Effect of Mental Activity on Heart Rate, Heart Rate Variability and Respiratory Rate in Healthy Volunteers

Introduction: The link between mental stress and cardiac autonomic regulation plays a significant role in the patho physiological process of cardio neural feedback loop. This study assessed the effect of mental arithmetic and silent reading on heart rate variability, heart rate and respiratory rate in young healthy volunteers.

Materials and Methods: R-R intervals were recorded for five minutes in ten healthy volunteers aged 22-24 years of either sex while resting, doing mental arithmetic, and silent reading in a sitting position. Time and frequency domain approaches were used to measure heart rate variability (HRV). In them, heart rate and respiratory rate were also calculated. Using the paired ‘t' test, mean differences in values were evaluated between resting and mental arithmetic; resting and quiet reading conditions.

Results: Heart rate and respiratory rate were significantly higher during mental arithmetic (p = 0.012, p<0.0001 respectively) and silent reading compared to resting state (p=0.005, p=0.0002 respectively). There was no significant change in HRV during mental arithmetic and silent reading compared to resting state.

Conclusion: Mental arithmetic and silent reading primarily evoke a rise in respiratory rate and heart rate.