About two years ago, I went to see my doctor. Our conversation went like this:
Doctor: “Bill, you need to lose weight.”
Me: “I know, I know. How much do you think I need to lose?”
Doctor: “That depends. How long do you want to live?”
Funny guy, huh? But that one landed, and it marked a turning point. Since then, I’ve made health and fitness a genuine priority in ways I hadn’t since at least before the pandemic.
Slowly but surely, it’s added up. One extra dividend I hadn’t planned on: I’ve had my best ski season since I was a kid. The days on the mountain feel noticeably better than they did when I started.
I assumed that was just the result of being in better shape overall.
A new study suggests, however, something more specific might also be happening in my head. It might give you a new perspective on exercise too.
What the research found
Writing in the journal Brain Research last month, researchers from University College London say they found that the brain benefits from exercise don’t just accumulate; instead, they actually compound as you get fitter.
Led by Flaminia Ronca of UCL’s Institute of Sport, Exercise & Health, the researchers took a group of sedentary, unfit adults and put them through a 12-week cycling program — three sessions per week. At the start, middle, and end of the study, they measured participants’ levels of a protein called BDNF, or brain-derived neurotrophic factor.
BDNF is sometimes described as the brain’s fertilizer. It supports the growth of new neurons and new connections between brain cells. It helps maintain the ones already there.
Exercise is one of the most reliable ways to trigger its release, as little as 15 minutes of moderate to vigorous aerobic activity appears to be enough to get it going.
The crux of the study: Resting BDNF levels didn’t meaningfully change over the 12 weeks. However, the spike of BDNF that followed a single hard workout got significantly larger as participants got fitter.
That increase tracked directly with improvements in aerobic fitness.
Thus, the fitter they became, the bigger the neurological response to each individual session.
On top of that, higher BDNF responses were linked to measurably better activity in the prefrontal cortex — the region that governs attention, decision-making, and self-control — during cognitive tests.
“The most exciting finding from our study is that if we become fitter, our brains benefit even more from a single session of exercise, and this can change in only six weeks,” Ronca said in a press statement.
The compound interest of fitness
People tend to think of a skipped workout as losing one unit of benefit, but this research suggests the math might be less forgiving than that.
What you’re also skipping is an opportunity to build the system that makes the next workout pay more.
Frankly, it also comports with my own experience, and I suspect anyone else who has gone from a “know I should” attitude to a “really hate to miss it” attitude at the gym.
There are some caveats, as always.
Only around 20 participants completed all the required sessions with usable data, which is a small sample. The results show correlation, not proof of causation.
So, treat this as a compelling early signal, not a settled verdict. Larger trials would help.
But, it fits a broader pattern in the research: The adult brain is more adaptable than most people assume, and the habits that support it tend to reward consistency in ways that aren’t always obvious in the short term.
Next up: a study on whether having a doctor with a deadpan sense of humor motivates people to be healthier.
At least it worked for me.
Other things worth knowing …
President Trump refused to apologize to Pope Leo XIV on Monday after criticizing the pontiff for his opposition to the war in Iran — and he sought to explain away his now-deleted social media post depicting himself as Jesus by saying he had thought the image was of him as a doctor. (AP; screen capture of the deleted post, so you can decide)
President Trump’s decision to blockade all Iranian shipments out of or into the Strait of Hormuz starting Monday morning sets up the next great test in the Iran war: Which side can endure more economic pain, Tehran’s new leadership or Mr. Trump himself? Almost everything about how this new turn in the war plays out is likely to look very different than what has unfolded so far. (NYT)
Rep. Eric Swalwell, a former Democratic frontrunner in the California gubernatorial race, resigned from Congress on Monday amid sexual misconduct allegations. Swalwell announced his resignation in a statement posted to his X account, while still denying some of the allegations made against him in recent days. (CNBC)
It will be more expensive than ever to attend World Cup matches held in the United States this summer, a trend that has soccer fans in the U.S. and around the world frustrated about who will have access to watch historic clashes on the pitch in person. The 1994 World Cup in the U.S. still holds the record for largest total attendance and average attendance per match. (The Hill)
So Much for Springtime: The East Coast Braces for Summer Heat: Washington could hit 90 or higher. New York won’t be far behind. But it won’t last long. (NYT)
Surcharges Are Suddenly Everywhere—And Grumpy Americans Are Paying Up: The add-ons were a feature during Covid and are once again sneaking their way onto bills. ‘I feel like I need to be my own detective.’ (WSJ)
Wearing formal office wear, reading glasses and leather shoes, an annoyed Philippine President Ferdinand Marcos Jr. did a few rounds of jumping jacks and jogged briefly outside his office in front of journalists Monday to disprove rumors of his failing health. “I challenge anyone who are saying that I am sick, that they come and exercise with me,” Marcos, 68, told reporters. “You come to the gym with me. Let’s see who can lift the weights better.” (AP)
Thanks for reading. Photo by Stefano Romanello on Unsplash. I wrote about some of this before at Inc.com. See you in the comments.