I went to do a timed mile today. It was 54 out so not that cold, well, its cold for me I live in the deep south. I have ran well in the 50's before. So I start my timed mile and I was so tired and out of breath, that I just stopped half way through. My mile pr is 8 min. yeah Im what people here would call a "hobby jogger" I started running to lose weight started @ 230, now 180 @ 5'10. I recently went low carb to peed up weight loss, but today I sorta felt tired even though im usually not. I also didn't warm up to good because I was in a rush. Not really sure how much I should warm up anyway. So which one killed my run.