Went to the doctor to have a mole on my back looked at (you'll be glad to know that the exciting I-have-melanoma-and-it's-metastasized! post will not need to be written). Since I hadn't gone in a long time, she ordered some routine blood tests. And that very afternoon I got an email informing me that my test results were in and could be accessed online. How cool is that? Instant gratification and no personal contact required!
My hemoglobin was low, which means my blood's ability to carry oxygen is likewise low. Maybe that explains why a very slow and gentle one-mile jog leaves me gasping and panting for air. You may be theorizing that if I'd jog more than once a month I'd find it easier, but I prefer to blame it on my blood.