Every runner has a story of the run that almost ended them. Mine? It involved heat, a long route, and a handful of innocent-looking pitted dates.
I was trying to fuel naturally—something light, portable, and carb-rich. Dates had served me well before. But on this scorching summer run, they morphed into gut grenades. Within minutes, I was battling nausea, cramping, and the overwhelming urge to either lie down or teleport home.
Lesson learned: Heat changes everything.
☀️ The Heat Is a Multiplier
When temperatures rise, your body shifts blood flow to your skin to stay cool. That means less blood going to your gut, which slows digestion and makes fuel sit heavy. What works in spring can wreck you in July.
Your gut, like your legs, has to be trained for the conditions. And heat? That’s a whole other training block.
🤮 The Date Incident: A Sticky Situation
In cooler weather, dates were my go-to. Chewy, sweet, and easy to pack. But that day, they turned into sugary sludge, sitting like cement in my stomach.
“In cooler temps, dates are nature’s candy. In the heat, they’re belly bricks.”
My effort skyrocketed. Breathing got laboured. I felt like I was running on molasses—and not just metaphorically.
🌙 Fueling Adjustments for Hot Weather
When the heat is on:
- ❌ Skip high-fiber solids like dates, bananas, or trail mix
- ✅ Opt for liquid or semi-liquid fuels (e.g., Maurten, diluted gels)
- ⏰ Take smaller doses more often (every 15–20 minutes)
- ☕ Reduce caffeine if you’re heat-sensitive
And hydration? It needs to be strategic:
- Add electrolytes (like Nuun or SaltStick)
- Preload with sodium on extra-hot days
- Sip consistently, don’t chug
📈 Adapt Like a Pro: Heat Acclimation Tips
Don’t just run through the heat—train with it:
- Begin with short sessions in warm conditions
- Run in the shade or early morning
- Use heat as Zone 2 training: slower pace, same HR
- Monitor HR drift and hydration loss over time
As your body adapts, your sweat rate changes, your core temp stabilizes faster, and your GI system becomes less reactive.
🥬 Summer-Friendly Fuel Alternatives
If dates are off the menu on hot days, try:
- Maurten Drink Mix (cool, smooth, carb-dense)
- Gels designed for heat (minimal residue, low fiber)
- Frozen grapes or watermelon chunks (for shorter runs)
- Maple syrup pouches (bonus: Canadian cred!)
🔗 Internal Links
- This lesson came full circle on my June 29 long run…
- Learn more about my fueling strategy here.
- Monitoring Pa:HR in the heat is even more critical—see how I test my aerobic efficiency here.
🧠 Final Thought: Train the Gut, Trust the Process
Heat training isn’t just about surviving the temperature—it’s about teaching your body to handle the dual demands of cooling down and fueling up.
So next time you head out in the heat, ask yourself: Is this fuel a friend or a foe today?✨ What fuels you in the spring might fight back in July. Adapt accordingly.