For years, endurance athletes have searched for safe, legal ways to squeeze out those extra seconds when it matters most. One of the lesser-known — but scientifically supported — options is sodium bicarbonate, more commonly known as baking soda.
Before you go raiding your pantry, here’s what runners need to know about using bicarbonate as a performance supplement.
What Is Sodium Bicarbonate?
Sodium bicarbonate is a naturally occurring compound that acts as a buffer in your body. During hard running — think 800m repeats, a 5K race, or a brutal hill workout — your muscles produce hydrogen ions that make your muscles acidic.
That acidity is one of the main reasons your legs start to burn and your pace slows. Sodium bicarbonate helps neutralize that acidity, letting you sustain high-intensity efforts for longer.
How It Works
- Without bicarbonate: As you run hard, hydrogen ions build up, lowering muscle pH → fatigue sets in sooner.
- With bicarbonate: The extra bicarbonate in your bloodstream soaks up those hydrogen ions, helping you maintain performance longer before fatigue.
It’s a bit like having a bigger fuel tank — but for your muscles’ ability to handle lactic acid.
When It Helps Most
Bicarbonate is most effective for events or workouts in the 1–10 minute range, where muscle acidosis is a major limiter. Examples:
- Middle-distance track events (800m, 1500m, mile)
- VO₂ max intervals
- CrossFit-style or mixed-intensity races
- Hill repeats
It’s less useful for steady marathon pace or ultra-distance runs, where fatigue is driven by other factors.
How to Take It
The classic research-backed dose is:
0.3 grams per kilogram of body weight
(≈ 21 grams for a 70 kg / 154 lb runner)
This is typically mixed into water or juice and consumed 60–90 minutes before your workout or race.
⚠️ The Big Caveat: GI Distress
The most common side effect? Stomach cramps, nausea, diarrhea — the last thing you want before a race.
Tips to Reduce Side Effects
- Start Small: Try 0.1–0.2 g/kg first to see how your stomach reacts.
- Spread the Dose: Split into smaller amounts over 30–60 minutes instead of taking it all at once.
- Take With Food: A light carb-rich snack can help buffer the supplement itself.
- Test in Training: Never experiment on race day. Find your personal tolerance in workouts first.
- Consider “Microdosing”: Some athletes take smaller amounts daily for several days before competition rather than one big dose.
Is It Legal?
Yes — sodium bicarbonate is legal under World Anti-Doping Agency (WADA) rules. It’s a natural substance your body already produces.
Who Should Avoid It?
- Athletes with hypertension or sodium-sensitive health conditions (it’s high in sodium)
- Anyone with a history of severe GI issues during exercise
- Runners who haven’t tested their tolerance in training
Bottom Line
Bicarbonate isn’t a magic bullet, but it’s one of the most scientifically supported, inexpensive, and legal supplements for short-to-mid-distance performance. If you tolerate it well, it could give you that extra edge in training and racing — but it’s crucial to test it well before competition.
Quick Takeaway
- What it does: Buffers muscle acidity so you can go harder for longer
- Best for: Efforts 1–10 minutes in duration
- Dosage: ~0.3 g/kg body weight 60–90 min pre-exercise
- Watch out for: Stomach issues — test in training first