Coenzyme Q10, Exercise and Oxidative Stress

The relationship between athletic performance and CoQ10 is still unclear. (Photo by foxypar4)

I've been taking 200 mg of CoQ10 (also known as ubiquinone) daily for more than two months now to see whether it has an effect on general health and exercise performance. While I haven't noticed much of a change, I've ran across some interesting information regarding coenzyme Q10 that I thought would be useful to share.

First off, there is a lot of anecdotal evidence on the benefits of using ubiquinone while doing strength training or aerobic exercise, but actual studies on the subject are rather inconclusive. In a 1997 study on Finnish cross-country skiers, 94% of the subjects reported improvements in performance and recovery time vs. only 33% with placebo. Measures of physical performance also improved significantly. The amount of coenzyme Q10 used was 90 mg per day.

In another study from the same year, male road cyclists and thriathletes were either given CoQ10 or a placebo. In the former group, plasma concentrations of CoQ10 increased significantly, but this had no significant effect on measures such as oxygen uptake, heart rate, and blood pressure. The amount used was 1 mg per kg of body weight, which is probably slightly less than in the other study.

In yet another study from 1997, 18 subjects were given either CoQ10 or a placebo. During running, there were no significant differences between the groups, but strangely, on a high intensity anaerobic cycling test, the placebo group actually did better. There is no mention of the amount used in the abstract.

In a study from 2005, six volunteers were first given a placebo, then 150 mg of CoQ10, then 150 mg of CoQ10 and 1,000 IU of vitamin E, and finally a placebo again. Plasma levels of CoQ10 increased slightly following supplementation, but muscle concentrations of CoQ10 or other measures showed no significant changes. There were no differences between the groups on a cycle test.

In a newer study from 2008, aerobically trained and untrained men and women were given either 100 mg CoQ10 or a placebo twice daily (yielding a total of 200 mg per day). CoQ10 supplementation resulted in higher muscle CoQ10 concentration, lower serum superoxide dismutase (SOD) oxidative stress, and higher serum malondialdehyde (MDA). In general, CoQ10 increased time to exhaustion on a treadmill.

One more study from 2008 concludes that oral administration of CoQ10 improved subjective fatique sensation and physical performance during workload trials. The subjects were given either a placebo, 100 mg of CoQ10 or 300 mg of CoQ10. Apparently there was no difference with the lower dosage compared to placebo, but 300 mg showed significant benefits.

So what does this all mean? It's difficult to draw conclusions, but two things that should be paid attention to when interpreting these studies are the dosage used and the time of ingestion. The Finnish cross-country skier study showed benefits with only 90 mg per day, but on the other hand, in the 2005 study with six volunteers, 150 mg per day had no effect. It's interesting to note that in the last study I mentioned, effects were visible only at the higher dose of 300 mg per day.

The time of ingestion is important because coenzyme Q10 also functions as an antioxidant, whereas exercise increases oxidative stress. The free radicals generated by exercise are neutralized by an antioxidant response from the body. Regular exercise thus enhances the antioxidant defense system and protects the body from free radical damage.

The relationship between exercise and antioxidant supplements is not entirely clear, but it has been suggested that ingesting antioxidants right before or after exercise negates some of the beneficial effects of exercise. Put simply, the theory is that when the body gets the antioxidants through supplementation, the body's own response to oxidative stress is negatively affected. This may be part of the reason why some studies show positive effects from CoQ10 and others don't.

Unfortunately, there is little information available on this subject, and spesific time intervals between exercise and antioxidant supplementation are hard to define. Nevertheless, it may be wise to not take any antioxidants a few hours before and after exercise. So far, I've been taking CoQ10 every morning, but from now on, I'll take it in the evening on days of exercise to see whether it makes a difference - and just to be sure I'm not missing out on the benefits.

For more information on coenzyme Q10, see these posts:

Coenzyme Q10 for Exercise & Better Health - Experiment Conclusion
The Role of Coenzyme Q10 in Oral Health
How to Choose Between Different Forms of Coenzyme Q10: Ubiquinone vs. Ubiquinol