The worst part about starting exercise after a couple of years not doing any..was my inability to go for very long. I lacked endurance and stamina. I still am not where I want to be when it comes to both. And while you may think they are the same they are not..at least not to me anyways. When I think endurance I think of the ability to push through things, especially pain, and finishing what you start. When I think stamina I think of the ability to go harder for longer. But some people categorize them as one and the same.
When I went to the gym for the first time, at 220+ pounds, I could only walk on the treadmill for 12 minutes before the shin splints got so unbearable I thought I was going to break my leg. That is to be expected for someone that is obese. You muscles, bones, ligaments, tendons, everything that makes you move is under a tremendous amount of pressure. Their way of fighting back is to cause pain and make you stop. But you have to endure and push yourself to go further. Every time I went back to the gym I made myself, regardless of how much I wanted to stop, or how much it hurt, walk a little further on that blasted treadmill. Today I can run for 20 minutes straight at a 5-7 mph pace on a 2%incline, but as far as walking...that I can do for 60-100 minutes on a 10% at a 3.5-3.8 mph pace! Imagine after only 11 months, I have improved that much. And even still today I challenge myself to go to further lengths. I couldn't run for more than 15 seconds less than 4 months ago, and I completed my first 5k in 38:17! I slowed down long enough to catch my breath, but kept going.
Building that ability to keep going is where my stamina comes into play. By training my body to last longer I can push myself in more demanding sports. I have a goal to run a half marathon by May of 2013. The only way I will be able to do that is to challenge my ability to run for longer distances. While a 5k might seem like a lot now, I plan on it looking like an inch worm in a few weeks. On Monday I did 5.5 miles in 55 minutes on an 8% incline. Had I done it on say a 2% incline, it would have taken less time. A half marathon is just over 11 miles. If I am at 5.5 now, I will be at 11 in no time. It is all about your mental as well as physical ability to challenge your body. If you don't challenge it you will never know what it is capable of.
So don't sit there and let the idea of exercise intimidate you, you are only hurting yourself if you don't do it. Start small, walk from your house to the mail box as fast as you can, and build your endurance. Then when you feel like you can endure the pain a little longer, go for it. I know if I can do it so can you, the only person holding you back from your fitness goals is you!