Boston Marathon
Ian Chillag/NPR

Imagine wearing this for 26.2 miles.

Judging by the Flickr sends, Ian Chillag has reached mile six of the Boston Marathon. He's running along with 1968 champ Amby Burfoot. In a Twitter post at 11:18 a.m., Chillag writes:

"Entering Natick. First cowbell heard. Race has begun."

They're aiming for a comfortable pace of just under four hours. Chillag posted a warning sign, from just past mile five: "That slowing down thing? Not happening. We may pay for this..."