Presenting Author Cooper Medical School of Rowan University
Objective. Our study objective is to evaluate whether gender differences in both perceived and biological stress levels will alter resting heart rates.
Hypothesis. We hypothesize that females will experience higher levels of perceived and biological stress which will translate to a higher resting heart rate compared to males.
Methods. 19 first-year medical students participated in this study. Participants wore Fitbits to collect heart rate data throughout the course of the academic year. During exam weeks (the “stressor”), participants filled out a standard psychometric questionnaire to assess perceived stress levels and saliva samples were collected to measure cortisol and alpha-amylase concentrations.
Results. Our study showed that females have higher resting heart rates than males (65.8±6.8 bpm vs 57.7±4.34 bpm, plt;0.001). Females recorded having higher perceived stress levels than males (7.9±4.6 vs. 2.12±5.27, plt;0.001), as well as having higher salivary alpha-amylase concentrations than males (33.95±29.50 U/mL vs. 75.4±76.44 U/mL p=0.001). No difference in salivary cortisol concentrations between females and males are seen (0.44±0.25 ug/dL vs. 0.39±0.24 ug/dL, p= 0.3).
In females, there is a weak positive correlation between RHR and perceived stress level (0.22), as well as with amylase (0.26). In males, there is a moderate negative correlation between RHR and perceived stress level (-0.48) and a weak positive correlation between RHR and cortisol (0.26). There was no relationship between RHR and amylase.
Conclusion. Females have higher levels of perceived stress levels which is in agreement with their higher levels of alpha-amylase, a marker of psychosocial stress via the sympatho-adrenal-medullary system. As salivary alpha-amylase has been suggested to reflect catecholaminergic reactivity, it seems likely that this is responsible for the increased resting heart rate. This relationship is not consistent in males where perceived stress is associated with a decrease in RHR. However, in males a relationship was seen between biological markers of stress (cortisol via the hypothalamic-pituitary-adrenal axis) and RHR. This study suggests that the relationship between biological measures of stress and heart rate vary with gender and that females experience an increased level of perceived stress overall.
