Gender Gap in Stress: Differences Amongst Sex in Biomarkers of Stress and Anxiety.

Past research has shown that females have lower biomarkers of stress compared to males. Further, when exposed to acute stressors, females have also been shown to demonstrate reduced stress biomarker responses compared to males. However, this difference has not been explored with respect to different types of stress (i.e., physical vs mental and combined physical and mental stress). PURPOSE: To examine male and female (sex) differences in biomarkers of stress and anxiety, following the exposure of physical stress (exercise) and concurrent mental and physical stress. METHODS: This study was a randomized controlled study. Subjects (n=54; 29 males & 25 females) were randomly assigned to either exercise alone (EA) or a concurrent stress challenge (CSC). In the EA group, participants performed a Ruffier Squat test (30 squats in 45 seconds), while the CSC group of participants performed the exercise protocol along with a virtual reality simulated active shooter drill. Measurements of heart rate (HR), state of anxiety inventory (SAI), and a saliva sample were organized four times throughout the study, 1) 30 minutes prior to the exercise testing 2) 5 minutes prior to exercise 3) 5 minutes post testing 4) 30 minutes post testing. Saliva samples were given to examine concentrations of 2 biomarkers: Secretory Immunoglobin-A (SIgA) and Salivary Alpha Amylase (sAA). RESULTS: With respect to sAA, females demonstrated significantly lower concentrations in the EA condition compared to males (p < 0.01). Both males and females experienced a significant increase in sAA from pre to post stress (p < 0.01). With respect to SIgA, females demonstrated significantly lower concentrations immediately post stress compared to males. In regard to SAI, mean SAI values were significantly elevated immediately post stress, with no differences between groups or conditions. Finally, with respect to HR, mean HR values were significantly higher immediately post stress compared to all other timepoints and males demonstrated significantly lower HR in the EA condition compared to females. CONCLUSION: This study found significant differences in markers of stress between male and females showing different concentrations of SIgA and sAA in different stress groups as compared to men, with women having significantly lower concentrations of sAA and SIgA in both groups post stress. Though men did have a lower HR response, this could be due to the factors of intensity differences like muscle mass or conditioning between the groups. These findings further support past research demonstrating females elicit a reduced stress biomarker response to acute stress. Additional research is needed to address any underlying mechanisms as to what drives the gender differences during acute stress.