I like coffee and I like to run, but running can sometimes lead to some sloshing around of coffee in my stomach and since hot brewed coffee is pretty acidic this can lead to some minor heartburn and indigestion. In fact, I have some problems with hot brewed coffee in this regard whether running or not. I can handle a cup or two of hot brewed coffee or espresso, but more than that can give me some acid reflux.
Looking for a solution awhile back and a better way to brew coffee to make iced coffee in the summer, I found some information about "cold" brewing, which in this case was actually just brewing coffee at room temperature. Here's how it works and why I do it.
Coffee brewed at high temperatures ends up being relatively high in acid, and you can taste this as bitterness. Different varieties of coffee beans have different acid content, so if you like a strong tasting dark coffee, you get more acid. For many people, that spells acid reflux.
Coffee brewed at room temperatures and even cooler, takes much longer to brew, but does not contain all of the acids and bitterness of hot brew. One cup of ground coffee can be brewed at room temperature in 3-4 cups of room temperature water in about 4-12 hours, and the filtered product is a strong extract that can be refrigerated for a few days without losing it's freshness, because it doesn't have all the acids in it that cause the volatiles to break down into nasty-tasting stuff. The extract can be used as a strong ingredient for coffee-based drinks or baking on it's own, or 1/4-1/2 a cup of extract can be brought up to a full cup of volume with water and then either heated or iced to make a delicious, smooth cup of coffee. Different varieties results in different strengths of extract, so your dilution rate and mileage may vary. I use a variety that makes a strong room-temperature brewed extract and then mix it 2:1 water and coffee for a medium-bodied cup of coffee.
The reason I use this coffee is threefold. For one, I like the smoother, less bitter flavor of the coffee. Secondly, the much lower acid content allows me to drink as much coffee as I want in a day without ever having any kind of acid reflux. In fact, I haven't had indigestion due to coffee for over a year of brewing like this now. Third, it makes awesome iced coffee drinks. Another reason to do it is that it doesn't require an appliance. You just need a jar or bottle you can brew with, and a funnel and some kind of filter medium. I use a paper towel and a large funnel from a local homebrew shop that has a screen insert in the bottom, which makes for a wider area for the liquid to filter through and speeds up the filtering process.
With room temperature brewed coffee, I can have two to three cups before I go out for a run or before a race and experience no ill effects, which reaping the benefits of my morning dose of caffeine.
If you like your coffee, but experience some heart burn, and particularly from running, experiment with room temperature brewing and you might find you like it. There are even some commercial cold-brewing containers/decanters with built-in filters on the market.