Can Chocolate Affect You When You're Running?

When you're trying to decide how to fuel up before and after a run, your go-to strategy may be to down a sports drink and chomp on an energy bar or piece of fruit. However, another option is chocolate. Some evidence suggests that consuming moderate amounts of chocolate could actually boost your performance during exercise and may also help improve your recovery afterward.

A chocolate bar and chocolate shavings. (Image: Leszek Kobusinski/iStock/Getty Images)

Chocolate Bars

In a study published in 1996 in "Biomedical and Environmental Sciences," 16 male college-age students who ate a chocolate bar before a moderate-intensity run had higher blood sugar levels 15 minutes into their run and all the way through 30 minutes after their run than when they had a placebo supplement. In fact, subjects' blood sugar levels dropped to below a normal range 30 minutes into their exercise when they had no chocolate. When subjects ate the chocolate bars, they also showed other indicators - such as a lower rate of perceived exertion and favorable blood lactate levels - which showed researchers that having a chocolate bar before exercise can help boost exercise stamina and improve recovery.

Chocolate Milk

Chocolate milk may help give you more power and help you run longer if you drink it before your workout, according to a study published in 2006 in the "International Journal of Sport Nutrition and Exercise Metabolism." In the study, cyclists who had chocolate milk prior to their workout reduced their standard bike ride time by about six minutes. Drinking chocolate milk after a workout may also be helpful. In the study, participants taking an indoor cycling class for one week improved their maximal oxygen uptake twice as much as others if they had chocolate milk after each workout. This measure indicates that indoor cyclers had greater endurance and showed better aerobic performance when they had chocolate milk after their cycling activity. Although this study didn't focus on runners, chocolate milk may offer you similar physical stamina benefits during long-distance runs. However, chugging down chocolate milk probably isn't ideal if you go only for the occasional short jog, according to "Fitness" magazine.

A Potential Function

In a study published in a 2011 issue of "Journal of Physiology," researchers split sedentary male lab mice into different groups to study the effects epicatechin, a chemical found in cocoa, on their physical performance. When researchers gave all groups a treadmill test, they found that mice given epicatechin and a light 15-day training regimen in advance outperformed control groups and an epicatechin group that did not exercise. Researchers also discovered that the group of mice that got epicatechin and no exercise outperformed a group that got exercise but no epicatechin. After researchers biopsied the mice's muscles, they found that the cells in the muscles of mice given epicatechin were making new structures that help produce cellular energy. The more of these structures a muscle has, the less susceptible it is to fatigue. Still, researchers would need to conduct more studies to determine whether this effect is identical in humans eating cacao-rich dark chocolate before a workout.

Considerations

Just because having some chocolate may help boost your running performance doesn't mean you should feel free to chomp or guzzle it down. Chocolate is packed with sugar, and many Americans have more than is recommended. The American Heart Association recommends that women stick to no more than 24 grams of sugar a day and men limit their intake to about 36 grams a day. As a point of reference, one 1.45-ounce bar of dark chocolate contains approximately 9.5 grams of sugar and one 8-ounce cup of chocolate milk made with syrup can cost you about 32 grams.