Some Work, All Play

We stocked up on neck floaties before this great episode! The main topic was a discussion of the constrained total energy expenditure model, which argues that physical activity will often have a smaller impact on energy expenditure than predicted. We do an interdisciplinary zoom-out to talk about how it relates to the research on low energy availability and within-day deficits. The conclusion: fueling the fire is key to prevent the...

We're doing our first early-release episode to talk about the shocking ending of the US Half Marathon Championships on Sunday. As Jess McClain was charging to victory, with Emma Grace Hurley and Ednah Kurgat poised to make Team USA with her, all 3 athletes were directed off course by a police escort motorcycle, the official lead vehicle, and a media motorcycle. 

The disgrace is what happened next. USATF (the governing body for U...

We washed all of our bowls THOROUGHLY before this great episode! A main topic was the story of US Ski Mountaineering at the Olympics, where Cam Smith and Anna Gibson had miraculous performances. 50 years from now, people will still be talking about this team with the impossible dream.

And this one had extremely interesting science that had us asking lots of big questions. We talked about a study on supershoes for slower athletes, an...

We put our hands down our pants (for warmth) before this amazing episode! The main topic revolved around the Black Canyon 100k, where Jenn Lichter and Hans Troyer set course records, and the ultrarunning took another major leap forward. We discuss what we learned before laying out an overview of our ultra training philosophy.

The sport is changing so fast that we’re almost certainly wrong (and biased) in some places. But it’s so fun...

Real talk! This episode is great, but maybe don’t listen out loud IN PUBLIC. The main training topic was a deep dive on long runs. We break down some of the competing long run theories, and how they fit into performance. The discussion ends with 5 principles to know (subject to change as competing theories duel it out).

And there were so many amazing topics! Other topics: the Real Talk Express, Megan’s mental approach to hard effort...

We cornered the market on mozzarella sticks before this awesome episode! The main topic involved our recommendations for electrolyte use in races and hard training. Sweat replacement is one of the strangest, least understood parts of athletic physiology. We give our guidelines from lots of real-world experimentation. 

And this one was full of incredible topics! Other topics: the happiest place on Earth, Megan’s first video filming a...

We ordered extra-extra cheese before this deep-dive episode. The main topic took up most of the recording today, involving a new narrative review that argues for a low-carb approach for endurance athletes.

The real-world performance benefits of carbs are clear for anyone who has traveled this path, but at the end of the day, who cares? It's just performance. The low-carb believers can get left behind and that's ok by us.

The ...

We loaded up on Vitamin D (and deodorant) before this fresh episode! The main topic was a new sodium bicarbonate study, tracking 40k bike time trial performance at altitude. It’s another brick in a really big scientific wall supporting the use of bicarb for performance. We zoom out to let you know why we think it’s also effective even in very long distances... and maybe at lower (cheaper) doses.

We also talked about Vitamin D supple...

We got our big juicy pumps for this amazing episode! We started by talking about a couple pieces of personal news, including a shockingly cool number 4 ranking in the Ultra Runner of the Year voting... and some tough health findings from an MRI. The newest shoe review is a medical boot. It’s still better than most trail shoes.

The big science discussion was on a pair of studies on advanced female runners, with both finding low carbo...

This was one of our all-time favorite episodes! We discussed takeaways from our 10 top endurance performance and health studies of 2025, full of science, recommendations, and debates. 

We don’t want to give away the countdown, but this one had everything! We’re talking fueling, training, brain health, colon health, and shoes. You just know there had to be a shoe study. Running shoes are 92% of David’s personality. 

Our mission was to...

This episode is full of the biggest predictions and most fun hot takes! We gathered 40 deep thoughts from listeners, and we had a blast responding to them all.

Topics: just about everything related to running and endurance! We’re talking shoes, races, technology, media, training, strength work, culture, thermometers in sensitive places, and so much more.

Thank you for being here for an incredible and unpredictable year. We love you a...

We realized the perils of a hurricane-force tailwind before this amazing holiday episode! To celebrate the season, we opened up the mailbag to answer listener questions on all sorts of topics.

Topics this week: what we’d save from a fire, a hot-tub experiment follow-up, Megan’s exciting news, whether we’d ever try triathlon, a vest that ejects gels, heat training submersion levels, hemoglobin A1C and REDs, iron supplementation, uphi...

We are still recovering from the laughs at the end of this episode! Before getting to that story, this one had a great training discussion on improving threshold performance. We dug down into why it’s more complex than just doing threshold workouts, and how you can put it into practice.

There was also a new study on VO2 and its relation to aerobic and lactate thresholds. We broaden it out to address recent conversations on VO2 and l...

We had one of the most fun sports-watching weekends of our lives before this great episode! The main science topic was a new study on Kilian Jornet at Western States, breaking down his fueling, the metabolic demand, and lots more. Kilian is also the 2nd author on the paper! We’ve said it before and we’ll say it again: In a world of external monitors, be the rectal thermometer.

We also talked about the amazing saga of USA Skimo’s Oly...

On Saturday, Megan broke a 15-year-old course record at Quad Dipsea! This episode shares everything about the journey in a “no secrets” style.

The record was set by Caren Spore in 2010, back when Megan was playing field hockey and her biggest runs were wind-sprints. Years later, when Megan was in medical school in the Bay Area, the Quad became a bucket list event. But it never happened—a 28 mile race with 9000 feet of vertical gain ...

We got way too invested in dog food models before this amazing episode! The main topic was a new study on passive heat training (like the hot tub or sauna) that acts as a missing link between theory and real-world proof.

The study found that 5 weeks of hot tub training increases hemoglobin mass and VO2 max, which coincides with improved running economy. WOW! We break it all down.

And this one was full of incredible topics! Topics: a...

We thought deeply about the societal implications of Paw Patrol before this amazing episode! The main science discussion involved a pair of strange, counter-intuitive wrinkles of physiology. The first was the sometimes paradoxical finding of higher hemoglobin A1c in many elite athletes. The second involved a new paper addressing a connection between suppressed thyroid hormones and low energy availability. 

Both phenomena demonstrate...

We chocolatized our life before this amazing episode! The main topic was a new study on elite marathoners measuring responses to different carb intakes, finding a 2.6% lower oxygen cost at 120 grams per hour compared to 60 grams per hour. It showed massive carb oxidation rates at high outputs. In 10 years, we might look back on this study as a game-changing moment in the science of endurance performance. 

And this one had so many co...

We stretched the ketones-as-robot-butt metaphor to its limits for this awesome episode! The main topic was a new study measuring fatigue resistance in marathons. Athletes completed lab tests prior to a marathon, with final results correlating with different attributes. Unfortunately, the athletes weren’t fueling during the protocol. What is this, 2005?! 

We broaden it out for conclusions that apply to everyone. Fatigue resistance wi...