Association of Body Mass Index (BMI) With Breath-Holding Time and Six-Minute Walk Distance in Apparently Healthy...

Body mass index (BMI) is a simple anthropometric index widely used to classify individuals based on weight status. Alterations in BMI may influence respiratory function and exercise capacity. This study aimed to assess the association of BMI with breath-holding time (BHT) and six-minute walk distance (6MWD) in apparently healthy adults.

A cross-sectional observational study was conducted in the Department of Physiology, King George's Medical University, Lucknow, after obtaining Institutional Ethics Committee approval. A total of 151 apparently healthy adults aged 20-40 years were recruited and categorized as normal (n=58), overweight (n=85), or obese (n=7) based on WHO BMI criteria. BHT was measured using standard inspiratory breath-hold methodology with nose clips, repeated thrice with a 10-minute interval, and averaged. The 6MWD was assessed on a 30-meter plain ground track marked at 1-meter intervals. Data were analyzed using one-way ANOVA.

Mean BHT was highest in the normal BMI group (44.29 ± 12.22 sec), slightly lower in the overweight group (43.68 ± 7.56 sec), and lowest in the obese group (32.43 ± 10.08 sec), with a statistically significant difference (F=4.709, p=0.010). Mean 6MWD was 608.17 ± 77.95 meters in the normal group, 588.31 ± 74.72 meters in the overweight group, and 542.86 ± 81.23 meters in the obese group. The difference in 6MWD was not statistically significant (F=2.829, p=0.062).

Higher BMI, particularly obesity, is associated with reduced BHT and a trend towards lower 6MWD, suggesting compromised respiratory endurance and functional exercise capacity even in apparently healthy adults.