I lost over 50 lbs when I first started training in Brazilian Jiu-Jitsu a few years ago. I'm back at it now to lose some of the weight I gained back. And that made me think of this story...
I was a new guy in the gym and that meant getting beat up a lost and gassing out almost instantly. Seriously, the first day I rolled for real I thought I was going to pass out after 20 seconds. But I kept going.
The next week I could make it like a minute of going hard each time before I would gas out and just get choked/arm barred or whatever. I apologized to this guy I was fighting and said something along the lines "I'm just so out of shape."
His response was totally simple and amazing and I've never forgotten it: "Whatever man, you're here and that's what it takes."
Keeping that in mind as I get back into shape again.