What I Use on Long Runs to Avoid Chafing, GI Issues, and Blowups

Long runs are where most marathon training goes right, or quietly falls apart. It’s rarely fitness that ruins them. More often it’s chafing, stomach issues, dehydration, or small mistakes that compound over two or three hours.

Over time, I’ve learned that long runs aren’t the place to experiment. They’re the place to reduce friction, literally and figuratively.

I don’t overload my long runs with gear. I focus on a few things that consistently keep problems from showing up late, when it’s hardest to recover. Chafing prevention is one of the simplest and most important. If you’ve ever tried to “tough it out” through leg or seam chafing, you know how fast it can turn a good run into damage control. A small amount of anti-chafe before heading out has saved more long runs than any workout tweak ever has.

Fuel is the next piece. I aim for fuel that’s easy to chew, easy to digest, and predictable. On long runs, the goal isn’t excitement, it’s reliability. I want energy without spikes, crashes, or gut roulette halfway through. When fuel works, you barely notice it. When it doesn’t, the run is over long before your legs are.

Hydration matters just as much. I don’t wait until I feel depleted. I start early and stay steady, especially on warm days. A balanced hydration mix helps me avoid that foggy, flat feeling that creeps in when fluids and electrolytes fall behind. The difference shows up late in the run, not early.

What I avoid on long runs is anything new or untested. New flavors, new timing strategies, or “let’s see how this goes” ideas don’t belong when fatigue is already high. Long runs are rehearsals, not experiments.

I also pay attention to how much I use, not just what I use. Overfueling can be just as disruptive as underfueling. The goal is steady input that supports the effort, not forcing calories for the sake of numbers.

None of this is complicated, but it is intentional. The longer the run, the more small issues matter. Reducing friction, in your stomach, on your skin, and in your decision-making, is what lets fitness actually show up.

Long runs should challenge your endurance, not your tolerance for preventable problems. The right tools don’t make you faster on the day, they make sure the run actually does what it’s supposed to do.