The Top Ten Sweat Science Articles of 2025

A look back at which sports science topics made headlines this year.

‘Tis the season for introspection (or, if you prefer, navel-gazing). This year was notable for me because I finally published the book I’d spent the previous five years working on, The Explorer’s Gene. The book is about why we’re drawn to new horizons and fresh challenges, what we get out of it, and how to balance that urge with the desire to stick with what’s familiar. On the surface, it seems like a big swerve away from the “science of endurance and fitness” themes I mostly focus on.

In reality, The Explorer’s Gene grew directly from my previous book, Endure. In the latter, I was interested in how we push our limits; in the former, I’m grappling with why. There are some endurance-specific stories in there: speedskater Nils van der Poel’s decision to overhaul his training in what I called “one of the most radically unconventional experiments in the annals of Olympic sport”; the mythologist’s Joseph Campbell’s little-known career as one of the top half-milers in the world, hero of the 1926 Penn Relays and just a second off the world record at the time. But I’ve been pleased to hear from longtime readers that they also see the more subtle underlying connections between the themes of exploration and endurance.

If you haven’t had a chance to read it yet, I hope you’ll check it out! It’s currently 44 percent off on Amazon.com (just $18), available at local bookstores everywhere, and you can find links to other retailers around the world here. Thank you for supporting my work.

The Top Ten!

On a semi-related note, the end of the year is also a time when I take a look back at the topics I’ve covered in my Sweat Science column for Outside. I write four columns a month, which means I end up covering a surprisingly wide range of topics (you can scroll through the whole list here). I don’t ask for or receive any data on which articles attract the most readers—I worry that checking that data will tempt me to start writing more for clicks rather than following what seems interesting to me. But at the end of each year, I do ask what the ten most-read articles were. It’s rarely the ones I would have predicted! Here’s that list for 2025:

#10: The 2025 Sweat Science Summer Book List

A selection of (mostly) new titles for fans of science, endurance, fitness, and adventure

#9: What an ‘Alone’ Fan Learned Backpacking in ‘Alone’ Country

The North Coast Trail, on Vancouver Island, takes you deep into the territory where several seasons of the reality show were set

#8: Does Exercise Really Benefit Your Mental Health?

Scientists take a closer look at the studies supporting links between physical activity and mental health and ask: is the evidence any good?

#7: Here’s Exactly What It Takes to Run—And Then Recover From—100 Miles

Physiologists track the calories burned and fluids consumed during a mountain ultra

#6: How Many Carbs Do You Really Need to Maximize Endurance?

It’s either way more than you think or way less than you think, depending on which scientists you listen to

#5: Puma’s High-Tech New Supershoe is Here—and It’s Already Turning Heads

The Fast-R Nitro Elite 3 claims to offer the biggest improvements in running economy since the Nike Vaporfly took the world by storm eight years ago.

#4: Why Athletes Should Think Twice About Vitamin D Supplements

A new study finds athletes with higher vitamin D levels are stronger, but the big picture remains murky

#3: Why Increasing Your VO2 Max Might Boost Your Brain

Two new studies add fresh data to the debate about exercise and brain function

#2: Why Steeper Is Cheaper for Climbing Hills

New data suggests that the most efficient uphill slope is steeper than you think

#1: How to Train Your Physiological Resilience

Scientists tackle the challenge of maintaining qualities like high VO2 max and good running economy even when you’re tired

Thanks, once again, for reading and supporting my work – I’m hugely grateful, and I’m looking forward to digging back in for 2026. But first, the holidays: here’s hoping you have a restful and enjoyable season.

Alex Hutchinson