Exercise problem/concern

[RP33]

I posted this in the Ask the Trainer Section, but I wanted to post it here as well because I found it somewhat concerning and would like to solicit answers from as broad a spectrum as possible. If that's a problem, a MOD can feel free to delete this thread:

OK, so I'm about 20-30 pounds overweight at the moment and I've decided to get back into decent shape. I've been going on long-ish bike rides, going to boxing classes etc., and I recently got a membership to a local gym. I'm just focusing on cardio at the moment, and I had my first real workout there yesterday. It was pretty mellow, I basically just did about 20 minutes on the stairmaster-thingy (I believe that is the technical term) at a fairly low rate (I think it said I did about 70 stories) and then I did about 10 minutes on the eliptical machine. So far, so good.

So today, I went back to the gym, did another 20 minutes on the stairmaster-thingy, this time at a slightly higher rate (I think I did around 80 stories this time), then I went to the treadmill and did about 15 - 20 minutes there (I ran about a mile - I know, I'm slow) with no break inbetween either workouts. Through out the run on the treadmill, I kept track of my heartrate - it was hovering between 145 and 170 (it was usually between about 150-165), which I think is probably too high for a fat fuck like myself. Anyways, the problem is that when I stepped off the treadmill, I got incredibly dizzy. It was like the world was still on the treadmill while I was standing still. This began to subside after about 20-30 seconds or so, though I felt a little dizzy for a little while afterwards.

So, my question is, did I push myself too hard? Getting dizzy like that kind of freaked me out...

this used to happen to me, the dizzy feeling.. not sure if anyone mentioned this previously, but what helped me:

the cool down..

it's underrated..

After running at a high intensity, i don't just stop and jump to the side and let the treadmill keep on going, i SLOWLY decrease the speed.. it takes a bit of extra pushing to get through it, but i never feel dizzy when i slowly let my heart rate drop..

[Scrap]

Nothing to worry about Mate, There was a guy I knew with the same problem. He lived for a month after telling me of His problem

[Scrap]

Treadmills cause this, the problem is feel the body isnt being used as nature intended, there lies the problem. Your Adductors are working as they should but your Abductors are not, the machine is doing it for you Hence the inbalance when you get of, Prerocreation is the cause. A good stretch can Help.

[Howlin Mad Missy]

CFH - if it's the treadmill, just don't jump straight off. If you've included a walking cool down when the machine has stopped give your legs a good ole shake and slowly step off the machine. Give em another shake before walking to your next exercise.

[CFH]

Thanks to everyone who responded. As for the cool-down suggestions, I did do a bit of a cool-down, but it was only for about 2 mins or so.