Can Ingredients in Dark Chocolate Improve Exercise Capacity?

Dark Chocolate and exercise capacity

Who doesn’t enjoy a square or two of dark chocolate? It’s a tasty treat to eat, and it may do more than just tickle your taste buds. Studies show that dark chocolate is a heart-friendly treat but there’s an added perk. It may also improve exercise capacity, also referred to as aerobic capacity.

Exercise capacity is synonymous with exercise endurance. It’s a measure of how fit your cardiovascular and respiratory system is at delivering oxygen to tissues to sustain exercise. It’s also an indicator of how efficiently muscle cells can use this oxygen to make ATP to fuel exercise.

If you have greater exercise capacity, you can maintain aerobic exercise longer without becoming so fatigued you have to stop. You can improve exercise capacity through aerobic training by as much as 25%. However, research suggests that compounds in dark chocolate may give your exercise capacity an added boost too.

Can Ingredients in Dark Chocolate Boost Exercise Capacity?

The first evidence that dark chocolate might boost exercise capacity and endurance is in mice. The active ingredient in dark chocolate is catechins, particularly epicatechins.  Research has already linked the epicatechins in chocolate to reduced blood pressure levels and lower rates of heart disease. That’s why sources say that dark chocolate is heart-healthy.

Epicatechins have a favorable effect on blood pressure and heart disease risk because they increase levels of nitric oxide in the blood. This helps open up blood vessels to allow greater blood flow and oxygen delivery. They also help prevent platelet aggregation, which can be a precursor to heart disease and a heart attack.

For the mouse study, researchers at the University of California at San Diego put dark chocolate to the test. They gave one group of mice a 1-milligram dose of epicatechin in water twice a day while another group drank plain water. The mice took part in light exercise and then more intense treadmill exercise over 15 days.

The results? The mice that received the epicatechin-enriched water were able to run longer on the treadmill and developed less muscle fatigue. In fact, their resistance to muscle fatigue was 30% higher. The mice also had other performance-enhancing changes in their muscles. Mitochondria in the muscle cells that generate ATP for energy were more active, and there were more capillaries sending blood to their muscles. These factors would both help to reduce muscle fatigue and boost exercise endurance.

Do the Epicatechins in Dark Chocolate Increase Exercise Capacity in Humans?

It’s one thing for dark chocolate to improve endurance in mice, but what about humans? A 2016 study challenged 20 healthy, but sedentary, individuals with an average age of 50 to consume 20 grams of dark chocolate or a placebo for 3 months. Before, they measured their V02 max, as a marker for exercise capacity. After 3 months of consuming the dark chocolate or placebo, the researchers repeated the test. They also did a muscle biopsy and blood tests to look at the effects of dark chocolate on mitochondria and markers of oxidative stress and metabolic health.

The results? The group who consumed dark chocolate for 3 months showed a 17% increase in VO2 max, a marker of exercise capacity whereas the subjects who consumed the placebo experienced no change. The chocolate groups also experienced a rise in HDL and a drop in blood triglycerides, whereas the placebo group did not. How might the improvements in fitness capacity take place? Based on the results of the biopsy and blood tests, the researchers believe the epicatechins in dark chocolate enhance the efficiency of mitochondria, the tiny powerhouses that produce the ATP your muscle use during exercise. Could dark chocolate be the next best thing to exercise for improving fitness capacity and endurance?

How Much Chocolate Do You Need to Get the Benefits?

Based on studies, it doesn’t take a lot of dark chocolate to get the heart health benefits. About 10 grams of dark chocolate, less than a square of dark chocolate is enough to offer heart health benefits. In the human study on exercise endurance, they used a larger quantity of dark chocolate, 20 grams per day, which is double the recommended amount for heart health but still a reasonable quantity to consume. This would be the equivalent of a little less than a quarter of a standard dark chocolate bar.

Is some dark chocolate better than others?  Look for a dark chocolate bar that has a cacao content of at least 70%. Raw chocolate is ideal since the epicatechins in chocolate are sensitive to heat and heating it can alter their structure. Raw cocoa powder is another way to get chocolate catechins without the added fat and calories. Don’t add it to milk though. Milk may inactivate some of the flavanols and epicatechins.

Keep in mind that the quantity of epicatechins in dark chocolate can vary widely even with dark chocolate that has the same percentage of cacao. Do your research. There are sources, like Consumer Lab, that conduct independent testing of dark chocolate and cacao powder and nibs to see how much they contain.

Another Benefit of Dark Chocolate if You Work Out

Research shows the epicatechins and other catechin in dark chocolate reduce inflammation. Therefore, dark chocolate after a workout may help with muscle recovery. The catechins in dark chocolate may also give your brain a boost, and that may indirectly help your performance. Studies show that dark chocolate has mood-boosting benefits that may boost motivation too.

The Bottom Line?

Dark chocolate is one of the most indulgent foods that also has health benefits, and it may even help your exercise performance. Since chocolate is calorie dense, eat it in moderation and choose a bar with a low sugar content. If you choose a sugary bar, the negative effect of the sugar may outweigh some of the heart-health benefits.



  • J. Hypertens. 21, 2281-2286.
  • MedicalNewsToday.com. “What are the health benefits of dark chocolate?”
  • Food Funct. 2016 Sep 14; 7(9): 3686–3693.Published online 2016 Aug 5. doi: 10.1039/c6fo00611f.
  • Front Immunol. 2017; 8: 677.Published online 2017 Jun 9. doi: 10.3389/fimmu.2017.00677.
  • ScienceDaily.com. “Eating dark chocolate as a daily snack could help boost athletic performance”


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