Free dive to 55 feet? No sweat. It's the return trip that could kill you.
My heart begins pounding the theme from Jaws, triple tempo, as the shipwreck inches into view. Given the task I face—kicking down 55 feet on a single breath—such anxiety is a perfectly normal response, although precisely the wrong one for a free diver. Fear releases adrenaline, which jacks up the heart rate, constricts blood vessels, and causes rapid, shallow breathing. But if I can relax, an entirely different experience awaits: The exhilaration of probing the deep blue unencumbered by air tanks.