Saliva can predict your grades

This article talked about how the pH in saliva can be a biomarker of stress for exams and therefore can also predict how well students do on these exams. As we have learned, saliva is something that’s regulated by the sympathetic and parasympathetic nervous systems. Depending on the situation and whether under stressful conditions the production of it differs. Stressful situations activate the Hypothalamic-pituitary-adrenocortical (HPA) axis and the sympathetic nervous system and therefore resulting in the excess release of stress hormones. These stress hormones, like cortisol, lead to disruptions in normal bodily functions and the effects can be measured as stress response biomarkers. The use of saliva as a biomarker of stress has been used more in recent years due to the easiness of being able to collect samples. More recently the pH level in saliva has also been suggested to be a possible biomarker indicating psychological stress levels. There’s a lower rate of secretion of saliva under stress and therefore a decrease in oral pH. They hypothesized that levels of threat appraisal, experienced stress and test anxiety will be lower post exam than at exam time and challenge appraisal and pH levels will be higher post exam compared to exam time. They also hypothesized that at both times, threat appraisal, experienced stress and test anxiety scores would be negatively associated with pH levels, challenge appraisal would be positively associated with pH levels, and experienced stress and test anxiety would mediate the effect of threat appraisals on pH. They also hypothesized that pH levels would be negatively associated with exam performance and will predict performance on the exam. They studied a total of 121 nursing students that did final exams in microbiology and pharmacology. They collected saliva prior to the exams and tested the pH. They measured challenge and threat appraisals, test anxiety, and experienced stress using scales. Exam performance was measured by the exam grades. Some parts of their hypothesis were supported while others were not confirmed. They found that the higher the pH before the exam, the higher the exam grades and pH significantly predicted exam performance. Overall, they found that their study supports other recent studies that show that there is a dose-response relation between experienced stress and pH. So the higher the stress experienced, the lower the pH. This study provides evidence that pH is a reliable stress biomarker and therefore can be used as a predictor of exam performance.

Reference: Cohen, M., & Khalaila, R. (2014). Saliva pH as a biomarker of exam stress and a predictor of exam performance. Journal of Psychosomatic Research, 77(5), 420–425. https://doi.org/10.1016/j.jpsychores.2014.07.003