium oxygen uptake (VO2max),which indirectly affects Cardiorespiratory Fitness (CRF) in young adults. Therefore, it is important to assess CRF in the middleaged population, despite a high burden of cardiovascular risk factors in this age group. CRF refers to the circulatory system’s ability to supply oxygen to functioning muscles during continuous physical exercise. Maximum oxygen uptake (VO2 max) is the best measure of CRF and serves as the gold standard for quantifying an individual’s aerobic capacity. Aim: To evaluate CRF in middle-aged men and women. Materials and Methods: The present cross-sectional study conducted in the Department of Physiotheraphy, NITTE Institute of Physiotheraphy included a total of 134 subjects aged between 45 and 65 years, who were selected from Justice KS Hegde Charitable Hospital in Mangaluru, Karnataka, India. The male and female groups consisted of 67 subjects each. The study was conducted over a period of 12 months, from March 2022 to March 2023. All subjects were included based on specific inclusion criteria. VO2 max was estimated by following the Queens College Step Test (QCST) method. The Pearson's correlation coefficient was used to examine the relationship between age, height, weight, BMI, waist-to-hip ratio, heart rate, and VO2 max. A p-value <0.05 was considered statistically significant. Results: The mean value of VO2 max was assessed and compared between middle-aged males (65.8±3.5 mL/kg/min) and females (46.6±1.7 mL/kg/min). It was discovered that VO2 max was significantly higher in middle-aged males than in middle-aged females (p<0.001), as indicated by heart rate changes from pretest to post-test. The mean value of BMI was compared between males (24.4±3.2) kg/m2 and females (24.4±4.9) kg/m2 , and the difference was found to be statistically non significant (p-value=0.916). Similarly, the mean value of waist-to-hip ratio was compared between males (0.9±0.1) and females (0.9±0.1), and the difference was also statistically non significant (p-value=0.637). Conclusion: Middle-aged males exhibit substantially higher VO2 max compared to middle-aged females (p<0.001). Consequently, middle-aged females demonstrate a considerable decrease in aerobic capacity, as indicated by VO2 max, and decreased cardiovascular fitness, which serve as predictors of cardiovascular disease risk factors.

Keywords

• aerobic capacity
• cardiovascular fitness
• maximium oxygen uptake
• middle age
• physical activity