Being in shape for the gym and the real world. Is there a difference?

I tried running outside today for the first time since I was about 5, and it could have gone better. I made it a total of about 10 minutes and I maybe ran a mile. Then I started to feel sick to my stomach (though that could have been the pizza), and got a side ache and really tired. But when I'm in the gym, I can run for at least 30 minutes no problems. Any ideas of how to make my gym enduracne translate to the road? :dunno: Typically I have the exact opposite problem. When I was marathon training I could run 18 or 20 miles outside no problem (okay, maybe no problem is a bit of a stretch). I would die after 3 on a treadmill though, then get up the next morning and do 8-12 outside and feel great. I think treadmills are boring, but they also let you regulate your pace much more than you can do on your own. Temperature is another factor. Keep in mind the first 10 minutes is usually the hardest ...

I tried running outside today for the first time since I was about 5, and it could have gone better. I made it a total of about 10 minutes and I maybe ran a mile. Then I started to feel sick to my stomach (though that could have been the pizza), and got a side ache and really tired. But when I'm in the gym, I can run for at least 30 minutes no problems. Any ideas of how to make my gym enduracne translate to the road? :dunno: Typically I have the exact opposite problem. When I was marathon training I could run 18 or 20 miles outside no problem (okay, maybe no problem is a bit of a stretch). I would die after 3 on a treadmill though, then get up the next morning and do 8-12 outside and feel great. I think treadmills are boring, but they also let you regulate your pace much more than you can do on your own. Temperature is another factor. Keep in mind the first 10 minutes is usually the hardest ...