Why do I feel sick?

is what I was wondering a little over a mile into my run. I'd had a side stitch for blocks and was starting to feel like the workout was unusually hard.

Since it was hot out and I was running mid-afternoon mostly in the sun, I knew I'd have to pace myself for today's 5k run. It had been almost 2 hours since I finished lunch, so I figured I'd be ok on that front. Yet, at 1.2 miles I was not feeling great, so I stopped to rest for a couple of minutes in the shade.

After my rest, which seemed to help only somewhat, I gave myself permission to stop running at two miles if I felt I needed to. My first mile was 11:21, but I'd gone out too fast for the first 2/3 miles and had slowed down a lot for the half mile before my 1.2 mile break.

I slowed down more for my second mile. I wasn't feeling great, but I'd found a shadier route and was now ready for the slightly downhill portion of my run (the first mile being slightly uphill), so as my watched beeped that I'd hit 2 miles, I told myself I could finish off the 3.1 that I had to do.

Then I looked at my watch. Even though I'd slowed down a lot for my second mile, I clocked in at 11:29.

Something was wrong, I thought. How could I be running an 11:30 mile when I was feeling this crappy? (11:30 isn't fast for most runners, but it's one of my better splits on a day when I'm running a 5k, especially for the second mile, which is often my slowest.) Then it clicked. I was feeling that crappy because I hadn't really slowed down. This "workout mix" I have on my ipod now where every song is at least 120 bpms gets me running faster than I would normally run, so "slowing down" brings me down only to one of my brisker paces. SO, with the sun and heat and my going out too fast, I'd started to feel like crap, and then I'd never actually recovered from that because I never ran the 12 min or 13 min pace that might have allowed me to recover (even though I thought I was slowing myself down).

Having figured that out, I decided that I didn't have an excuse not to finish the 5k strong because it wasn't that I was actually sick (a worry I'd had early in the second mile) or that I was dehydrated or something. It was just that it was hot and I was running faster than I might otherwise on a hot day. So, with the last mile being mainly downhill and me no longer babying myself, I kicked out a 10:56 third mile.

All in all, my 5k (3.1 miles) clocked in at 34:52 (my fastest, I think), which is a not too shabby 11:14 average. (now, I did have that rest along the way during the second mile . . . but given that I thought I might quite before finishing two miles, I'm pretty happy with the way it all turned out.)