This has sort of turned into the “dumb things J.D. does” blog. Here’s yesterday’s dumb thing.

I drove to Eugene to participate in a neuroeconomics study. I spent an hour inside an MRI scanner answering questions about personal finance. For this, I was paid $120.

Because I knew I might fall asleep, I had a diet soda for lunch. Lying on my back for an hour (or more) is a recipe for slumber, even if I’m supposedly taking a survey for money. Sure enough, even with the diet soda, I was very, very groggy.

After the study, Paul and I spent more than an hour working out at the gym, and then went out for Thai food. (I could splurge — I had an extra $120!) I was still groggy, though, even though I had exercised. The sun was warm, and I had a long drive ahead, so I ordered diet soda. Three times.

“You know what I do when I’m groggy and have to drive?” Paul said. “I stop at a minimart and pick up an energy drink.”

“Like a Red Bull?” I asked.

“Sort of,” he said. “Only bigger. And with more caffeine.”

So, about half an hour north of Eugene, I pulled over to pick up an energy drink. There was an enormous selection. I had no way of knowing which one was “best”, so I just grabbed a can of something that boasted 344mg of caffeine. I drank it. I drove home.

“Are you coming to bed with me?” Kris asked at ten o’clock. I wasn’t tired.

“Uh,” I said. “It’s too hot. Plus I had too much caffeine.”

“How much caffeine did you have?” she asked, but I didn’t really have an answer. Now, a few hours later, I do have an answer. Twelve ounces of Diet Pepsi have 36mg of caffeine. By my calculations, I had four such servings yesterday, plus the energy drink, which contained the equivalent of ten similar drinks. In other words, I had a much caffeine as if I’d had fourteen Diet Pepsis.

No wonder I couldn’t fall asleep until 3 am. I probably won’t be able to sleep again until next week.