So I made a post on my personal Facebook page about running intervals at 12.0 on the treadmill! I got a mixed response, some people thought I was full of it, and others said
"well your a trainer so of course you can" Well it's not quite that simple, yes I'm a trainer but that doesn't make me great at every physical feat known to man. The fact is that I'm 240lbs so 12.0 on the treadmill is pretty daring! But if I can do it, surely you can try jacking it up to 7 or 8. If your cardio workout has gotten stagnant, try this. 4.5-5.0 jog for 5 minutes to get loose, than 1 minute intervals going 7.0 followed by walking for 1 minute at 3.3 to bring your heart rate down. After you get a couple under your belt at 7.0, kick it up to 7.5 then 8.0. You'll find that the time goes by much faster this way and by adding intervals as a regular part of your routine you'll soon find those longer runs at 5.5 and 6.0 to be much easier.