Abstract 446 Poster Session III, Monday, 5/3 (poster 335)
Studies of heart rate variability in mental stress situations have produced contradictory results: both increases and decreases in parasympathetic and sympathetic tone have been reported. These discrepancies may be due to deficiencies in the mental stress model or to inappropriate choice of control periods. We assessed heart rate variability in a new setting which combines mental stress with mental work in a realistic environment. We recruited 17 pediatric and anesthesia residents who underwent simulation-based training. Each physician participated in a scenario simulating a medical emergency in their respective fields. They were all monitored with continuous ambulatory ECG. The ECG's were analyzed for absolute heart rate and heart rate variability in both temporal and spectral domains of 5 minute epochs. The epochs containing: 1) baseline lowest heart rate (minHR), 2) quiet standing (Standing) and 3) peak stress state (Stress) were compared using a repeat measure ANOVA for each subject. Standing and min HR were both measured to take into account change in body position with Stress. Spectral analysis was measured in normalized units to minimize effect of changes in total power. Results: Heart rate significantly increased during mental stress (minHR 67±10, Standing 79±13, Stress 102±12, p≤0.05). No significant changes were seen with temporal heart rate variability analysis among the three states. Power spectral analysis revealed a significant increase in low frequency power, a marker of sympathetic activity and a concomitant decrease in high frequency power, a measurement of vagal activity, during Stress (78 ± 11%, 22 ± 11%, LF%, HF%), as compared to minHR (61 ± 16%, 39 ± 16%, LF%, HF%), or Standing (68 ± 11%, 32 ± 11%, LF%, HF%, p≤0.05). LF/HF ratio, used to reflect sympathetic modulations, revealed a significant increase with Stress but no significant change between min HR and Standing (1.93 ± 1.05, 2.61 ± 1.4, 5.14 ± 3.5, minHR, Standing, Stress, p=≤0.05). Conclusions: Using an appropriate model, mental stress is seen to increase sympathetic activity as evidenced by an increase in low frequency power. It also results in a diminution of vagal activity as seen by the decrease in high frequency power. Heart rate variability is a useful tool in assessing adequacy of training scenarios.
(Spon by: Daniel Bernstein)
About this article
Cite this article
Kaegi, D., Halamek, L., Van Hare, G. et al. Effect of Mental Stress on Heart Rate Variability: Validation of Simulated Operating and Delivery Room Training Modules. Pediatr Res 45, 77 (1999). https://doi.org/10.1203/00006450-199904020-00463
Teachers’ experienced classroom demands and autonomic stress reactions: results of a pilot study and implications for process-oriented research in vocational education and training
Empirical Research in Vocational Education and Training (2021)