Trail Chef: The Caffeine Buzz

Does caffeine boost or bonk your trail endurance?
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Does caffeine boost or bonk your trail endurance?

The other day at the grocery store, I grabbed a couple of bottles of Vitamin Water and noticed some of the flavors now have caffeine. This recent (to me) development is just one example of the caffeine craze sweeping the food aisles, with more and more gels, bars, blocks, drinks, and even baked goods (google Buzz Donuts) caffeinating up. So is this bandwagon a good one for backpackers to jump on? That’s a hard question to answer, since the caffeine debate is filled with pros and cons, fact and fiction. Here, we’ll attempt to dispel some of the myths and answer some of the most commonly asked questions about caffeine and sports performance. 

1. Does caffeine dehydrate you? Probably not. Although it is a diuretic (meaning it causes peeing), this effect is short-lasting, so you still get more water from a caffeinated beverage than you lose. This was confirmed in a 2007 study published in the International Journal of Sport Nutrition and Exercise Metabolism, which found that caffeinated sports drinks hydrated cyclists (who were asked to bike for more than two hours in hot, humid weather) just as well as non-caffeinated sports drinks.

2. Will caffeine make you hike faster? Yes and no. For long, endurance activities—think an all-day hike—research suggests that, indeed, caffeine does increase your stamina. Presumably, it does this two ways: first, by triggering your cells to burn more fat for energy, thus preserving glycogen stores (when cells run out of glycogen, you bonk, aka “hit the wall”). Secondly, caffeine also beguiles the brain into thinking it’s not working as hard as it really is. In tech-speak, it lowers your perceived exertion. Caffeine does not, however, appear to boost performance for short, intense bursts of activity—like a final sprint to the summit.

3. When’s the best time to take caffeine for the greatest effect? This question still needs more research to answer, but some studies suggest that taking caffeine three to four hours before exercise—for example, drinking a cup of coffee as you drive a couple hours to the trailhead—has the greatest impact, because it best preserves your glycogen stores.

Some caveats: Despite the alluring idea of a Starbucks grande transforming you into Ed Viesturs, caffeine doesn’t help everyone. For one thing, it increases the production of stomach acid, so it can irritate your belly, especially if you have ulcers. Other people also find that it exacerbates GI cramps and runner’s trot (diarrhea) by triggering large-intestine contractions.

The takeaway message: Don’t try out caffeinated drinks and foods for the first time the day of an important hike—like a life-list peak you want to tag. Test them out on hikes beforehand, to see if they jive (jiva?) with your body. Also, beware of caffeine withdrawal: Every weekend, I binge on chocolate-covered espresso beans on the trail, and then on Monday, quit cold-turkey. The result: headaches, fatigue, crabbiness, and, to borrow an Office Space line, a severe “case of the Mondays.”

—Trail Chef, Kristin Bjornsen