30-minute treadmill interval workout

I hate the treadmill. I (not so) affectionately call it the ‘dreadmill’ and really only use it when I have to. With a half marathon looming in less than nine weeks and below-freezing temps outside, I have to use it now. The only way I can tolerate it is to a) listen to music and b) do some kind of interval workout. Switching the speeds gives me something to focus on aside from the slowly moving timer. 

For this workout, I would bump up the speed at different times and then lower it 0.1 each minute. For example, check out minutes 23-25. At 23 minutes into the workout, I moved the speed up to 7.2. At 24 minutes, I moved it down to 7.1. At 25 minutes, I moved it down again, this time to 6.7 to start the next set. Make sense? (If not, please tell me so that I can clarify it!)

*Disclaimer: Remember, I have no fitness training. While I’ve been a runner for years, I can’t tell you if this is a good/safe workout for you. I’m just telling you what I like to do. [end disclaimer]