Changes in lactic acid and plasma glucose levels as a function of examination stress were measured using a 'pinprick' blood sampling method. Blood samples were obtained from 12 subjects at each of four times, one week prior to the exam, within 15 min pre-exam, within 15 min post-exam, and three weeks after the exam.

Glucose was significantly elevated pre-exam over control times and decreased significantly from before to after the exam. Lactic acid was significantly elevated pre-exam over control times and increased significantly before to after the exam. It is suggested that changes in the levels of these metabolites in the blood are indicative of stress levels.

Self-ratings of 'nervousness' were not significantly correlated with either pre-exam glucose or pre-exam lactic acid.

About the Authors

Hall JB, Brown DA. (1979) Plasma glucose and lactic acid alterations in response to a stressful exam. Biol Psychol. 1979 May;8(3):179-88.