Do you have this important leadership skill?

I’m writing today from 35,000ft, flying back from Cape Town, South Africa where I ran my 9th(!) marathon two days ago.

(Or was it just yesterday? I don’t know. I’m in that liminal space where I don’t even know if home city of Boston is even a place that exists or if I died and I’m in purgatory and I just live in this tin can where I’ve spent the past 18 hours.)

All I know is that it’s TRUESDAY. So it must be Tuesday.

A bit of backstory:

I ran this marathon because it’s part of my slow-moving, snail’s-pace unraveling of a midlife crisis. I ran my first mile — ever, of my life — when I was about to turn 40. And here we are, 15 years and nine marathons later, still not a lover of running, but a lover of having run.

There’s a joke that there are two kinds of fun. Type 1 Fun: it’s fun the whole time. Type 2 Fun: it’s fun when it’s done.

Marathon running, at least for me, is most decidedly Type 2 Fun.

But this one had a greater purpose. Two, in fact.

First, I ran it to raise money for the Parkinson’s Research Foundation. Little did I know when I first signed up six months ago that my mentor Arnie, who had struggled with Parkinson’s for 18 years, would pass away just a couple of weeks before the start. Second, I always put “LFR” in a heart on my ankle, in honor of Lisa Fucking Rosenstein — my freshman year college roommate, a marathoner herself, killed by a hit-and-run driver several years ago. I’d already carried her in Berlin, London, Tokyo, and, now, the tip of Africa.

Both Arnie and Lisa were tough-as-nails New Yorkers. And it would turn out that I needed both of them to get through what was a much tougher than nails day than I'd expected.

Because you see, oh hubris I am thee, I went out too fast. At least, too fast for me.

We were at a sub-four-hour pace through the half, which is basically Olympic-trial territory for a woman who started running at thirty-nine. Arnie was in my legs, LFR was on my calf, and both were in my heart. The Atlantic was glittering, the mountain was glowering, and I genuinely thought: Today is the day. Today is the day I finally hit a sub-four.

And then the sun came out. And the sun, my friends, had other ideas.

Around mile 14, the temperature spiked and my vagus nerve, which has a long and storied history of being a drama queen (see: my passing out in various exotic places around the globe, from the street markets in Mexico City to the South Lawn of the White House), decided to stage one of its Broadway productions. I went vasovagal: light-headed, gray around the edges, warning lights blinking on the dashboard of my body in the universal flash that screams We can do this OR we can stay conscious; pick one.

At mile 15.75, I told my running buddy to go on without me.

It turns out that was the hardest sentence to say. Go ahead, leave me, I’ve got it. Because as soon as I said, it, I knew that I'd become less resilient and less tough with every passing mile, without feeling guilty for slowing down or walking, knowing that I was no longer holding her back.

But I also knew that I only had that one choice: do it, or stay conscious.

At this point, I was having two thoughts. The first was that I was hearing the clarion voice of Sifan Hassan, who won the London Marathon and then gave the funniest interview in the world right after. The second was that I need to focus on the difference pushing through and pushing past.

Pushing through is what you do when the discomfort is the work — the hard quarter, the messy reorg, the conversation you’ve been ducking for six months. The job is to keep going.

Pushing past is what you do when the discomfort is the warning — the body, the market, the team, the dashboard telling you the conditions are no longer the conditions you planned for. The job is to recalibrate.

In 25 years of executive search and coaching, the most expensive mistake I watch senior leaders make is treating every setback as a push-through. They set the number in January. The market shifts in March. By September they’re still flogging the team toward the original target because the goal was right there in their hands at the half. The discipline they think they’re rewarding is grit. What they’re actually rewarding is the inability to read new data.

Because here's what I know to be true this week: Grit isn't the most important leadership skill; discernment is.

So at mile 15.75, I slowed way down. I walked when I needed to. I drank everything anyone handed me. I crossed the line in 4:26 — about twenty-six minutes slower than I'd hoped during the four months of training.

But the day demanded a different goal than the one I’d written down four months earlier.

Reading that, and adjusting to it, is not a consolation prize. It’s the actual job.