The Welsh runner’s race in the British capital on April 26 will be his third marathon in 20 weeks.
When Dan Osborne-Nash broke into a great marathon PB of 2:11:49 in Seville on February 23, it was a rich reward for years of superior running and intelligent application of sports science.
The 31-year-old has a PhD in exercise physiology and co-hosts a podcast called: Physiology of Endurance Running and he says he “loves numbers,” although when it comes to races over 26.2 miles, statistics only take him so far.
“I have a heart rate limit until about 25km, and then I run as hard as I can until the end,” he says. “I set myself up to know I’m going to have a good day, but then at a certain point I ignore the watch and the data and just run hard.
“I don’t care what my heart rate is in a 35km marathon. It’s going to be high and I’m going to hurt, but I have to run as fast as I can.”
His knowledge of sports science, in addition to patiently building his weekly runs to his current level of 125 miles, has seen him take a small knock off his marathon PB.
In 2016 he ran 2:27:43 in Manchester, but in 2018 he improved to 2:18:53 in Brighton. There were further improvements until he clocked 2:13:02 in Valencia in 2024 and 2:14:03 in the same Spanish city last December. Then, just 10 weeks later, in 2:11:53 in Seville this year, there has been a breakthrough so far in London, despite once again only 10 weeks between races.
“I do a lab test before every marathon and before Valencia (2025) the numbers were the best they’ve ever been and the training was the best it’s ever been,” he explains.
“I ran 4 x 4 miles under 20 minutes (for each 4M rep) and 5:20 a mile steady, so I ran 20 miles myself at 5:05 mile pace, feeling good, so I thought ‘I’m going to run 2:10-11 in Valencia’, but I ran 2:14. possibly going down with an illness on race day.
“10 weeks after Sevilla I thought I don’t need to be in better shape, just in the same way.”
However, a bit of disaster struck when he picked up a peroneal tendon injury on his way to a move to Sevilla, leading to a week of running and then a week of low mileage with cross training to get back into training.
“So until Seville I hadn’t done any big sessions and I had no idea how I was going to run,” he says. “The plan was to go out at 2:15 pace and build into that. I ran a 3:10 first kilometer and felt pretty good. I’ve got heart rate data for all my marathons, so I know what to run for each part of the race.
“I ran with Alex Milne who was sixth at the Comrades last year and ran 2:14 for the marathon and I’ve been on GB 50km teams with him twice so I know him really well and we’ve run all the way together.”
Without pacemakers, the pair helped each other out, with Milne even giving Osborne-Nash his drink bottle, and they crossed the halfway mark in just 66 minutes before closing in on a faster second half.
“We were focused, but we were also in control. Halfway through I thought we could get a 2:11 or even a 2:10 here if it’s all a dream.”
For Osborne-Nash, endurance is no big deal. In 2019, he broke the British 50km record of 2:49:01 in Romania. He also has confidence in what the numbers tell him.
“I’ve run 12-14 marathons now, and in the last 10, I’ve never blown up and nearly executed every time,” he says. “After running 2:18 at Brighton in 2019, I’ve been getting about a minute faster every year, so I feel like I know what works for me. But you can probably put limits on yourself when you’re looking at the numbers all the time.”
Osborne-Nash was born in New Zealand but moved to the UK at an early stage and grew up on Bodmin Moor in Cornwall, playing for East Cornwall Harriers and Newquay & Par AC, although he now represents Pontypridd Roadents.
He studied biomechanics at Cardiff University but didn’t really like it. More enjoyable and interesting was a placement year at Cardiff Met in their physiology labs, however, which led to a PhD, part-funded by Welsh Athletics.
He now works for Wales Athletics one day a week and also coaches All in a running club which is ruled by the former British 100km champion Lee Grantham.
“I have my running dream because I work from home most days,” she says. “I drop my son off at school and go for a run, and then I go for a run again, pick him up and do some work in the evening.”
He is based near Newport and says the running terrain is ideal as he can find long flat trails along canal paths or lots of hills if he wants to.
“I came to Cardiff Uni in 2012 and I’ve never left,” he says. “I live here, I’m married to a Welsh girl and I have a four-year-old son who was born in Cumberland. My wife also runs because we met at the running club on campus.”
It would be a dream come true to compete in the Commonwealth Games in Glasgow this year if it weren’t for the fact that the scaled-down 2026 Games will not have a race outside the stadium.
Instead, she is focusing on chipping away at her PB in London this spring.
“I’ve come back from marathons so well these days,” she says. “Super shoes make an impact. I have been running high mileage for 15 years. I’ve done 12 marathons so I know I can run the next day even though I’ll be a little sore. Then 10 days later, I’ll be in the same shape as before the marathon.”
In 2020, he brazenly tweeted the organizers of the London Marathon to suggest he could get a place on the elite start line, and he did. But now he’s fast enough to automatically earn one.
“This is probably not the best idea for most people because you don’t have enough time to improve and prepare. With the slightest hiccup, you might as well lose your training block. But if everything goes perfectly, you can jump from one marathon to another.
“By the time London comes I’ll be doing three marathons in 20 weeks and that’s definitely unusual, but with super shoes and the fact that I haven’t blown up in my previous marathons makes it possible. The key is not to rush through the build up, although I have another marathon in 10 weeks. It’s important to recover from the marathon, or to recover before training.
In London he adds: “The field looks amazing and I thought how many times I will be able to be a part of a field like this. The depth of British runners is also amazing.”
Given his obsession with numbers, has his gradual rise in mileage over the last decade been perfectly planned? “Not really.” he admits. “It was more organic and random. The marathon is pretty simple in that if you want to get better, you just have to keep running a little bit more and a little bit more intensity.”
He is also very happy to train himself for the foreseeable future. “I’ve spent my life looking at data and then telling people how to exercise, so I think I’m have train myself!? If someone told me what to do, I think I would just end up disagreeing with him.
“I share my plan with people to get some suggestions, but then it’s my wife, Jemima, who tells me if I’m doing too much, I look too crazy and need to back off a bit.”
Marathon progress
2016 2:27:43 Manchester Marathon
2018 2:22:55 Brighton Marathon
2019 2:18:53 Brighton Marathon
2021 2:29:12 London Marathon
2022 2:15:34 Manchester Marathon
2023 2:15:22 Valencia Marathon
2024 2:13:02 Valencia Marathon
2025 2:14:03 Valencia Marathon
2026 2:11:53 Seville Marathon
