First of all, what are some downsides to HIIT? I have been looking through some threads and people are saying you can injure yourself with this.

I've never tried it but I'm intrigued and just wanted to know any precautions, etc.

ALSO, I'm in awe at some of you that talk about running in the cold like it's a good thing. I get you when you say you don't get as hot and heated and sweaty, but damn, the lungs. My lungs BURN and hurt soooooo bad especially when I finish for a few hours it feels weird and I hate it. Feels like I'm killing my lungs.

You're lungs burn too in the cold, right? Do you just run through the pain?

well i just saw there is another forum for HIIT. sorry i posted it here.

would still like your responses though...

I tried HIIT for the first time 2 days ago (sprint 30 seconds, run 1 minute, walk 3 minutes). It wasn't as bad as I had thought it would be. I'm planning to take out the 3 minute walk next time I do it and change it to sprint 30 seconds, run 2 minutes.

I've ran in the cold a few times and I didn't really have any problems with my lungs and the cold air. My biggest problem with it is that the faster I run the harder the cold wind slaps against your face T_T.

Also, from what it seems, theres alot of people here who use HIIT for weight loss. Would HIIT be good for increasing your speed as well though?