Mastering Summer Running: Fuel and Hydration Strategies in Heat

So, you know, fueling for some athletes is already a challenge, but the heat, as I said, and as we know, makes it a little bit more complicated.

And definitely if you're someone who's just kind of like getting by and winging it, you may feel the effects of the less than ideal, um, fueling plan or strategy during the hot weather.

So when it comes to what's happening, running in heat changes how you need to approach the hydration, fueling, and performance.

You know, maybe some gels or chews that you're used to taking, you can't tolerate.

You look at that gel and you're like, "There is absolutely no way." So when we're thinking about what's going on physiologically when we're running in the heat, uh, running in the heat is gonna put extra stress on your body.

It's gonna impact your sweat rate.

It will impact how your body is working and ability to tolerate the fuel.

So when we're thinking about it, your gut is going to do less when you're training in the heat, to put it very simply.

Um, blood flow during exercise is going to get redirected away from your digestive tract, right? That happens all the time.

That's why we like all of these sports fuels that are designed to be easily digested, and it takes that and put it- puts it prioritizes your working muscles.

So layer in hot weather, your body then has extra demands, extra stress to send more blood toward the skin to help you cool down through sweating and heat dissipation.

So circling back to the simple way to put it is your, your gut is gonna get less resources, right? Less support from your body.

Digestion is not a priority.

You know, as I tell some of my clients, especially when we're thinking about energy availability, this, this case with fueling in the heat is also, um, one of those situations where your body is always gonna prioritize the primary functions to keep you alive.

And while I think fueling is very important, and eating and digestion is important, when it comes down to the basics, your body is gonna work hard to keep the blood pumping, um, you know, keep you breathing, all of that, versus, "Okay, we need to digest and absorb this Clif Bar," or whatever food you might try to eat in the heat.

So that reduced blood flow and oxygen to your gut slows digestion.

That slowing of digestion can increase what's called intestinal permeability, which what does that mean for you? Runner stomach, right? Things like, uh, nausea, bloating, cramping.

That's how you will feel that manifest, and that is why, you know, maybe you're okay in cooler temperatures, fall, spring, winter, but when it comes to hot weather, this is very likely what's happening.

So of course, there are lots of other reasons [laughs] why you may experience GI issues during a run.

Um, but if you notice that it becomes more prevalent or it tends to always happen in the heat, this is very likely why.

And then there are ways, you know, that I work with clients as to like how we can troubleshoot, um, GI issues.

So that is a big piece of this.

Also, what is going on, your core temperature is elevated, and that is going to alter how your body uses fuel.

So- In these hot and humid conditions, your body, it has an accelerated glycogen burn rate.

For those who might be new around here or don't know, glycogen is your stored form of carbohydrate that's stored in the muscles and the liver.