Too many musicians neglect exercise. One can speculate why that is: irregular hours, bad eating habits picked up from being on the road or being around bars, and probably other things. And sometimes it's difficult to see the connection between being in shape and pursuing your work/passion. But it's there. If you sleep better, if you have good circulation and good posture, then you'll perform better in all aspects of life. Dave Ferris' story might be inspiring to, say, good runners who are trying to become great runners. But the same story might be intimidating to someone who is struggling just to overcome years of inertia. Like if you're just starting to learn jazz and someone plays a Herbie Hancock cut and says "see, this is the goal. Do this."
I believe the most important thing with exercise is to find something you can do every single day and then do it. Every single day. If it's a part of a daily routine, then you will start to look forward to it, conciously or subconciously, and you'll miss it if it's not there. Make it the organizing principle of your life. That doesn't mean it's the only thing you do or care about. That means it's the one thing you don't sacrifice to anything else. Don't worry about how much you're doing at first. The goal at first should be to shift from inertia to momentum, and to keep some kind of momentum going. From there, you'll eventually find the comfort level. If it's a brisk walk for 30 minutes a day, then that's fine. That's infinitely better than doing nothing at all.
I gets preachy about this stuff. If you read this far, thanks for indulging me.