I Got Faster After 40. The Science Says That’s Possible—But Not Because Aging Reversed.

There’s a story I tell that sounds like it’s trying to pick a fight with biology.

My first marathon was at 30: 3:59.

My second marathon was at 40: 3:33.

My best marathon so far was at 44: 3:31.

On the surface, that looks like I’m “counter-trending.” Like I discovered the rare anti-aging cheat code hidden behind an airport lounge.

Reality is less dramatic (and more useful): I didn’t get younger. I got better.

And the most interesting part is this: the research doesn’t disagree with my timeline. It explains it.

The proof: a 47-year study that doesn’t care about my feelings

A Swedish research team followed 427 people (48% women), repeatedly testing them from age 16 to 63. Same humans. Nearly five decades. That’s the kind of dataset you don’t argue with—you listen. 

They measured:

• Max aerobic capacity (cardiorespiratory fitness)
• Muscular endurance (bench press reps)
• Muscle power (jump test)

The headline finding is blunt:

Aerobic capacity and muscular endurance peaked around ages 26–36, then declined—slow at first, faster later. 

From peak to age 63, the average decline across outcomes was roughly 30% to 48%. 

So… if peak capacity happens earlier, why did my marathon times improve into my 40s?

Because marathon performance ≠ raw capacity alone.

Two forces were fighting inside my results

Think of performance as the product of two curves:

Curve A: Biology (the ceiling slowly comes down)

The study shows average physical capacity starts declining before 40, and the decline accelerates later. 

A separate longitudinal study on peak VO₂ found the decline accelerates with each decade, even when people are active (activity raises the baseline, but doesn’t stop time). 

Curve B: Training age (your execution gets smarter)

Marathons reward experience like a cruel professor:

• pacing
• fueling
• durability
• better training structure
• fewer “rookie errors” that cost minutes

So if you improve execution faster than biology declines, performance can still rise for years—even decades.

That’s what my timeline likely reflects: I didn’t break aging. I reduced waste.

The real “secret” in the Swedish study: the gap gets huge

The most WbMT-friendly detail wasn’t the average decline. It was the exploding variance.

As people aged, the difference between the strongest and weakest performers widened dramatically—up to 25-fold variance in relative aerobic capacity by age 63. 

Translation: aging is real, but how you age becomes increasingly negotiable.

That’s why my story belongs in this blog: it’s not “look at me.” It’s “look at the leverage.”

The honest part: I probably left speed on the table

Here’s the inconvenient truth I’m willing to say out loud:

I improved while still being less disciplined than I could have been.

Which means the real lesson isn’t “you can improve after 40.”

The real lesson is:

If you build capacity earlier, you carry more into later decades.

The study itself makes a similar point: physical activity is linked to higher performance across outcomes, and becoming active later still helps—suggesting the door doesn’t close, but earlier habits compound. 

My “Story + Proof” training takeaways for busy travelers

This is the system I wish I’d run sooner—because it’s robust to travel chaos and doesn’t rely on perfect weeks.

1) Strength training isn’t optional after 35

A meta-analysis found any resistance training was associated with lower all-cause mortality, with the biggest reduction around ~60 minutes/week (diminishing returns beyond that). 

That’s a shockingly low bar for a huge payoff.

Travel-proof version: 2×30 minutes/week. Hotel gym. Basics. Done.

2) Variety beats “one perfect routine”

A large cohort analysis in BMJ Medicine found higher physical activity variety was associated with lower mortality, independent of total activity level. 

That matters when travel nukes your normal plan.

Translation: if you can’t run, incline walk. If you can’t lift, do loaded carries. If you can’t do long sessions, do short ones often.

3) Anchor to guidelines, then personalize

WHO’s adult baseline: 150–300 min/week moderate (or 75–150 vigorous) plus strength work 2+ days/week. 

That’s not a performance plan, but it’s a reality check: you don’t need heroic complexity to protect your future self.

The punchline (and the point of WbMT)

My marathon PR at 44 didn’t mean aging paused.

It meant my training finally started paying rent.

Age nudges the ceiling down. Training raises the floor—and often raises the whole house.

The Swedish data says decline starts earlier than most people assume.

My data says improvement can still happen later than most people expect.

Put them together and you get the real strategy:

Start building capacity now—because later you’ll spend it.