Everything You Know About Marathon Cramps is Wrong: 6 Ways to Stop Cramps From Destroying Your Marathon Time

Estimated read time: 3.42 minutes

Hey Performance Nerds! Jonah here. 🤓

Warning: Everything you think you know about cramps is probably wrong!

Most runners blame dehydration and electrolytes, but science tells a different story.

Let's break down what REALLY causes cramps and how to prevent them from ruining your next marathon.

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The Truth About Cramps (It's Not What You Think!)

Want to know a secret? Science says dehydration and electrolytes aren't the main villains behind your muscle cramps.

A shocking study of ultramarathon runners found:

• Cramping runners were MORE hydrated

• Electrolyte levels were the same in crampers and non-crampers

• The real culprit? Muscle fatigue and damage

What Actually Causes Marathon Cramps?

Muscle fatigue and damage are your biggest enemies (besides that guy telling you to go keto for a fast marathon 🙄).

Research shows cramping runners:

• Had more muscle damage before racing

• Trained twice as much in the final 3 days

• Started 13 minutes too fast

Think about it - cramps usually strike in the last 10K when fatigue peaks. Your body's way of saying "Yeah... that's gonna be a no from me." 🙅‍♂️

Heat Makes Everything Worse

While dehydration alone probably won't cause cramps, heat:

• Speeds up fatigue

• Increases muscle damage

• Makes your body work harder

6 Science-Backed Ways to Prevent Marathon Cramps

The key? Reduce physical and mental fatigue. Here's how:

1) Train Smart for Race Demands

• Build mileage and speed gradually

• Include marathon-pace runs (especially close to race)

• Practice in race conditions (heat, hills, fueling)

• Don't overtrain before race day

2) Nail Your Taper

• Travel early to adjust to time zones

• Cut volume but keep intensity:

  • 2 weeks out: 60-70% normal volume

  • 1 week out: 40-50%

  • Run the same number of days per week or reduce by 1-2 days

  • Keep marathon-pace work

3) Pacing Your Marathon

• Begin slightly below your goal pace

• Build speed based on feel, heart rate, and breathing

• Break your race into blocks:

  • Miles 1-13: 5-10 seconds below goal pace

  • Miles 13-20: Goal pace if feeling good

  • Miles 20-26: Push the pace

4) Beat the Heat 🌡️

Here's your science-backed plan to stay cool:

Before Race Day:

Train your body to handle heat (heat acclimatization):

• 🔥 Early Phase (>8 Weeks Out):

  • 10 days of heat exposure

  • Use active methods (exercise in heat) or passive methods (hot water immersion, sauna)

• 🔥 Pre-Comp (8–2 Weeks Out):

  • 2–3 heat exposures per week

  • Combine active and passive methods to maintain and build adaptations

• 🔥 Final Phase (2 Weeks to Race Day):

  • 1–2 passive heat exposures per week

  • Focus on sustaining adaptations without adding stress during taper

Race Morning:

• Pre-cool with an ice slushy drink or cold towel 30 minutes before starting

During Race:

• Drink cold fluids throughout as tolerated

• Splash cold water on your neck

• Slow down 10-15 seconds per mile based on heat

5) Build Strength

 💪 Strong muscles = less fatigue and damage.

Here's your plan:

• 2 weekly strength sessions

• Heavy weights (80% max) for 3-8 reps and Plyometrics

• Key exercises: Squats, Deadlifts, Single-leg exercises, Calf raises

Pro Tip: Pro Tip: Skip strength work before long runs or speedwork!

6) Fuel Like a Pro: Carbs

Warning: Your muscles need fuel (carbs) to prevent cramps!

Studies show that low glycogen increases muscle damage and fatigue, which can cause more cramps!

Keep Carb Levels High to Fuel Your Muscles:

Pre-Race Carb Loading:

• 8-12g carbs per kg bodyweight for 1-2 days before

• 150lb runner: 600-900g carbs daily

Pre-Race Meal

• 2-4 grams of carbs per kilogram of body weight 2-4 hours before the race

• Aim for a 2:1 glucose-to-fructose carb ratio

  • Example: 67g glucose + 33g fructose for 100g total carbs

Race Day Strategy:

• 60-90g carbs per hour

• Start at mile 1

• Mix glucose/fructose sources

• Practice in training

Practical Summary

• Cramps are mainly caused by fatigue and muscle damage, not dehydration

To Prevent Cramps:

• Train Smart

  • Include marathon-specific runs

  • Increase intensity as race approaches

  • Do 2 strength sessions per week

• Nail Your Taper

  • Cut volume 2 weeks before race

  • Keep some intensity

  • Prioritize sleep and recovery

  • Carb Load 1-2 days before your race

• Race Strategy

  • Start below goal pace

  • Build speed based on feel

  • Fuel with 60-90g carbs per hour

  • Start fueling at mile 1!

#1 Carb Load Mistake Marathon Runners Make

Did you miss my video about #1 Carb Load Mistake Marathon Runners Make? You can find it below!

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Don’t forget: You + Science = AWESOMENESS 😎

Yours in science,

Jonah

Please email me directly if you’re interested in references for this week!