Heart Rate Reactivity In Stressed and Sleep Deprived Individuals

Acute sleep deprivation and acute stress lead to similar changes in physiological and cognitive functioning. However, very little research has investigated the combined effects of acute sleep deprivation and acute stress on heart rate reactivity. The first aim of the current study was to compare delta heart rate in acutely sleep deprived and non-sleep deprived participants during an acute psychosocial stressor. It was hypothesized that sleep deprived participants would exhibit lower delta heart rate than well-rested participants. The second aim was to examine heart rate recovery after exposure to an acute stressor. It was hypothesized that sleep deprived individuals would experience delays in heart rate recovery immediately after the stressor. Lastly, an exploratory analysis was run to explore the relationship between cortisol and heart rate reactivity in sleep deprived and non-sleep deprived conditions. A sample of 15 healthy adults was included in the analyses. The participants either spent a night of total sleep deprivation (N=9) or a night of well-rested sleep (N=6). Beats-per-minute recordings were taken before the acute stressor (pre-stress), during the acute stressor (stress), and immediately after the acute stressor (post-stress). Saliva samples were collected at the end of the pre-stress, stress, and post-stress time points. A significant difference was observed in estimated BPM variance between conditions, with sleep deprived individuals having less variability in their heart beats in comparison to non-sleep deprived individuals. There were no significant differences in delta heart rate or heart rate recovery between conditions. Moreover, exploratory analyses did not reveal a significant relationship between cortisol and estimated BPM. Taken together, the results of the present study suggest that acute sleep deprivation lowers estimated BPM variance. Future research should be conducted to better understand the extent to which acute psychosocial stress impacts physiological stress responses, namely heart rate reactivity and variance, in acutely sleep deprived individuals.