Hey Performance Nerds! Jonah here. 🤓

99% of runners are chasing a bigger VO2 max, thinking it's the key to faster times. Not so fast.

Most races happen below your VO2 max. You’re building a Ferrari engine but only driving it at 75%.

Even elites don’t win on VO₂ max alone. Paula Radcliffe, British marathon icon, kept getting faster even though her VO₂ max stayed the same. Her edge?

She ran more efficiently—faster pace, same oxygen.

Today we're breaking down:

• 😱 Why your VO₂ max ceiling doesn’t dictate race pace

• 🤔 When VO₂ max actually matters (and when it doesn’t)

• ✅ A science-backed progression that actually works

• 📊 My go-to 6-week training block for aerobic upgrades

(Augie, my dog, still wants a Ferrari just to hang his tongue out the window at 100 mph.)

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Are You a True Running Nerd? Prove it.. 🧐

Welcome to the prove you’re a nerd section. Each week, I ask a question about a common running science myth.

Answer correctly, and you’ll be entered into a weekly raffle to win a package of Jonah’s favorite supplements.

Last Week’s Results: Sodium Science Unpacked 🧂💧

Heads up, hydration nerds—this one sparked a mini salt-storm. So let’s clear it up: I take electrolytes daily and recommend them to every athlete I coach. But during races? Timing is everything.

The correct answer?
C. When exercise exceeds 4 hours, it's hot, and you're replacing most of your sweat losses ✅

That’s where the science kicks in—specifically, from sodium researcher Alan McCubbin. His research shows that:

• For shorter events (like sub 3 marathons or soccer matches), sodium replacement isn’t necessary, even with high sweat rates.

• The body can maintain sodium levels naturally—especially if you're only replacing ~60–70% of your fluid losses.

• Sodium only becomes critical in ultra-long events where you’re drinking a lot and sweating buckets (think: 4+ hours in the heat). In those cases, failing to replace sodium could lead to hyponatremia (dangerously low blood sodium).

Vote Breakdown:
🟩 A. Any time you start sweating—even in short workouts – 118 votes
⬜️ B. Only during intense interval training sessions – 9 votes
🟨 C. When exercise exceeds 4 hours, it's hot you're replacing most of your sweat losses – 38 votes ✅
⬜️ D. Only if you have low sodium in your diet to begin with – 17 votes

Bottom line?
Electrolytes matter—a lot—but they’re not a magic bullet during every session. Use them daily for hydration habits and pre/post fueling. In racing, their performance impact shows up most during long, hot, high-fluid events. So don’t skip the sodium—but time it wisely. 💧🧠

Want the full geek-out? McCubbin’s research found that even in hot marathons, sodium isn’t required unless you're over-replacing fluid and sweating like crazy. Cramping? That’s usually about fitness, not salt.

Let’s science smarter—not salt harder. 🧂📊

Nerdy Finds of the Week 📚🧑‍🔬

This section includes my favorite research, podcasts or books about running/lifting science.

Research Review: Alan McCubbin’s Sodium Research

🔬 Core Finding

• Sodium replacement is only needed in ultra-endurance events if you’re drinking enough to replace 70%+ of sweat losses.

📊 Key Research Points

• Plasma sodium stayed stable in marathons—even with high sweat sodium and no sodium intake

• Hyponatremia risk only appeared when athletes drank too much (≥70% of sweat loss)

• In ultras, sodium balance held unless high fluid + high sweat sodium combined

• In a 5-hour heat trial, sodium boosted blood sodium but didn’t affect thirst, effort, or hydration

• Most athletes naturally drink ~70% of what they sweat—no matter the sodium

• Extra sodium didn’t reduce heat strain or improve body-water balance

• Large sodium deficits were handled by the kidneys post-exercise, not mid-race

🛠️ Practical Applications

• 🚫 Events under 4 hours ➔ No sodium needed, even in heat

• 🍽️ “Salt to taste” ➔ Sufficient for most non-ultra athletes

• ⚡ ≥70% fluid + high sweat sodium ➔ Add sodium to avoid low plasma sodium

• 🚫 <60% fluid replaced ➔ Sodium not needed, even in ultra events

• 🍽️ Personalized sweat testing ➔ Helps fine-tune sodium plan for races over 6 hours

• 🚫 Extra sodium ➔ No effect on thirst, fluid intake, or performance

• 🚫 Cramps ➔ Sodium doesn’t prevent them in most runners

🎯 Bottom Line

• Unless you're guzzling fluids and sweating salt, midrace sodium isn’t necessary

P.S. - We have a crew of 16,500+ nerds here who are running FAST using science.

Did you need running science advice or tips? 🏃‍♀️💨🧪

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