Exploring the changes in fluid characteristics of saliva and ocular fatigue due to schoolbag carriage in children of West Bengal

Abstract: BACKGROUND: Energy expenditure for schoolbag carriage culminates in fatigue. It manifests in entire body causing alterations in ocular muscle fatigue levels and fluid characteristics of saliva, such as density, flow rate, and total protein concentration (TPC) of the saliva. Vision and salivary characteristics are predominantly related to performance efficacy. Hence, alterations in ocular muscles and salivary fluid characteristics must be studied for the physical activity of schoolbag carriage. MATERIALS AND METHODS: Twelve healthy school-going males (10–15 years) were randomly taken for the study. They walked for 20 min on a flat surface, at a pace preferred by them, with varying schoolbag loads (0%, 4%, 8%, 12%, and 16% of their body weight). Total walks contemplated in the study are 51 ( n = 51). Ocular fatigue was observed using critical flicker fusion frequency (CFFF). Saliva fluid characteristics were measured from the saliva samples collected once before and once after every walk. RESULTS: CFFF showed a significant decrease ( P < 0.05) after schoolbag carriage while the saliva density increased significantly ( P < 0.05) after the walks. Flow rate and TPC of saliva also increased after schoolbag carriage. Higher change in saliva density was significantly associated with a lower CFFF after walk ( r = −0.288, P < 0.01). Schoolbag load corresponding to 8% of bodyweight was identified to be the safe limit for children. CONCLUSION: The decrease in ocular alertness after schoolbag carriage demonstrates that fatigability related to schoolbag carriage can affect vision and salivary fluid characteristics. Based on alterations in the aforementioned parameters, the load of schoolbag must be not exceed 8% of bodyweight.