The Physiology of Endurance Running Podcast · Dan Nash and Owain Zerilli

Road to Valencia 2025 - 9 weeks to go

·1 hr 38 min·5 clips

Jake Smith dropped to 51kg in Uganda until his body completely gave out, forcing him to call his parents in tears.

This episode features hosts Dan and a guest co-host, Jake Smith, a professional runner with a 2:11 marathon personal best, discussing Jake's recent half-marathon performance and his recovery from Relative Energy Deficiency in Sport (RED-S). Dan is a runner who recently placed as the first Welshman at the Cardiff Half Marathon, and the regular host Jen is absent due to her wedding. Jake Smith details his experience with RED-S, which involved years of underfueling, leading to a weight as low as 51 kilograms, multiple stress fractures including one in the sacrum, and osteoporosis. He explains his two-year recovery process, which included a five-week complete break from all training and working with a coach on a long-term plan targeting the 2028 Olympics. Jake notes his current weight is 10 kilograms heavier, his recent blood results are the healthiest they've ever been, and his half-marathon average this year is 62:40. A surprising insight is Jake's claim that a sacrum stress fracture in an athlete, without impact, strongly indicates underfueling, a point he illustrates with reference to triathlete Lionel Sanders. He describes a pivotal moment in Uganda where, despite no injury, he physically could not run up a hill and had to call his parents in tears. Jake argues that power and strength, facilitated by increased weight and consistent gym work, are now key to his performance, countering common narratives about race weight. The conversation covers Jake's remaining races for the year, the Great South Run and a 15k in the Netherlands, where he hopes to compete against a strong European field. Dan recounts his own training week leading into the Valencia Marathon, which included a reduced volume "absorb" week following a hard prior session, with a specific treadmill workout targeting a heart rate between LT1 and LT2. He describes spectating at the Cardiff Half, playing a game of spotting runners with mismatched bib names. The tone is conversational and supportive, blending personal training updates with deeper educational discussions on athlete health. The style is informal, featuring banter about Jen's marriage, birdwatching apps, and Strava habits alongside serious topics. Endurance runners and coaches interested in the realities of high-level training, injury prevention, and RED-S recovery would find this episode valuable. Listeners seeking a highly structured, purely scientific breakdown of physiology might find the casual, anecdotal style less appealing.

As heard by us

A practical training check-in that feels like runners thinking out loud.

Road to Valencia starts with nine weeks to go and uses Dan's Cardiff Half result as the main bit of proof that the training is landing, even after a few rough races.

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Why you'd press play

A Valencia check-in built for your easy-run brain and your training log.

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