The Correlation of Smartphone Screen Time With Resting Respiratory Rate, Head-Neck Alignment, and Chest Expansion Among University Students.

Background and objective Smartphone usage has increased considerably among young adults and is often associated with prolonged neck flexion and forward head posture. Excessive screen time may lead to alterations in head-neck alignment, musculoskeletal adaptations, and changes in respiratory mechanics. Previous studies have suggested that poor posture can influence breathing patterns and respiratory function; however, evidence regarding the relationship between smartphone screen time, head-neck alignment, and resting respiratory rate remains limited. This study aimed to assess the correlation between smartphone screen time, resting respiratory rate, head-neck alignment, and chest expansion among university students. Methodology A cross-sectional observational study was conducted involving 300 university students reporting increased smartphone use. Resting respiratory rate was assessed in a relaxed sitting position. Head-neck alignment was evaluated using the craniovertebral angle (CVA), measured through lateral-view photographic analysis. Pearson's correlation analysis was performed to determine the relationships between smartphone screen time, resting respiratory rate, CVA, and chest expansion measurements. To account for multiple comparisons, a Bonferroni correction was applied, and the adjusted level of statistical significance was set at p < 0.01. Results Correlation analysis demonstrated a very weak negative correlation between smartphone screen time and resting respiratory rate (r = -0.0478, p = 0.4092), which was not statistically significant. A very weak positive correlation was observed between smartphone screen time and CVA (r = 0.1232, p = 0.0329); however, this association did not remain statistically significant after Bonferroni correction. A very weak negative correlation was observed between smartphone screen time and axillary chest expansion (r = -0.1574, p = 0.0063), which remained statistically significant after Bonferroni correction. The associations with fourth intercostal space chest expansion (r = -0.1139, p = 0.0488) and xiphisternal chest expansion (r = -0.0613, p = 0.2902) were not statistically significant after Bonferroni correction. Conclusions Smartphone screen time demonstrated predominantly weak associations with head-neck alignment and chest expansion among university students. After Bonferroni correction for multiple comparisons, only the association with axillary chest expansion remained statistically significant; however, the effect size was weak, indicating limited clinical relevance. No significant association was observed between smartphone screen time and resting respiratory rate, while the association with CVA did not remain significant after correction. Further longitudinal studies with larger sample sizes and adjustment for potential confounding factors are warranted.