I learned that I suffer from anxiety when, some 13 years ago at the age of 20, I checked myself into a hospital for what I was convinced was an impending heart attack . My chest felt tight, my breathing was rapid , head spinning, arms tingling. I couldn’t think straight. After a series of tests, the ER doctor told me that physically, I was healthy. Then he gently suggested a diagnosis: what I’d just experienced may have been a panic attack .

That a mental state could manifest itself as physical symptoms was a complete revelation to me. I’d experienced a variety of them before (usually attributing them to post-illness recovery or environmental reactions) but not at this magnitude. To help treat my anxiety, among other things, he recommended aerobic exercise.…