Level of alpha amylase activity in human saliva as a non-invasive biochemical marker of sleep deprivation

Abstract

To investigate the usefulness of the enzyme salivary alpha amylase as a biochemical marker of sleep deprivation in human subjects. Total 168 healthy school-going adolescents studying in 9th grade were selected randomly from morning shift (n = 84) and dayshift (n = 84) schools. The study was undertaken longitudinally for a period of 2 years. Study encompassed administration of questionnaire and collection of saliva samples from the participants. Activity of salivary alpha amylase (sAA) activity was estimated spectrophotometrically and statistical analysis was performed to determine the association between sAA activity and sleep duration. Excessive daytime sleepiness among students was also studied in association with sAA activity. sAA activity of students was found to have a negative correlation with the duration of sleep and a positive correlation with their level of sleepiness. Morning shift students were found to have significantly less sleep and correspondingly higher sAA activity as compared to dayshift students. A significant increase in the sAA activity was noticed in the second year as the students progressed from 9th to 10th grade. Higher amylase activity was also observed in sleep deprived students suffering from excessive daytime sleepiness irrespective of school timings. Salivary alpha amylase activity increases in saliva in response to sleep deprivation. School timings may modulate sleep duration of students. Present finding reveals that sAA could be an appropriate non-invasive biochemical marker for the objective assessment of sleep deprivation among individuals as well as at population level.