I tried finding info on this but couldn't. Hopefully this isn't a dumb question-- I started HIIT; I just run at the local track. 15 seconds on 40 seconds recover. First off, how many days a week should I be doing this? Also, depending on that answer, can I also do maybe a half hour of elliptical or a 10 mile bike ride as well? I enjoy riding the bike on hot days, but will sacrifice this if it will fall under 'over training'. I lift 4 days a week...M T T F, if that matters Thanks for any info you can give me.