So I ran a marathon at the weekend.
I was going to say “my first marathon” - which it was, my first I mean - but that makes it sound like there are going to be many, which uh I don’t intend so much. Let’s see.
I expected a marathon to be hard. It was harder than I expected in a super interesting way.
Goals: (a) get round and (b) hit a target time of 3:45 if poss.
My time was 3 hours 40 minutes 12 seconds. I’m proud of that ngl (and wish I’d done better).
Why is a marathon hard? Energy.
26 miles is an interesting distance because it’s more than your body can do naturally without being genetically freakish.
I wouldn’t be me if I didn’t treat this whole thing as an excuse to get really nerdy about my body as a systems problem.
So I’ve been learning how energy works in the body, and as I understand it when you’re using your muscles you’ve got three energy sources.
- Glucose. In your blood, comes from food. There’s barely any calories here – but if you eat, that’s where it goes first.
- Fat. You can burn fat but it’s slow… which is a shame because 90% of your body’s stored energy is in the form of fat. So it contributes only about 10-20% to the mix, more as a race goes on. Really experienced runners will have more fat burning in the mix.
- Glycogen. Glycogen is the main source of energy. It’s stored glucose, and converts to glucose before it can be used. Your body carries about 1,600–2,000 calories of glycogen.
Glycogen is stored mainly in the muscles. There are up to 1600 calories in the muscles, and it can only be used for those muscles. Also about 400 calories in the liver, and that can be transported anywhere.
One thing I learned about glycogen which I’d never really thought about is that energy has a weight in your body. Of course it does.
Glycogen is about 4 calories per 1 gram. But to store it, it has to be bound to water, another 3g per gram. So your 2000 calories of glycogen is about 2kg (4.4lb) weight, and you lose that as you run.
(That water aspect is itself fascinating. Using glycogen liberates water, so you self-hydrate to a degree.)
Now once you add all of this up, you’ve got a deficit.
Rule of thumb you burn 100 calories per mile. i.e. marathon = 2,600 calories.
(For comparison I eat a little under 1,800 calories/day.)
So this is mathematically not possible: your carrying capacity is max 2,000 calories glycogen, another couple hundred contributed by burning fat. Still 400 calories to find.
How do you close the gap?
- Train and get biomechanically more efficient at moving
- Train and get better at storing and converting glycogen (up to that 2,000 calories level)
- Train while fasting to improve fat burning
- Carb load: you can temporarily store more glycogen than usual, so load up with carbs 48 hours before a race
- Eat on the way: running gels contribute 80 calories each of glucose into your blood, and that slows glycogen conversion. I had four gels on the way round. They take about 30 minutes apiece to hit your system.
Part of what’s going on during training is all these bodily adaptations and it’s amazing to see it happening. But yeah, you can’t do a marathon without doing all of the above, the distance is just enough to get you into that deficit territory. I used to think that 26 miles was a kinda arbitrary distance, and now I realise that it makes it a finely poised competition you can have with yourself.
I haven’t talked about electrolytes and water, and that’s because they never really popped up as issues for me during training.
But that’s what bit me.
Training and will
I think I’ve said before that training for me is about four things: heart, puff, muscles, will.
I help my “long will” by maintaining a training streak. (And part of what I’m training in that time is my “short will”, which is the will to keep going in the moment even when I’ve reverted to my stupid glucose-starved monkey brain.)
My streak: I’ve been training at 20 miles a week for about 10 months, since 27 May 2024, and that’s doubled as I’ve got closer to this race.
The main thing I’ve battled has been to come to terms with the fact that my days of personal bests are mostly behind me. Even when I’m at peak fitness right now, I’m a long way off where I was at peak fitness five years ago.
My first marathon was originally going to be back in 2020 and it was cancelled, being 3 weeks into the first pandemic lockdown. It was enormously disappointing and, for a variety of reasons, I was on for a great time back then.
Since then I’ve had knee injuries, Achilles injuries, IT band imbalances pulling my hip (and knee) off, months getting my puff back post bouts of Covid… and of course 5 years older.
btw I’ll mention that knee injury again.
But yeah, since May 2024 I’ve kept up this streak. I’ve taken part in one half marathon race in that period, which is a tricky moment in itself: training up to it is motivating, but extrinsic motivation eats intrinsic motivation for breakfast and it takes will to re-find motivation after the race is done. And my intrinsic motivation has had to shift from ever-increasing PBs to… something else. Enjoying being outside I guess!
Anyway I made it through training. I was pretty much done with it by the end tho.
The race itself
By the time I decided that I was going to do an actual race, and it seemed like I probably wouldn’t get injured again, and I’d be fit enough, all the high-profile marathons were full up. But Southampton had space, and you know what, that’s not so bad. It’s the city I grew up in.
The course looked hilarious. I’m running past places that I would hang out as a kid, going through parks I used to just kind of loiter in when I was 15, past the casino my mate worked at, through the stadium of the local football team, across the common I did cross-country at school, those kind of places. So it was a race of old haunts, a nice place to be.
The race went 81% well.
The start was a little chaotic and congested.
My half marathon pace felt very comfortable and so I was ticking along doing that.
What was tricky was that at 21 miles I felt pain in my knee, a bit like somebody jabbing into it HARD with a screwdriver and I couldn’t put any weight on it. My muscles had tightened up to the point it was pulling my knee out, a recurrence of that old knee injury. (If I’m being honest it had been niggling for two weeks and, if it hadn’t been for race day, I never would have risked a long run.)
So, after stopping a couple of times to stretch that out, cursing and grimacing, which at least kind of got me moving again, then cramp started.
My mental model of what occurred is that my knee made me stop, then my legs forgot their rhythm and fell into a new and dysfunctional pattern.
Now I’ve had cramp before, I suppose, but never like this.
Both calves. I can only describe cramp as having very hot animals like maybe like the size of mice forcing and crawling around under my skin all over my calves and the burning pain was extraordinary. I was barely able to walk so I would walk stubbornly and then start trying to jog a little, then the roaming boiling knots would come back and overwhelm me. Uphill was especially bad.
At a water station, a volunteer there checked in with me and he offered to help with my calves. He did something which I didn’t expect, which was not to massage them, but basically to run his hands up and down my calves, one at a time, not too hard, and that seemed to reboot them.
A superhero.
What is cramp anyway?
So I looked into cramp afterwards, and it is not, as I grew up thinking, lactate buildup.
Cramp is neuromuscular fatigue and (from my very, very partial understanding) it seems like what happens is the nerve junctions between the ends of the nerve and the muscles, these little junctions run out of the electrical juice the nerves sit in, and the juice is a combination of salt and water. The salt being your electrolytes of course, and they just dry out or stop conducting, and your nerves can’t communicate with the muscles properly, and your muscles go haywire interpreting the static.
It was wild after the race when I lay down and my wife was massaging my calves because of the cramp pain and she said to me “what are you doing with your legs?”
I was like “what do you mean?” – I couldn’t feel anything. Then I looked at my calves and I can only describe it as some kind of Cronenbergesque manifestation of worms crawling underneath my skin.
You see every so often those time-lapse videos of chemical reactions with bimodal stable states in a petri dish doing those wild, curved, radiating geometric patterns, Turing patterns. My muscles were doing the same, writhing underneath my skin, that’s all I could think of to look at it. This is what neuromuscular fatigue is, this misfiring.
It seems like when I was helped by that kind person at the water station, the movement he was doing on my calves was indeed like resetting the muscles – a new input stimulus to override the misfiring signals, and give my legs space to remember what they were supposed to be doing.
My model of what happened (stopping because of my knee, legs forgetting what to do) feels correct to me. My calves were overworked, compensating for my knee, then got confused. I have a picture of my legs as octopus tentacles, these semi-independent limbs that have their own rhythms and habits and - when push comes to shove - I have to negotiate with them.
Now the main factor, really, is that it was the second hot day of the year.
It was 20C by the time I finished, and I’ve done most of my training between -5C to +5C. It’s only recently hit 12C. So I’ve barely done any warm day training at all.
So I will have been dehydrated I’m sure, and lost more salt than I was expecting, those juicy nerve junctions parched and grainy. Then it all happened, this unfamiliar cascade.
I had enough energy though.
Now my monkey brain…
I hobbled for a mile, managed to get my knee stretched out, reset my calves, and found a pace slow enough that cramp wouldn’t overtake me but fast enough that I could still call it running, and red-lined the final three miles like gunning a car in second gear and made it over the finish line.
So would I do it again?
I went into the weekend saying this was going to be my one marathon. For closure because of the one I didn’t get to do before.
It was harder than I expected, even knowing it would be hard.
After I’d done my final 21 mile training run (you don’t go any further than that, then you taper for two weeks), I was like: I don’t know if I have another five miles left in me. It was the first time in my training that I felt doubt.
I assumed that I’d cover that 5 mile gap with a combo of energy and will. i.e. the ingredients that had got me this far.
But they weren’t what mattered. The experience beyond 21 miles was uncharted.
What this says to me is that when you go to extremes, new things happen?
There are new experiences to be found, when you go past your limits, which aren’t like the old ones scaled up. They’re something distinct. Unanticipated and unanticipatable.
I don’t know how to explain it better than that! It seems to me that this is true of so many things. The only way to know what it’s like to run mile 22 is to run 21 miles first, you can’t shortcut your way there.
The only way to know what you’ll write as your million-and-first word is first to write a million words.
Etc.
So would I do it again? I went into it saying no. One and done.
That said, lying there under the blue sky watching my muscles writhe around, in the park in Southampton city centre, there was a part of me going, I think I could have done better knowing what I know now about race strategy.
Actually I’m sure I could.
And there’s something I saw about myself, I think, at the end of the travel upriver, into the capillary-end heart of that journey, that place of pride and brutal will – and I can’t see it clearly from my vantage point of sitting at my laptop. I want to visit that place again.
Anyway.
Race time of 3:40, hit my goals, slightly better than actually. I got a medal (we all did). Where I came is number 249 out of 1,337. 62/199 if I look at my category, which is male veterans. Pleased, yes, and also would like to have done better.
And what an experience to experience my body as pure system, this kind of metabolic system which is just astounding and fascinating, and has so many nuances and edges; I’m learning a new landscape, a geography, this surface of a metabolic manifold of surprisingly few parameters really.
I feel so in tune with and in touch with myself. If I have any regrets about my running career it’s that I wish I’d started running earlier than my early 30s, and I wish I’d started taking it more seriously earlier than I did.
And that’s another lesson I can take more generally which is to try more and if I’m going to commit, then commit faster.
So I ran a marathon at the weekend.
I was going to say “my first marathon” - which it was, my first I mean - but that makes it sound like there are going to be many, which uh I don’t intend so much. Let’s see.
I expected a marathon to be hard. It was harder than I expected in a super interesting way.
Goals: (a) get round and (b) hit a target time of 3:45 if poss.
My time was 3 hours 40 minutes 12 seconds. I’m proud of that ngl (and wish I’d done better).
Why is a marathon hard? Energy.
26 miles is an interesting distance because it’s more than your body can do naturally without being genetically freakish.
I wouldn’t be me if I didn’t treat this whole thing as an excuse to get really nerdy about my body as a systems problem.
So I’ve been learning how energy works in the body, and as I understand it when you’re using your muscles you’ve got three energy sources.
Glycogen is stored mainly in the muscles. There are up to 1600 calories in the muscles, and it can only be used for those muscles. Also about 400 calories in the liver, and that can be transported anywhere.
One thing I learned about glycogen which I’d never really thought about is that energy has a weight in your body. Of course it does.
Glycogen is about 4 calories per 1 gram. But to store it, it has to be bound to water, another 3g per gram. So your 2000 calories of glycogen is about 2kg (4.4lb) weight, and you lose that as you run.
(That water aspect is itself fascinating. Using glycogen liberates water, so you self-hydrate to a degree.)
Now once you add all of this up, you’ve got a deficit.
Rule of thumb you burn 100 calories per mile. i.e. marathon = 2,600 calories.
(For comparison I eat a little under 1,800 calories/day.)
So this is mathematically not possible: your carrying capacity is max 2,000 calories glycogen, another couple hundred contributed by burning fat. Still 400 calories to find.
How do you close the gap?
Part of what’s going on during training is all these bodily adaptations and it’s amazing to see it happening. But yeah, you can’t do a marathon without doing all of the above, the distance is just enough to get you into that deficit territory. I used to think that 26 miles was a kinda arbitrary distance, and now I realise that it makes it a finely poised competition you can have with yourself.
I haven’t talked about electrolytes and water, and that’s because they never really popped up as issues for me during training.
But that’s what bit me.
Training and will
I think I’ve said before that training for me is about four things: heart, puff, muscles, will.
I help my “long will” by maintaining a training streak. (And part of what I’m training in that time is my “short will”, which is the will to keep going in the moment even when I’ve reverted to my stupid glucose-starved monkey brain.)
My streak: I’ve been training at 20 miles a week for about 10 months, since 27 May 2024, and that’s doubled as I’ve got closer to this race.
The main thing I’ve battled has been to come to terms with the fact that my days of personal bests are mostly behind me. Even when I’m at peak fitness right now, I’m a long way off where I was at peak fitness five years ago.
My first marathon was originally going to be back in 2020 and it was cancelled, being 3 weeks into the first pandemic lockdown. It was enormously disappointing and, for a variety of reasons, I was on for a great time back then.
Since then I’ve had knee injuries, Achilles injuries, IT band imbalances pulling my hip (and knee) off, months getting my puff back post bouts of Covid… and of course 5 years older.
btw I’ll mention that knee injury again.
But yeah, since May 2024 I’ve kept up this streak. I’ve taken part in one half marathon race in that period, which is a tricky moment in itself: training up to it is motivating, but extrinsic motivation eats intrinsic motivation for breakfast and it takes will to re-find motivation after the race is done. And my intrinsic motivation has had to shift from ever-increasing PBs to… something else. Enjoying being outside I guess!
Anyway I made it through training. I was pretty much done with it by the end tho.
The race itself
By the time I decided that I was going to do an actual race, and it seemed like I probably wouldn’t get injured again, and I’d be fit enough, all the high-profile marathons were full up. But Southampton had space, and you know what, that’s not so bad. It’s the city I grew up in.
The course looked hilarious. I’m running past places that I would hang out as a kid, going through parks I used to just kind of loiter in when I was 15, past the casino my mate worked at, through the stadium of the local football team, across the common I did cross-country at school, those kind of places. So it was a race of old haunts, a nice place to be.
The race went 81% well.
The start was a little chaotic and congested.
My half marathon pace felt very comfortable and so I was ticking along doing that.
What was tricky was that at 21 miles I felt pain in my knee, a bit like somebody jabbing into it HARD with a screwdriver and I couldn’t put any weight on it. My muscles had tightened up to the point it was pulling my knee out, a recurrence of that old knee injury. (If I’m being honest it had been niggling for two weeks and, if it hadn’t been for race day, I never would have risked a long run.)
So, after stopping a couple of times to stretch that out, cursing and grimacing, which at least kind of got me moving again, then cramp started.
My mental model of what occurred is that my knee made me stop, then my legs forgot their rhythm and fell into a new and dysfunctional pattern.
Now I’ve had cramp before, I suppose, but never like this.
Both calves. I can only describe cramp as having very hot animals like maybe like the size of mice forcing and crawling around under my skin all over my calves and the burning pain was extraordinary. I was barely able to walk so I would walk stubbornly and then start trying to jog a little, then the roaming boiling knots would come back and overwhelm me. Uphill was especially bad.
At a water station, a volunteer there checked in with me and he offered to help with my calves. He did something which I didn’t expect, which was not to massage them, but basically to run his hands up and down my calves, one at a time, not too hard, and that seemed to reboot them.
A superhero.
What is cramp anyway?
So I looked into cramp afterwards, and it is not, as I grew up thinking, lactate buildup.
Cramp is neuromuscular fatigue and (from my very, very partial understanding) it seems like what happens is the nerve junctions between the ends of the nerve and the muscles, these little junctions run out of the electrical juice the nerves sit in, and the juice is a combination of salt and water. The salt being your electrolytes of course, and they just dry out or stop conducting, and your nerves can’t communicate with the muscles properly, and your muscles go haywire interpreting the static.
It was wild after the race when I lay down and my wife was massaging my calves because of the cramp pain and she said to me “what are you doing with your legs?”
I was like “what do you mean?” – I couldn’t feel anything. Then I looked at my calves and I can only describe it as some kind of Cronenbergesque manifestation of worms crawling underneath my skin.
You see every so often those time-lapse videos of chemical reactions with bimodal stable states in a petri dish doing those wild, curved, radiating geometric patterns, Turing patterns. My muscles were doing the same, writhing underneath my skin, that’s all I could think of to look at it. This is what neuromuscular fatigue is, this misfiring.
It seems like when I was helped by that kind person at the water station, the movement he was doing on my calves was indeed like resetting the muscles – a new input stimulus to override the misfiring signals, and give my legs space to remember what they were supposed to be doing.
My model of what happened (stopping because of my knee, legs forgetting what to do) feels correct to me. My calves were overworked, compensating for my knee, then got confused. I have a picture of my legs as octopus tentacles, these semi-independent limbs that have their own rhythms and habits and - when push comes to shove - I have to negotiate with them.
Now the main factor, really, is that it was the second hot day of the year.
It was 20C by the time I finished, and I’ve done most of my training between -5C to +5C. It’s only recently hit 12C. So I’ve barely done any warm day training at all.
So I will have been dehydrated I’m sure, and lost more salt than I was expecting, those juicy nerve junctions parched and grainy. Then it all happened, this unfamiliar cascade.
I had enough energy though.
Now my monkey brain…
I hobbled for a mile, managed to get my knee stretched out, reset my calves, and found a pace slow enough that cramp wouldn’t overtake me but fast enough that I could still call it running, and red-lined the final three miles like gunning a car in second gear and made it over the finish line.
So would I do it again?
I went into the weekend saying this was going to be my one marathon. For closure because of the one I didn’t get to do before.
It was harder than I expected, even knowing it would be hard.
After I’d done my final 21 mile training run (you don’t go any further than that, then you taper for two weeks), I was like: I don’t know if I have another five miles left in me. It was the first time in my training that I felt doubt.
I assumed that I’d cover that 5 mile gap with a combo of energy and will. i.e. the ingredients that had got me this far.
But they weren’t what mattered. The experience beyond 21 miles was uncharted.
What this says to me is that when you go to extremes, new things happen?
There are new experiences to be found, when you go past your limits, which aren’t like the old ones scaled up. They’re something distinct. Unanticipated and unanticipatable.
I don’t know how to explain it better than that! It seems to me that this is true of so many things. The only way to know what it’s like to run mile 22 is to run 21 miles first, you can’t shortcut your way there.
The only way to know what you’ll write as your million-and-first word is first to write a million words.
Etc.
So would I do it again? I went into it saying no. One and done.
That said, lying there under the blue sky watching my muscles writhe around, in the park in Southampton city centre, there was a part of me going, I think I could have done better knowing what I know now about race strategy.
Actually I’m sure I could.
And there’s something I saw about myself, I think, at the end of the travel upriver, into the capillary-end heart of that journey, that place of pride and brutal will – and I can’t see it clearly from my vantage point of sitting at my laptop. I want to visit that place again.
Anyway.
Race time of 3:40, hit my goals, slightly better than actually. I got a medal (we all did). Where I came is number 249 out of 1,337. 62/199 if I look at my category, which is male veterans. Pleased, yes, and also would like to have done better.
And what an experience to experience my body as pure system, this kind of metabolic system which is just astounding and fascinating, and has so many nuances and edges; I’m learning a new landscape, a geography, this surface of a metabolic manifold of surprisingly few parameters really.
I feel so in tune with and in touch with myself. If I have any regrets about my running career it’s that I wish I’d started running earlier than my early 30s, and I wish I’d started taking it more seriously earlier than I did.
And that’s another lesson I can take more generally which is to try more and if I’m going to commit, then commit faster.