Autonomic Function Responses Comparing Cold Pressor and Tilt Table Testing in a Healthy, Normotensive Population

The autonomic nervous system regulates unconscious body functions, such as blood pressure, heart rate, respiration, and thermoregulation. Testing for autonomic dysfunction can be dangerous or costly, though it is crucial for individual wellbeing and for certain diagnoses. Understanding how autonomic clinical testing works, and what correlations exist between different tests, may help make autonomic testing less invasive or dangerous. Therefore, the purpose of this study was to use head-up tilt testing, and cold pressor testing to evaluate autonomic function testing result differences in a young and middle-aged population. Ten total subjects, four males, and six females between the ages of 23 and 45 participated in a ten minute cold pressor test at 10±1°C tap water for ten minutes of submersion and a tilt table test with a five minute tilt at 80°. Vagal tone was measured and heart rate variability was interpreted using frequency data. While many results were insignificant, a more substantial drop was observed between the decrease in total power during the tilt table, than in the cold pressor test. These results indicate that the cold pressor test could serve as a safe pre-screening test before tilt table testing.