Physiological association of the breakpoint with the duration of hyperventilation.

Objectives: To determine the relationship of body mass index (BMI) with breath-holding time (BHT) as well as that of BHT with the duration of hyperventilation (DOH) in young healthy adults.

Methods: An observational study was performed at Shalamar Medical and Dental College, Lahore, Pakistan, between May 2021 and June 2022. Healthy first-year Bachelor of Medicine, Bachelor of Surgery students aged 18-22 years, with a normal BMI were included. Spirometric measurements were taken through a spirometer pod connected to a pneumotachometer (model: Power Lab 26T). Body mass index was calculated as the weight (kg) to height (m) ratio. Pearson correlation, linear regression, and t tests were applied using SPSS.

Results: A total of 101 subjects participated, comprising of 44 men and 57 women. A weak negative association was found between BMI and BHT in all subjects (r= -0.08, =0.34), in men (r= -0.24, =0.11), and in women (r= -0.092, =0.497). Furthermore, a strong association was observed between BHT and DOH in all subjects (r=0.64, =0.000), in men (r=0.604, =0.000), and in women (r=0.518, =0.000). Moreover, a nonsignificant weak inverse linear regression was found between the BMI and BHT of all subjects (β= -0.087, =0.38), of men (β= -0.241, =0.11), and of women (β= -0.092, =0.49). Lastly, a significantly strong positive regression was observed between the BHT and DOH of all subjects (β=0.637, =0.000), of men (β=0.604, =0.000), and of women (β=0.518, =0.000).

Conclusion: No association was found between BMI and BHT. A strong positive association was observed between BHT and DOH in all healthy young people.