I'm Worried...

Steve and I have exercised pretty much our entire married life. Which btw is now 18 years (I actually had to use my computer calculator to make sure) BUT..we have never really incorporated running into our workouts. I mean, only the crazies enjoy running. I've always felt like it was a form of body torture. My feet, hips, knees, back, heart and lungs seemed to hurt after every attempt. A few years ago our stake challenged everyone to run in a 5K they were hosting. Steve and I decided we could make the effort, train for 12 weeks (I know you runners are laughing) and join this run. We did it. I felt good about it. Didn't run again for over a year. Fast forward....Saturday's are the day we get to workout together. We had been walking, then walking with weights, then walk/jogging, and finally progressed to jogging the complete 3 mile loop. As we started jogging it wasn't taking us long enough-so..we added a little to the route and bumped it up to a 4.2 mile loop. After sometime of doing this we started getting this CRAZY itch to see how much we could do--and still be somewhat comfortable. We bumped it up to 5 miles. That's when Steve started to scare me. He began talking about his runs, looking forward to the next run. He even started running on his weight days!! What the...This morning he came home from his workout and said 7.5 miles baby! " This 50 year old man can run 7.5 miles." What is happening...he swears he's not going to go marathon crazy on me...but I'm starting to get nervous...