Alejandro Castro came out his front door on Clare Street one Sunday last October and found the street full of people in foil blankets.
He was living a few minutes from Merrion Square at the time, so he had walked out into the end of the Dublin Marathon without quite meaning to. He picked a stranger out of the crowd and started asking him questions.
"I saw a guy, and I said, like, hey. How was the marathon?"
He wanted to know the things anybody afraid of the distance wants to know.
"How does it feel? Are you okay? Do you feel sick? How does it motivate you to finish this?"
The man, who he had never met and has never seen since, stood there and told him.
"And I kind of said, okay, right. I'm gonna run next year's Dublin Marathon."
On the last Sunday in October he does exactly that, for Make-A-Wish, and it will be the first marathon of his life.
Monterrey to Dublin
Alejandro is from Monterrey, Mexico, a city known as the City of Mountains, and has been in Ireland ten years. He works as a tax manager for an American company, fully remote.
His family are all in Mexico apart from his sister, who moved over two and a half years ago and works here as a nurse.
He became an Irish citizen last year, and he is direct about what that took.
"Many people think that it's easy, but there is a lot of bureaucracy involved."
He is equally direct about how he thinks about living here, and it is worth quoting in full because it is not the usual thing people say.
"Since I moved here I said, no, I'm here to bring or add value into the Irish culture. Bring something positive, instead of just bringing myself and then, yeah, I'm here. I want to contribute with the country."
The first two years he could not get into a professional role at all. Once his sponsorship came through, that changed.
Taekwondo at Five, and Nine and a Half Years of Kickboxing
Sport goes back as far as he can remember, and it started with his mother.
"When I was five years old, my mom took me into taekwondo, and I didn't know what that was about. I know that I was just kicking, and that was all it was about."
Football followed. He supports Manchester United. Then American football, for a local team in Mexico, and he still follows the NFL.
Then nine and a half years of kickboxing, with regional tournaments in Mexico and one international competition.
"I kind of like a little bit of everything. I like doing anything that keeps me fit and keeps me active."
He also has a joke about the real origin of his running, which he says is shared among his friends at home. Growing up in the nineties, when his mother reached for the sandal, you ran.
"Once you see it in the hand, it means danger. So I just start running. So who motivated me to get into running was my mom when I was a kid."
August 2015
The actual start was not a choice.
Two stomach surgeries for a reflux problem ended the contact sports. Once he recovered, kickboxing, MMA and American football were all closed off to him, because his body could not take the impacts.
"So I have to do something that doesn't involve impacts. I was like, okay, I should do something, because I cannot put some weight, some stones, on my body."
The first run was in Mexico in August 2015, and he remembers it precisely.
"It was quite hard. My first kilometre, I was sweating. It was too hot. I was like, oh Jesus, I don't know if I like this or not. I'm wrecked. And at the same time I don't feel energy at all."
"And even though it was only one kilometre."
He kept at it anyway, gym work alongside it, one kilometre becoming two and then gradually five. And then for years, five was the ceiling.
"I never ran more than five kilometres."
The First 5K, and the Top Twenty
In 2024 he decided that running constantly without ever racing was a waste.
"I was like, okay, I should probably get into a 5K and see how I feel."
His first race was in Ireland at the start of 2025. He had the experience every first-timer has, of being passed repeatedly, and he is competitive enough that it stung.
He finished inside the first 25.
"Being in the top 20, it was brilliant."
So he entered another one and finished 14th.
"I was like, oh, that sounds good. That's brilliant. The trainings and the runs over the week are paying off now."
What he noticed in those first two races is the thing he now talks about more than his own times. He spent them shouting at other people.
"I saw some people trying to push themselves. They were at the limits already. And I was like, hey, come on guys. You can do it."
"You always meet people, random people that you might never cross paths with again in your life, but they motivate you. Whenever you're down, there is always somebody that says, hey, come on lad, you can do it. And that brings energy up again."
Then the line that should be on a poster at every race in the country.
"I think that is better than a gel. It just brings adrenaline into your blood, and you just explode and go for everything."
The Ballot, and a Friend Called Connor
He went into the ballot for Dublin and did not get a place.
A friend called Connor, who has run the last two, explained the options. Wait for the transfer window the following year, or take a charity place.
So he started reading about charities. The first he approached was the Irish Cancer Society, and they came back positively. At the same time he was reading about Make-A-Wish, and that is where he landed.
"I know cancer is a big thing around the world, it's a really bad disease. But in terms of Make-A-Wish, when I read through their objectives, helping kids with terminal illness to make their wishes come true."
"These kids, we don't know for how long they're gonna stay here in this world. So I think it's just better to support this charity, at least to make them smile for whatever time."
The detail that settled it was something he read on their website.
"They don't get any funds from the government. Literally all the money they get is from people that donate."
What he keeps coming back to is the simplest possible version of the case.
"Making a kid smile when they get their wishes come true, I think that's what matters for me, and what motivates me to run this Dublin marathon."
The Mexican Flag and the Irish Flag
For the Dublin half marathon earlier this year, Alejandro put both flags on his shirt, the Mexican one and the Irish.
He had not anticipated what that would do.
"So many people, while I was racing, said, come on Mexican. You can do it. Keep it up."
"And here, Irish people supporting you as well, not just the relatives of whoever is racing from their side. They also support other runners. It's just unbelievable."
"You just feel part of this community, of this country."
It mattered more than he expected, because he came very close to stopping.
"I was nearly giving up. I think that was at kilometre 19."
"I was feeling too nervous. I felt a lot of adrenaline, but at the same time I didn't know how to control it. And I was like, no, no, no, I'm just gonna stop. I can't manage this."
"But once again, hitting all these crowds on the sidelines saying, come on, you can do it, you're nearly there. So it just makes you motivated, and I say, okay, last push. And I cross the finish line."
Training Alone, off a Plan He Built Himself
Alejandro is not in a running club. He has gone along to social run clubs now and then, mostly to meet people, and found the mix of nationalities and the talk about other people's races genuinely useful. But the training itself has been his own.
He built the plan out of his own research into nutrition and training, plus advice from friends who have run marathons and from athletes he follows.
One piece of advice from an athlete has done more work than the rest of it combined, and it is the thing he falls back on when he does not believe he can run a marathon at all.
Go for five minutes. If after five minutes you want more, keep going until your body says stop.
"Even on my days where I have no feeling that I'm capable to run a full marathon, I just stick with that advice. I go for five minutes. And you end up running really long distances."
"Sometimes we just need a little bit of a push."
His last long run was two Sundays before we spoke, 30 kilometres in three hours and ten minutes.
He has also come off social media for the duration, and the reason is specific.
"Seeing the stories of people getting blackouts, it kind of puts you down. I'm off my Instagram and any social media by now, because sometimes reels related to that are popping in. And I was like, no, this is not for me."
"That drains my energy, and that drains a little bit my motivation."
No Expectation
He is going into Sunday without a time in mind, and he has borrowed his race plan from a motivational speaker from his own city.
"Whenever you can run, run. If you can’t run, walk, the key point is to keep moving. But never stop moving yourself."
"If at some point my legs are not feeling okay to continue running, I'm gonna slow down a little bit my speed, but keep moving. The goal is there, the finish line."
On fuelling it is gels, taken at intervals through the race, jellies and water carried with him.
Forty-Two Kilometres, Forty-Two People
The part Alejandro has thought about most is not the training. It is who each kilometre is for.
"Each kilometre for me is gonna be in honour of people who have supported this charity, who donated to my fundraising page. I'll be dedicating one kilometre for each person that helped me."
His friends Tonalli, Diana and Vinicio will be out on the course, and they are on the list too.
The last seven he has kept for home.
"My family were seven, counting my mom and my dad. My mom, dad and five siblings. And then the last seven kilometres are gonna be dedicated to them."
"I think that's gonna make me go for everything and cross this finish line."
"My family means a lot to me, and since I moved to Ireland there is no day that I miss them."
He is going to print a family photograph and carry it round with him, along with the Make-A-Wish shirt.
"I think that is just gonna remind me what's the reason I'm racing this marathon."
"It's Like Dating"
Alejandro's advice for anybody who says they could never run is the best analogy anybody has offered in this series.
He starts conventionally enough.
"As long as your legs are okay, you just need to build that up. Everything needs to be built up. You don't get things already built up."
"No limits can stop you from running through life; the only limits are the ones we set for ourselves."
Then he gets to it.
"If you don't feel that you can run more than one kilometre, just stop. And give it another try. Because it's like dating, I will say."
"Do you go on only one date and say, oh, I already like this girl? No. You kind of build up the connection and everything. That's the same with sports."
"So first, give it a try. It might be like, oh, I don't know, I'm not sure about this. But give it another chance, and then another chance, and see if you start liking it."
"Because at some point, you may end up loving it."
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