Treadmill Running

I have to admit, I am so wimpy with my exercise when I get to hot. Currently I am running throughout the week on my treadmill and I'm finding it harder and harder to keep up the running as the temperature of the room gets higher and higher. I do have fans blowing on me, but somehow it doesn't make enough difference. Maybe it's a combination of the heat and boredom, but I do not reach my mileage goals very often when I have to do it on a treadmill. Ironically, though, the higher my goals, the longer I run. I wonder if I can actually trick my mind into thinking I'm going to run a really long run, when really I'll just stop when I reach my true goal....