When you hit the wall at mile 19 of a marathon (or mile 80 of a 100-miler) it feels like your body is the problem. Your legs are concrete, your stomach is in revolt, and the finish line might as well be on the moon. But what if the wall is mostly in your head?

Emily Balcetis is a social psychologist who studies how vision and perception shape motivation: how what people literally see changes what they believe they can do. She runs the SPAM Lab at NYU and is the author of Clearer, Closer, Better: How Successful People See the World. Her TED Talk on why some people find exercise harder than others has been viewed over a million times.

Zoë and Brendan get into why highly motivated runners literally see the finish line as closer than it is, how Joan Benoit Samuelson used a woman in pink shorts to win the first Olympic women's marathon in 1984, and why the wall is a psychological phenomenon rather than a physiological one. Emily explains why willpower isn't a fixed trait you either have or don't, the "if-then" framework she calls foreshadowing failure, and how negativity bias means our brains lie to us about our own progress, which is why becoming your own accountant might be more useful than another motivational Post-it on the bathroom mirror. Plus: how Emily decided to learn the drums in a one-bedroom Manhattan apartment, and what it taught her about tracking the kind of progress the brain can't see.

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The featured race is the Haul Ass Ultra Running Festival, Saturday, June 6th, in Erie, Colorado. Eight distances on the menu — a 50-miler, 50K, 10K, 5K, and 3-, 6-, 9-, and 12-hour timed events — which means whatever shape you're in and whoever you're bringing along, there's a way to make it work. Sign up at UltraSignup.com.

The Trailhead is part of the UltraSignup Podcast Network.

David Raichlen is a professor of biological sciences at the University of Southern California whose research examines how human evolution, physical activity, and brain health are linked across the lifespan. In this conversation, Zoë and Brendan talk with David about what's actually happening in your brain when you go from couch to consistently active, why exercise might be the closest thing we have to a dementia preventative, and why his research on the runner's high, which famously involved humans, dogs, and ferrets, suggests it evolved as something more useful than feeling good.

They also get into what hunter-gatherers like the Hadza can (and can't) tell us about how to live, why "more is better" hits diminishing returns at the high end, the trouble with paleo prescriptions, and whether sitting really is the new smoking. Plus: Brendan tries to figure out if his rock-climbing mom or his golfing dad is doing better cognitive work than he is.

This episode is brought to you by Running Warehouse, the one-stop shop for all things trail running, with gear guides and expert resources to help you figure out what actually works for you. Use code TRAILHEAD for free two-day shipping on orders over $50.

Our featured race is the Sonoma Fall Classic, the inaugural fall festival in the heart of California wine country featuring a 100-miler, the original Lake Sonoma 50 returning to its 2008 point-to-point roots from South Lake Trailhead, a trail marathon, and four-person relays. Sixteen miles of buttery single track, sweeping lake views, swimmable water crossings, and free on-site camping. Registration closes Monday, October 12. Sign up at UltraSignup.com.

The Trailhead is part of the UltraSignup Podcast Network.

Rochelle Bilow is a romance novelist, food writer, French Culinary Institute graduate, former Bon Appétit editor, and current kitchen gear expert at Serious Eats, and she just came back to ultrarunning after nearly a decade away from the sport. In this conversation, Zoë and Brendan talk with Rochelle about what she learned cooking on a farm that culinary school never taught her, why she pivoted from heartbreak memoir to romance fiction, and what it's like to balance writing deadlines with ultra training (her answer: ask for a deadline extension).

They dig into why romance as a genre gets unfairly dismissed, what makes a great enemies-to-lovers arc, and the trail running romance novel she's currently writing. Plus: the $400 toaster that changed Rochelle's life, the truth about toaster oven air fryers, and the only correct way to clean a cloudy Vitamix.

This episode is brought to you by LMNT. Stay on top of your electrolytes all day, not just on the run. Grab a free sample pack with any order at drinklmnt.com/UltraSignup.

Featured Race: Booneville Backroads Ultra — 10K to 100 miles through the Bridges of Madison County countryside in rural Iowa. New for 2026: a fully marked course and crew support allowed. Trail Sisters members can DM the race for a discount code. Race day is September 5th, registration closes August 28th. Sign up at UltraSignup.com.

The Trailhead is part of the UltraSignup Podcast Network.