Yesterday afternoon, at a quarter to three, halfway up Kite Hill on Hampstead Heath, I died. Died in the sense that my heart, according to all the instrumentation I had, stopped beating. Which is a pretty conclusive sense.

The instrumentation in question was a heart monitor, which I started wearing for my runs on Hampstead Heath because I read something somewhere about how, if you put too much strain on your heart, then you won’t burn fat as efficiently as you could. And burning fat is why I run on Hampstead Heath. It is not because I desperately want to get to the other side. Or because I like buying ugly shoes. Or because it is a good way to meet dogs and perverts.

So anyway, I did all the maths that told me I ought to be throbbing at about 140bpm while jogging normally and then I bought this contraption and discovered that I was, and had for years, been running at 170bpm and it was no wonder I was still a fat bastard and often felt like the Scorpion King was squeezing the blood out of my heart with his fist. So I determined to slow to 140, but that turned out to be what I was doing just walking to the park. For some weeks, my watch would not allow me to go near hills at all.

A year later, and I’m good and fit now and can move at a fair lick up decent slopes without worrying my monitor too much (there’s a strap round my chest that transmits my pulse to an ugly, grey digital watch on my wrist), and I wear the thing mostly for something to distract my mind.

You see, I do not listen to music when running. My time on the Heath is thinking time, consolidation and reflection time, a time when the inner tumult of scary thoughts can even out in time with the beat of your footsteps on the ground and the heave of your breathing, and the metronomic thrum of your heart… Which of course can get pretty boring. So then you have this great thing where you can see what various different things do to your heart, see the bpms falling off as you coast downhill, but soaring again when a girl who really should have invested in a proper sports bra comes bouncing up the other way, dropping when you pause to take on water at a fountain, then going off the scale as you see three magpies tearing apart a baby bunny.

You get to believe pretty much everything your wrist-mounted oracle tells you and so when, in the middle of a game of let’s-see-if-I-can-guess-my-heart-rate-after-50-yards-of-hopping, I looked down at its face and saw not the “167” that I had estimated blinking back at me, but a very sobering “00”, I stopped.

My first thought was, “Wow. I’m super-fit. I’m doing it without my heart beating at all” – because 45 minutes hard exercise alone in the rain does weird things to your mind.

And then I thought, “No, wait, God. I’m dead,” for very much the same reasons as above. And for a minute there, or at least a few seconds, I really thought I was. On the Heath, you see, the Heart Monitor becomes God. It says how long I’ve been running, how long till I can go home, it says the time, it says what the temperature is and what the weather is like, and it says exactly what my heart is doing. And it said my heart was not beating.

Instinctively, I grabbed at my wrist for a pulse, at the same time worrying that if I was dead I would not be able to feel if I had a pulse or not. But I had one. “Phew,” I thought. “It must be something wrong with the monitor.” Genius.

But still I had my doubts. And then, as the rain lashed down and I began to shiver, I saw that my watch also thought it was 29 degrees and “dry”. And that it was 17 minutes to midnight. And only then was I truly convinced that the “00” was an error.

But still I did not feel quite right. However much you work to get your heart rate down, you never expect to see “00” on the screen. It had occurred to me before that if I were ever to die on the Heath, struck down by the heart attack I was, oh so ironically, trying to stave off, the monitor, when my body was found, would be reading “00”, and how horribly poignant that would be. I had, I felt, had a glimpse of a detail from the moment of my death.

And so I walked the rest of the way home. And when I arrived in my road, soaked through and looking, I guess, pretty drained, I saw Kurt, who lives a few doors down.

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