. >> reporter: for william halol, stress is a constant fight, the d.c.ollege professor says simply watching the news can make him feel so uncomfortable he has a tough time sleeping. >> well, things can trigger it, like when the chilean miners were trapped underground, it terrified me. my primary care physician said i could take medication or i can learn how to relax. >> reporter: he chose relaxation. but for most people, that's easier said than done. so he saw another doctor, an internist who specializes in integrative medicine, a combination of holistic and western practices. >> we get probably over 50% of our patients come to us with a major stress problem. >> reporter: the doctor suggested halol try a pocket-sized machine that measures heart rate variability. >> i like to call it sixth or sedge vital sienl. it shows the changes in the heart rate, instantaneous changes. there's a healthy pattern and unhealthy patterns. >> reporter: he says heart rate variability measures the autonomic nervous system, the part of our body that reacts to stress and contr