Why Baking Soda Could Help You Surge at Mile 20—Or Ruin Your Race by Mile 5
Estimated read time: 4.1 minutes (about as long as it takes to talk yourself out of that final tempo rep 🤔)
Hey Performance Nerds! Jonah here. 🤓
This supplement can help you surge at mile 20 in a marathon.
It can also end your race before mile 5.
Elite marathoners are using sodium bicarbonate to buffer fatigue during their hardest efforts. The science is solid. Using it wrong is where things go sideways.
Here’s what you’ll learn today:
How bicarbonate actually buffers fatigue (hint: it's not about lactate)
Who benefits most, and who should skip it
The exact protocol to test it without destroying your gut
When it matters in a marathon and when it's just expensive baking soda
(Augie thinks I'm overthinking this. He's never bonked on a long run, but he's also never had to find a bathroom at mile 18.)
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🧬 Performance Sponsors:
🚀 Train Harder. Recover Smarter.
SiS—the same science-backed fuel trusted by Olympic marathoners—is now sponsoring Marathon Science.
From gels to recovery tools, every product is backed by real performance data and built for serious athletes like you.
🚀 Power Your Pace with Stryd
Stryd — the running power meter trusted by serious athletes — is now an official performance sponsor of Marathon Science, delivering real-time pacing precision so you can train smarter and race faster.
💡 See this week’s full Stryd training tip at the end of this newsletter.
🧬 The Science: How Bicarbonate Actually Works
Your body already has a built-in buffering system.
During high-intensity exercise, rapid ATP production increases hydrogen ions (H⁺) and lactate inside your muscles.
The “burn” comes from H⁺ accumulation, which increases acidity and interferes with muscle contraction.
Your blood’s natural bicarbonate buffers those H⁺ ions, converting them to CO₂, which you breathe out.
Supplementing bicarbonate boosts this system. More buffer means faster acid clearance from your muscles.
By pulling acidity out of the muscle, bicarbonate helps hard efforts stay sustainable longer before fatigue forces a slowdown.
Lactate isn’t the problem. Lactate is actually a fuel your muscles use.
Blood lactate often goes up after taking bicarb because buffering helps pull H⁺ and lactate out of your muscle cells faster.
Marathon takeaway: acidity becomes limiting above your second threshold.
Think surges, hills, and fast finishes, not steady aerobic cruising.
If your marathon plan is steady, sub-threshold cruising from start to finish, acidosis usually isn't your bottleneck.
⚙️ What Supplementing Bicarbonate Changes
Extracellular buffering gets a boost.
Supplementing raises blood pH and bicarbonate concentration. Think of it like steepening a drainage gradient: H⁺ gets pulled out of muscle cells faster.
Perceived effort may drop.
At moderate intensities (marathon pace), some athletes report a given pace feels easier, helping them hold effort when fatigue would normally force a slowdown.
Others feel nothing.
The GI risk is real.
When bicarbonate hits stomach acid, it produces CO₂ gas.
That rapid CO₂ expansion causes bloating, cramping, and sometimes worse. This is why so many athletes have horror stories.
Newer delivery systems help. Hydrogel-encapsulated forms reduce GI risk.
You still need to test before race day.
🎯 Who Bicarbonate Helps (and Who It Doesn’t)
Think of this as a “should I even consider this?” filter.
Scenario | Likely Benefit | Notes |
|---|---|---|
Hilly courses or fast finishes | Higher | Repeated efforts above threshold |
Negative split racing | Higher | Late-race acidosis more likely |
Tactical races with surges | Higher | Anaerobic capacity matters |
Steady sub-threshold pacing | Lower | Acidosis rarely limiting |
“Just finish” Zone 1–2 pacing | Minimal | Fueling and durability matter more |
History of GI issues | Caution | Testing required |
Sodium sensitivity or hypertension | Avoid | Sodium load is meaningful |
Unwilling to test in training | Avoid | Never debut on race day |
Truth: if most of your racing lives in low to moderate zones, fueling and durability will move the needle more than bicarbonate.
🔧 The Practical Protocol
Dose:
0.3 g/kg bodyweight is the classic research standard
0.2 g/kg bodyweight may offer similar benefits with lower GI risk
Higher doses increase GI risk without proportional gain
Example: a 70 kg runner = 14–21 g bicarb
Timing:
Blood bicarbonate typically peaks 60-90 minutes after ingestion, but there's individual variability.
Take it 90-120 minutes before your race or hard session to give yourself a buffer (pun intended).
Timing Test Framework:
Test different timing windows in training to find your personal sweet spot.
Test Session | Timing Before Hard Effort | What to Track |
|---|---|---|
Test 1 | 60 minutes | GI symptoms, perceived effort, performance |
Test 2 | 90 minutes | GI symptoms, perceived effort, performance |
Test 3 | 120 minutes | GI symptoms, perceived effort, performance |
Run a similar intensity session each time. Note which timing gives you the cleanest gut and best feel.
GI Risk Reduction Checklist:
[ ] Use hydrogel delivery if available (dramatically reduces GI risk)
[ ] If using powder/capsules, split into 3-4 mini-doses over 30 minutes
[ ] Take with familiar carbohydrates and fluids
[ ] Test under race-like conditions (not just easy runs)
[ ] Never debut on race day
Abort rule: if GI distress shows up in testing, that’s your answer. Better to know now than at mile 5.
🏃♂️ Using Bicarbonate in a Marathon Context
It's not just for race day. It can help in training too.
Track workouts. Threshold intervals. VO₂ max sessions. Anything above your second threshold is fair game.
The logic: if bicarb helps you tolerate more reps at higher intensity, you get more quality stimulus. More stimulus, better adaptations.
Use it max once or twice per week, reserved for your hardest sessions.
Where it matters in a race
Hilly courses
Late-race surges after hours of running
The final push when your legs want to quit
The benefit comes from tolerating harder efforts.
What it won't fix:
Pacing mistakes. Fueling gaps. Undertrained durability.
Sodium note
A 20 g dose carries a substantial sodium load. If you’re sodium-sensitive or have blood pressure concerns, talk with a physician first.
⚡ Practical Takeaways
Bicarbonate is a legitimate ergogenic aid, not bro-science
Steady cruising sees little payoff
Marathon benefits are situational, hills, surges, and fast finishes
GI distress is the limiting factor, hydrogel helps but doesn’t guarantee tolerance
Dose at 0.2–0.3 g/kg, 90–120 minutes pre-effort
Never use it without structured testing
Fueling, pacing, and durability still matter more
💬 One last thing before you go.
After the NFL, I wasn’t sure obsessing over performance science still mattered until I started helping this community.
Your training goals brought that fire back.
If you’re stuck, second-guessing something, or want to share how training’s going, hit reply. I read every message.
— Jonah
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.
Besides supporting muscle protein synthesis and limiting muscle breakdown, what’s the most overlooked reason endurance runners need adequate protein during heavy training blocks?
- A. Improving satiety so it’s easier to hit high daily calorie needs 🍽️🙂
- B. Supporting immune function when training stress is high 🛡️🤧
- C. Providing the amino acids needed to support mitochondrial protein synthesis and aerobic enzyme production 🧬⚙️
- D. Stabilizing blood sugar between long or double-session days 🔄🍚
Last Week’s Results: Fast Fuel Wins 🥖⚡
Most of you were dead on here, when the gun goes off, digestion speed matters more than how “balanced” the meal looks.
The correct answer?
A. Fat slows gastric emptying, delaying carb absorption when you need fast-access fuel ⏳🍞 ✅
Fat is calorie-dense and slow to clear the stomach. On race morning, that means carbs sit in line longer before they can hit the bloodstream and top up blood glucose. When intensity is high from mile one, delayed carb availability raises GI risk and can make early miles feel harder than they should.
Here’s how the votes shook out:
🟩 A. Fat slows gastric emptying, delaying carb absorption when you need fast-access fuel ⏳🍞 – 227 ✅
⬜️ B. Fat lowers your blood glucose, preventing early-race spikes and crashes 📉🥑 – 6
⬜️ C. Fat increases muscle damage during long runs, making late miles harder 🦵⚡ – 0
⬜️ D. Fat reduces sweat rate, helping you conserve electrolytes for later 💧🧂 – 0
Bottom line?
Race morning is about speed of fuel, not staying power. Keep fat low so carbs get in fast, your gut stays calm, and your legs get what they need when the pace is hot.
🏃♂️ Stryd Training Tip — Find Where You Fade with the Power-Duration Curve
Ever feel like your races are harder than expected, even when training has gone well?
The answer may sit in your power-duration curve.
Your power-duration curve shows your highest sustained power across durations, based on recent best efforts. It reveals not just how fit you are, but where fatigue starts to win.
Steeper curves produce strong short-duration power but fade faster as fatigue builds.
Flatter curves resist fatigue longer but often lack top-end power.
The most actionable insight is Actual vs Modeled.
Toggle Modeled Ability on in Stryd. If your Actual curve consistently sits below the Modeled curve in a specific duration band, and that range has been tested recently, that gap is a training target.
This is how to use the curve correctly: Find where your goal race sits. Train the part of the curve that doesn’t match.
💡 Bottom line: Your curve doesn’t define your limits. It shows you where fatigue is deciding your race.
Please email me directly if you’re interested in references for this week!