This past Saturday I ran 19 miles around Lake Hefner – my first really long run since the OKC Marathon. Oh, I have done some half marathons since, and those have become fairly routine, but I have been feeling great and wanted to knock out a longer run and finally found the time on Saturday. I ran one lap – 9.5 miles (I can make it 10 miles if I follow the winding path) and got back to my truck, felt great, stocked up with water again, and decided now was the time to knock out a second lap. I was in a nice running rhythm, clicking of low 11-minute miles without much problem. It was starting to get hot at the beginning of my second lap as the August sun was now climbing into the sky. I ran out of water half way around on my second lap, but luckily there was a water refill fountain close by and I was able to refill my running bottles.
At mile 15 I started getting a little tired. Nothing major and my pace only slowed ever so slightly, but I knew that I needed some food. I hadn’t eaten this morning on the run and I knew I was running out of calories. I rummaged around in my running belt and found one packet of GU, which I downed. That helped for a bit but I was already in calorie depletion mode and the GU pack was just a temporary respite.
About mile 17 things were not fun anymore. My pace slowed significantly, my eyes were glazing over, and I just didn’t want to run – but had no choice since I was still a long ways from my truck. I started walking a bit and then running for a while, trying to push through. By mile 18 I was REALLY having to focus on running and I WASN’T having any fun. My mind was wandering, I had a hard time concentrating, and I was just counting down the miles until I got back to my truck. Contrast this to the 27.4 miles I ran at the OKC Marathon, where I had fun the ENTIRE run. Yea I got tired, but I was having a blast even in the late stages of the race. The difference was at the OKC Marathon I had plenty to eat along the course. On my Hefner run, I had nothing to eat but one GU pack.
In my research on the issue I learned that someone my size has about 2,200 calories available in their blood stream. After those are burned up – actually even before they are completely burned up – the body has to find calories from somewhere else. This can be fat or muscle tissue – but the body can only convert about 200 calories per hour from fat to something the cells can use. I burned about 3,200 calories on the run, so the extra calories – minus the GU pack – had to come from somewhere. Basically my body couldn’t produce enough calories fast enough, and I “bonked” – ran out of energy, gas, whatever you call it.
So now I know how important it is to eat both before and during a long run or ride. It certainly makes it a lot more fun!
Click below to see my run on Strava: