Norms of vagal nerve activity, indexed by Heart Rate Variability, in cancer patients.

Recent research has begun to show the role of the activity of the vagus nerve in cancer prognosis. However, it remains unknown whether cancer severity can impair vagal nerve activity. This study combined data (N=657) of five different cancers (colorectal, pancreas, prostate, lung and ovarian) concerning patients' Heart Rate Variability (HRV), a vagal nerve activity index. These data were compared to HRV levels of a healthy sample in another study. In addition, we examined the moderating effects of age, gender and cancer stage on HRV. The mean HRV of the cancer patients sample was significantly lower (HRV=22 ms) compared to the healthy sample (HRV=50 ms) (p<0.000001). While age and gender did not significantly affect HRV, cancer patients with advanced stages had significantly lower HRV than those with early stages (p=0.011). A possible bi-directional relation between cancer and vagal nerve activity is discussed. These findings are of importance for prognostication since they provide researchers and clinicians with expected values of vagal nerve activity in cancer patients.