Hello Runner,
Welcome back to your weekly moment of endurance nutrition!
Happy Weekend!
How was your week?
My week was pretty normal.
It started great because last weekend I actually rested, which I rarely do. I rested so much that I ended up with a sore back, hahaha.
I always say I’m going to rest, but I always end up doing a bunch of things. This time, I let myself.
During the week, I kept up with my workouts. I didn’t go to the track on Wednesday, but I went out for a run on the street, and it went really well.
Thursday was Valentine’s Day here in Barcelona, which they call Sant Jordi (the patron saint of Catalonia). I love this day because the city is filled with roses. Store windows and classic buildings are decorated with red roses, and the city is filled with stalls selling flowers and books. It’s the most beautiful thing.
Other than that, I worked more than I studied.
Today’s topic is muscle cramps. It’s a pain that affects many runners, especially those with a high training volume, as well as those who run marathons, ultramarathons, and triathlons.
In addition, it’s a topic that’s rarely discussed, and most people still believe that eating a banana will cure a cramp.
I’ll share what science has to say on this topic and what actually works to prevent this pain.
What Really Causes Cramps While Running?
Current science points to two key factors working together:
1. Muscle Fatigue (the main driver)
When muscles become overly fatigued, the signals between your nerves and muscles get disrupted. This can cause the muscle to contract involuntarily, which you feel as a cramp.
This is why cramps are more common:
Late in long runs or races -> kilometer 30-35 of a marathon, ultramarathon, and triathlon.
When you increase intensity too quickly
When you’re undertrained for the effort
When you're dealing with accumulated fatigue
When you have a history of cramps
When the training cycle is incompatible with the demands of the race
2. Hydration & Electrolytes (important, but secondary)
Electrolytes like sodium, potassium, magnesium, and calcium help regulate muscle contractions and nerve signals.
When you sweat, you lose these minerals, especially sodium.
But here’s the key insight:
- Electrolyte loss doesn’t usually cause cramps on its own
- It can make your muscles more vulnerable to cramping when fatigue sets in
Also, current research shows that sodium supplementation does not guarantee the prevention of cramps.
Despite these two important points, muscle cramps have multiple causes. There may be 4, 5, or even 6 causes.
Understanding this will give you a more comprehensive perspective on your workouts, your pace, your diet, and so on.
So, what should be done?
It depends. If the main cause is neuromuscular fatigue and the runner is properly fueled and hydrated, adjustments should be made in consultation with a coach or physical education professional. They should ensure an appropriate progression in volume and intensity and prescribe muscle-strengthening sessions.
Now, if even with neuromuscular fatigue, that runner isn’t properly hydrated or fueled, nutritional adjustments should be made.
STRATEGIES
Smart Nutrition Strategies That Actually Help
Let’s focus on what the evidence supports, and what you can apply right away.
Stay Hydrated, But Don’t Overdo It
More water isn’t always better. Drinking too much plain water can dilute sodium levels and actually increase risk.
What to do:
Drink to thirst for most runs
For longer runs (>60–90 minutes), include electrolytes
Prioritize Sodium (Your #1 Electrolyte)
Sodium is the main electrolyte lost in sweat — and the most important for maintaining fluid balance and nerve function.
General guideline:
~300–600 mg sodium per hour during long runs
More if you’re a heavy or salty sweater
Carbs: The Overlooked Anti-Cramp Tool
Because fatigue is the main cause, anything that delays fatigue helps reduce cramps.
That’s where carbohydrates come in!
During longer runs (>60 min):
Aim for 30–60g carbs per hour
This helps maintain muscle function and control
Long-Term Prevention
The most effective way to reduce cramps is to be consistent across habits.
Build resilience through:
Gradual training progression
Practicing race nutrition in training
Pacing appropriately early in runs
Strength training (especially for commonly cramping muscles)
Cramps are a signal that your muscles are reaching their limits, and your system needs better support.
Each case must be evaluated individually to determine what needs to be done to relieve the cramps.
If you frequently experience cramps during long runs, consult a professional to find out what can be done.
Product of the Week
This week's Product of the Week is the Xtratus NEUTRAL Carbohydrate and Electrolyte Mix.
This drink mix is a great option for long runs, especially for those who can’t tolerate carb gels.
It has a neutral flavor, allows you to consume up to 90g of carbs per hour, and contains a good amount of electrolytes.
Plus, it’s gut-friendly, which is super important. Even so, you still need to train your gut before any race.
Since I’m a partner with Xtratus, they gave me a discount coupon to share with my clients and readers. Coupon: ANAPAULAALONSO10
Track of the Week 🎧️
This week's Track of the Week is a song I discovered recently, and I thought was perfect for running in Z4 or Z5. It’s great for matching your stride to the beat.
I’ve chosen Luz by The Chronics
Any questions or something you would like to share, drop me an email
Wishing you a great weekend and week ahead!
Here’s to health and good runs⚡️
Ana Paula Alonso