A 22-year old runner died in the Chicago Half Marathon yesterday, probably a victim of the record high temperature. When I ran the Nashville Half Marathon in 2009, also in record high temperature, we had a similar experience: another young runner died. Why does this happen?

I found myself asking this question as I went for my morning run today. With 101 degrees forecast, we are under a weather advisory, with the National Weather Service advising us to “reschedule strenuous activities to the early morning or mid- to late-evening hours.” I intended to take a long run this morning, but decided to cut it short when I realized how hot I was getting.

As runners, we are always tempted to push past our limits: it’s in our nature to see how much harder or faster we can run. With experience, though, we learn that sometimes pushing too hard can be dangerous: we want to live to run another day! It’s generally the younger, less experienced runners that succumb to the heat.

The lesson? Know when to quit! During the 2009 Nashville Half Marathon, I recognized that I was becoming dehydrated and overheated, with a section that had a paucity of water stations. I didn’t drop out, but I decided it was safer to quit running and walk until I could obtain some relief. No, I didn’t beat my anticipated time, but I finished strong and healthy, and was able to run again in 2010.

It’s fun to break your personal record, but not if you lose your life in the attempt.