Before this week, I hadn't been to the gym in almost two months. Between trips and work and family illnesses I had been too busy, too sick, or too far away to go. Finally, though, I managed to get healthy and rested, and finished a big project at the office, and picked up my exercise routine where I left off. In a lot of ways it has felt like I'm starting all over again; the routines and people feel unfamiliar, and, of course, I've lost a lot of stamina during my hiatus. But it's good to be back, if for no other reason than for being reintroduced to a phenomenon that had managed to slip my mind over the course of my absence.

It all came back to me Wednesday morning, when I reintroduced myself to spin class. By about the twenty-minute mark (in an hour-long class) I was really starting to labor. My thighs were burning, sweat was pouring down my face and stinging my eyes, and my breath was coming in ragged gasps. I found myself repeating that familiar mantra in my mind: "Just two more songs. Two more songs and I'll have been here a respectable amount of time. Two more songs and I can quit for the day."

I was almost ready to quit when something strange happened, something that I had forgotten in the past two months. Completely unprompted by anything going on around me, images of Jason suddenly popped into my mind. In my mind I could see the way he holds up his arms when he wants you to pick him up out of bed, hear the gleeful sound of his shrieks when you tickle him. And with those images, this incredible feeling of peace came over me, and I found the corner of my mouth turning up in a smile.

I don't know if this is what people mean when they talk about "runner's high" or if it's just a weird trick of my consciousness, but this imagery and the Zen-like calm that comes with it is something happens to me a lot during that spin class, but rarely seems to happen elsewhere, if ever. Just when I'm feeling like I'm about to hit the wall, I'll think of the weight of Jason's head on my shoulder when he's tired, and the softness of his hair on my cheek, and I'll be recharged. It's a fleeting thing, too, something that I can never quite seem to summon on my own, or hold onto once it's there. It's usually not long before the instructor decides to kick it up to the next level, and then there's no room left in my head for anything other than the exertion.

But, man, it's worth it. If this is what marathonners experience when they run their races, I can really see the appeal.