Summer running hits differently.
The sun’s blazing, humidity’s hanging in the air like soup, and suddenly your easy pace feels like threshold work. It’s not that you got less fit — it’s that your body is doing double duty.
When it’s hot, every system in your body is working overtime to cool you down. You’re not just running — you’re thermoregulating, sweating, breathing harder, and burning through glycogen at warp speed.
So if your summer runs feel like a grind, you’re not broken. You’re dehydrated, depleted, and under-fueled.
The fix isn’t running harder. It’s fueling smarter.
Hydration Isn’t Just Water — It’s Chemistry
Here’s the part most runners get wrong: hydration isn’t just about drinking enough water. It’s about keeping your electrolytes in balance.
When you sweat, you’re not just losing fluid — you’re losing sodium, potassium, magnesium, and chloride. Those minerals are what keep your muscles contracting, your nerves firing, and your heart rate stable.
Lose too much sodium, and your brain starts pulling fluid from your bloodstream into your gut (hello, sloshy stomach).
Lose too much magnesium or potassium, and your muscles revolt with cramps or fatigue.
Drinking more water won’t fix that — in fact, it can make it worse. You’ll dilute your sodium levels and set yourself up for hyponatremia, which is the fancy word for “you overhydrated and now your cells are freaking out.”
So what’s the move? Balance.
Hydrate throughout the day, not just right before a run. Use an electrolyte mix that contains sodium (400–800 mg per 16 oz is a solid range), plus potassium and magnesium.
And yes — you need this even if you’re not drenched in sweat. Hydration isn’t just about visible sweat loss; it’s about keeping your plasma volume stable so your cardiovascular system can do its job under heat stress.
Carbs Aren’t the Enemy — They’re the Hydration Hack
Here’s the part nobody talks about enough: carbs help you stay hydrated.
When you eat carbs, your body stores them as glycogen — and for every gram of glycogen, your muscles store about three grams of water.
So when you cut carbs, you’re not just losing glycogen — you’re draining your hydration reserves. That’s why runners who underfuel or go too low-carb often feel sluggish, dizzy, or “flat” in the summer.
Your body isn’t just low on energy — it’s literally low on water.
If you’ve ever finished a hot long run feeling like you aged a decade, that’s not just sweat. That’s depleted glycogen. Refueling afterward with a mix of carbs and electrolytes helps restore both — and your recovery will feel night-and-day different.
The Hormone Factor: Why Menopausal and Masters Athletes Feel It More
Here’s where things get real for my athletes in midlife or surgical menopause: hydration and carbohydrate metabolism change with hormonal shifts.
Estrogen helps with fluid retention, glucose metabolism, and thermoregulation. When levels drop, your body loses some of its natural ability to manage heat and maintain electrolyte balance.
That’s why hot flashes often feel worse in summer — and why dehydration hits harder.
Your solution isn’t “drink more water.” It’s to be strategic:
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Increase electrolytes (especially sodium and magnesium).
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Eat enough carbs to stabilize blood sugar and support glycogen storage.
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Avoid fasted training in the heat (it’s not a badge of honor — it’s a cortisol spike).
Fueling properly isn’t just about performance anymore — it’s about physiology.
How to Stay Ahead of the Heat
If you want to stay strong all summer, think of hydration and fueling as a system, not two separate checkboxes.
Start the day hydrated.
Add electrolytes before your run.
Fuel early and consistently — every 30–45 minutes on long runs.
Refuel after with a mix of carbs, protein, and electrolytes.
Don’t wait until you’re thirsty, tired, or dizzy to fix it — that’s your body’s emergency alarm, not a cue for “maybe I should sip something.”
If you really want to dial this in, my Fueling + Hydration Guide walks you through product breakdowns, sweat rate testing, and how to balance carbs and electrolytes for your individual needs — especially if you’re training through hormonal changes or heat adaptation phases.
Summer running doesn’t have to feel like survival mode.
It’s not about toughness — it’s about tolerance.
The more you understand your body’s chemistry, the better you can support it. And when hydration and fueling are dialed in, that sticky, sweaty mid-July run turns from “please end me” to “okay, I can do this.”
Your summer strength isn’t built in the miles. It’s built in the moments you choose to hydrate, fuel, and recover with intention.