It’s all in your head. I’m paraphrasing. He didn’t say that, but he said that.

I was following up after I fell apart spectacularly on a long, solo run last month. I followed that with a tough run in Vermont a few weeks ago, which went well, but then I had another odd wobble while training last weekend. I was concerned that I was having dehydration problems beyond my ability to hydrate and choke down electrolytes. I was worried about my heart.

It’s important to say that whatever concerns I had about my cardiac health were firmly irrational. Yeah, ok, when you flirt with dehydration and heat exhaustion your heart doesn’t love it. None of that translates directly to having a heart problem. If anything, my ability to do hard things in difficult conditions serves as a counterargument to whatever was nagging at me.

Still, you can’t fuck around.

The doctor does not think I dehydrated in the traditional sense. He thinks I had a vagal response to some stimulus that did not seem significant at the time. For example, shortly before I began to fall apart, I had a hard fall on a wet rock. Both my feet went out from underneath me. I hit the ground hard. I shook that off and kept going. He thinks it’s possible that engaged an autonomic response that clamped down on my breathing and heartrate.

A good example of a vagal response is fainting at the sight of blood. Your brain is reacting to the stimulus independent of your rational mind. When he first suggested this is what happened to me on my run, I thought, “Nope. Try again.” But I think that’s because I was already bought into the dehydration diagnosis. As we talked more, I came to see that both things could be true. I could have been in a hydration-challenged state and also had a hormonal reaction to falling that triggered my system to go into what I experienced as “managed shutdown.”

Interestingly, the other recent problem I had with what felt like dehydration followed a fall.

He ordered blood work anyway. “Let’s confirm you’re not anemic, that your electrolyte levels are good. Let’s close off those possibilities. But don’t expect an abnormal blood test.”

The biggest challenge he thinks I have is that I know bad things can happen, things beyond my control. I have to forget that. Control the things I know I can control. He said, “When you have an autonomic response, the only way to regain control is through breathing exercises. Only the lungs can override the sympathetic nervous system. You have to stop and regroup.”

This is not what I expected from a consult with an internist. But this is what the doctor said.