Health Apple Watches Can Predict When You’ll Get Sick, Users Say. Can a Health Tracker Really Do That? But they do collect and analyze metrics that are strongly linked to the autonomic nervous system, which plays a crucial role in regulating various functions in the body, including the immune response, Varun Mishra, PhD, assistant professor at Northeastern University and director of the university’s Ubiquitous Computing for Health and Well-being (UbiWell) Lab, told Health.