A close second? It’s too early in the day. I mean, I woke up only seven hours ago. You have to respect your circadian rhythm. Otherwise, why bother having a body clock?

Besides, I worked out three weeks ago. That should qualify as momentum. At any rate, all the experts warn against overdoing it. That’s why I underdo it. Underdoing it inevitably prevents overdoing it.

If I exercised today, I’d have to take a shower, too. That requires a lot of water. Just trying to be super-sustainable here, people!

It would also help for me actually to be in the mood to exercise. Unfortunately, I’m never in the mood to exercise. But you never know. The muse could pop in any minute now.

Starting an exercise routine can feel overwhelming. Here’s how to begin.

Besides, I already get plenty of what you call incidental exercise, the sort that accrues though normal everyday activity. I floss vigorously. I do butterfly curls with my fork while eating. It all counts.

I also have too much else to do today. I seriously doubt all those emails in my junk file are just going to delete themselves. And someone has to watch YouTube videos of babies frolicking with puppies, and vice versa.

And, I’m just too hungry to blast my quads right now. All the dietitians warn you should never do a downward dog while craving Nutella. Or while full either. Or — my personal policy — anytime between meals or snacks. If you forgo unnecessary movement, it facilitates digestion.

And what if I start my fitness routine only to wind up interrupted? Stuff always comes up. Bypassing exercise guarantees nothing can interrupt it. Ever.

If only I belonged to a gym, I would be more motivated to exercise.

Or if I had an expensive personal trainer who yelled at me in some impenetrable language.

Or even just a workout buddy who never yelled at me in an impenetrable language.

Or if sweatpants looked better on me. Or I could prevent twinges in my body in places where I never even knew I had places. Or I had the right app for tracking my metrics to the decimal point. Or my hair stayed in place while my body sweated to the oldies. Or the humidity would let up. Or I knew how to do any kind of exercise in the first place. Or I could get exactly the results I envision for myself almost instantly. Or I could maintain realistic expectations about my odds of becoming the next Mr. Olympia.

Super short workouts can be surprisingly effective

If only all those factors would converge — that, my friends, would be a game changer. The long-awaited new me — chiseled, carved, ripped, shredded and jacked to the max — would finally show up in my mirror.

Am I really asking for so much? I mean, everyone gets a little out of shape now and then.

It’s probably just my age, even though I’m still well under 100.

Just coming up with all these reasons is exhausting. I better lie down to catch my breath.

Bob Brody, a consultant and essayist, is author of the memoir “Playing Catch With Strangers: A Family Guy (Reluctantly) Comes of Age.”