One moment I was riding my bike; the next thing I remember, I was sitting on the ground talking to an EMT from the ambulance parked nearby.

This happened three weeks ago. I went to the emergency room, had a few CT scans and an MRI. The best theory is that I had a seizure. So now I am on anti-seizure medication, and am legally forbidden to drive a car for six months.

I was wearing a helmet, and was on a bike path, not a street. The physical effects were minimal: a sore shoulder and some road rash.

There was no eye-witness, so doctors guess I fell because I blacked out rather than the other way around. During the time I don’t remember, I called my wife and told her where I was, so maybe I was never truly unconscious? No one knows.

I usually have a low heart rate (a resting pulse of 50 bpm is not unusual), so maybe it was cardiac-related? I’m wearing a heart monitor to collect data.

The first week was hard because I felt completely limited in what I could do. All spring I had been feeling strong and capable in physical activities, and now I was finding a short walk difficult.

At first the anti-seizure meds made me tired and a bit fuzzy-headed. But we’ve adjusted them, and/or I’m adjusting to them, and/or my concussion is wearing off, so I feel more like myself. I’ve gotten back on the bike (though not alone), and have been swimming in the ocean, same as every summer.

I have more visits coming up with more doctors to try to understand what happened, and what might happen. I doubt they will be able to completely rule out a seizure, so I may be on meds for quite some time. Their recommendations are quite cautious (“Don’t take a bath without supervision”), so now we are making absurd trade-offs and considerations of risks and possibilities.

It’s unsettling to have lost time without a clear explanation, and especially unsettling to think that it could happen again at any time. I’m not sure what to do with that.