For today’s edition of Dear Mark, I’m answer two questions from readers. First, does Bikram yoga qualify as sprinting or high intensity training? It’s certainly intense, and it’ll make you sweat bullets and work hard to the point of nausea, but does it actually accomplish the same training effects as sprinting or intervals? Find out down below. Next, you often hear that body fat is the main repository for environmental toxins. This is true, but does that mean the body “holds on” to body fat to prevent systemic dispersal of the toxins it contains? Can stored toxins make losing body fat harder that it already is?