RELATED: Antioxidants Have Mixed Effects on Performance

Why Is Exercise Good for Us if It Causes Stress?

Sandra Zakowski, a graduate professor of mine, once asked a question in class that has stuck with me for many years. We had been studying how stress reactions cause biological damage in the body. She asked how exercise, which is a stressor, can be so beneficial. I couldn’t answer the question then, and I have been struggling for years to get a handle on her query. But recent research may be pointing in the direction of an answer.

Antioxidants Have Negative Effects

Often touted for their beneficial effects, antioxidants are now being found to have some negative effects, especially on our bodies’ adaption to exercise. Here is a summary of three initial studies that found antioxidants limit the beneficial effects of exercise:

Scribbans and colleagues studied the effect of adding resveratrol to a Tabata-like program. Athletes trained for four weeks with three Tabata-style workouts per week. There were only sixteen people in this study and probably one of the reasons for the small sample size was that participants had to have muscle biopsies to see whether there was a change in muscle fiber. Participants in the placebo group showed more beneficial physiological changes in muscle biopsies than those not in the placebo group. Basically, their bodies began the process of adapting to the high intensity exercise protocol better.

“Often touted for their beneficial effects, antioxidants are now being found to have some negative effects, especially on our bodies’ adaption to exercise.”

Paulsen and colleagues investigated the effects of vitamins C and E on endurance training. They found no differences in VO2 max and other indicators of endurance. However, they did find differences in the markers of mitochondrial biogenesis (again with the muscle biopsies). This study had a larger sample size (n = 54) and the endurance training lasted eleven weeks.

RELATED: Antioxidants Improve Performance – But How?

Finally, a study by Gliemann and colleagues investigated cardiovascular effects in older physically inactive men. They found that exercise was effective in improving many cardiovascular indicators (e.g., LDL). However, resveratrol seemed to blunt the effects of exercise (again, it is better to be in the placebo group than in the antioxidant group).

Oxidative Molecules Vital For Disease Prevention

This mystery now leads us to Watson. Not Sherlock Holmes’ Watson, but James Watson, who won the Nobel Prize for the discovery of the structure of DNA. He recently presented a theory that diabetes, dementia, heart disease, and cancer are caused by a lack of reactive oxygen species. He cited similar studies showing the benefits of exercise on these disorders (e.g., Ristow and colleagues). He pointed out that oxidative molecules are vital to set in motion the body’s reactive mechanism that makes us more resilient.

RELATED: Resveratrol Shown to Boost Athletic Performance

Why Are Scientists Always So Confusing?

It is ironic that resveratrol was recently thought to have similar effects to exercise and might take the place of exercise. Rather than giving up and saying science can’t decide, we can look at the differing results and say they are pieces of the bigger puzzle. Reseveratrol used without exercise seems to have some protective benefits. When used before exercise, it seems to block the body’s natural reaction to dealing with stress.

As an analogy, we can liken the situation to using bands to assist with pull ups. In the short term, bands help you do more pull ups and make them look more efficient. In the long run, strength is not built (evenly), so the body does not improve. We need to have stressors in order to improve. Reactive oxygen species, thought of as one cause of aging and disease, might be necessary to signal healthy adaptations to exercise.

What Does This Mean for Me?

Most of this research has come out within the last few years and the results are starting to accumulate. One small study might not be meaningful, but we now have four or five studies pointing to the same outcome. Antioxidants, such as resveratrol and vitamins A and C, seem to interfere with the long-term benefits of exercise by interfering with the body’s adaptive mechanisms.

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I don’t think it is time to throw out all of your antioxidant supplements. However, it is probably best to get antioxidants from food. In these studies, the dosage is given in supplemental form and is higher than you would get through food.

References:

1. Gliemann, L., et al. 2013. “Resveratrol Blunts the Positive Effects of Exercise Training on Cardiovascular Health in Aged Men.” The Journal of Physiology 591 (Pt 20): 5047–59. doi:10.1113/jphysiol.2013.258061. 

2. Paulsen, G., et al. 2014. “Vitamin C and E Supplementation Hampers Cellular Adaptation to Endurance Training in Humans: A Double-Blind Randomized Controlled Trial.” The Journal of Physiology, February, jphysiol.2013.267419. doi:10.1113/jphysiol.2013.267419. 

3. Ristow, M., et al. 2009. “Antioxidants Prevent Health-Promoting Effects of Physical Exercise in Humans.” Proceedings of the National Academy of Sciences 106 (21): 8665–70. doi:10.1073/pnas.0903485106. 

4. Schmaus, BJ., et al. 2008. “Gender and Stress: Differential Psychophysiological Reactivity to Stress Reexposure in the Laboratory.” International Journal of Psychophysiology 69 (2): 101–6. 

 5. Scribbans, TD., et al. 2014. “Resveratrol Supplementation Does Not Augment Performance Adaptations or Fibre-Type–specific Responses to High-Intensity Interval Training in Humans.” Applied Physiology, Nutrition, and Metabolism 39 (11): 1305–13. doi:10.1139/apnm-2014-0070.

6. Watson, JD. 2014. “Type 2 Diabetes as a Redox Disease.” The Lancet 383 (9919): 841–43. doi:10.1016/S0140-6736(13)62365-X. 

Photos 1 courtesy of CrossFit Empirical.

Photo 2 courtesy of Shutterstock.

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Exercise creates what are called reactive oxygen species (ROS). They are a normal part of everyday life, but in high quantities ROS are also thought to be the major cause of aging and a possible contributor to cancer. The higher number of ROS that results from exercise increases the need for antioxidants, which eliminate ROS. Through acclimatizing to exercise, athletes can actually have greater antioxidant stores, and thus greater capacity to handle stressors like exercise in a healthy way.

This study was concerned with the acute effect of antioxidants on exercise. There were fifteen participants who each attended three exercise sessions. The first session familiarized the participants with the setup and the back squat, which was the exercise they all performed. The researchers also determined the three-rep-max of each participant on that first visit, in order to predict the loads for the protocol.

During the subsequent two visits, the participants performed the actual workout. They did six sets of ten reps, using seventy percent of their predicted one-rep-max. Prior to each of these workouts, they consumed either a Pycnogenol-based antioxidant supplement or a placebo made to look the same as the supplement. This was done in a random order for each participant to eliminate a possible training effect.

The results were clearly in favor of antioxidant use, but they were also a little confusing. The antioxidants allowed the participants to perform more work (i.e. more reps) at a greater velocity. As if that wasn’t enough to pique your interest, the benefit of more endurance and more speed extended across the entire workout. In other words, as you might expect, the placebo group experienced a waning in speed and power from the first set to the last, where the antioxidant group did not.

Based on these results, it’s obvious that antioxidants are good for size and strength even when used as a pre-workout supplement, since the participants took the supplement four hours before exercise. But the whys are still mysterious. Oxidative stress was measured by xanthine oxidase, which is a primary cause of damage from exercise. Xanthine oxidase was not lower in the antioxidant group, leaving the research team scratching their heads as to how the performance actually increased.

Not only that, but growth hormone release was also delayed and stunted by the antioxidant. This could be the result of differences in energy substrate utilization, and might indicate the possible cause of the performance boost.

In the end, we know antioxidants enhanced performance, but we don’t know why. In the future, more stress markers should be examined, and different sorts of antioxidants should be used. But for now it seems like a good idea to supplement with antioxidants for a variety of reasons, including improved performance.

References:

1. James Ackerman, et. al., “The effect of an acute antioxidant supplementation compared with placebo on performance and hormonal response during a high volume resistance training session,” Journal of the International Society of Sports Nutrition 2014, 11:10

Photo courtesy of Shutterstock.

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Resveratrol is sold as a nutritional supplement, and is derived primarily from Japanese knotweed. There have been reports resveratrol may aid in life extension, decreasing inflammation, lowering blood sugar, cancer prevention, and heart health.¹ However, extensive research has not been performed and there is not enough scientific basis to make some of these claims. The recent study on resveratrol and exercise performance was led by Jason Dyck, who is an Alberta Innovates – Health Solutions senior scholar and the director of the Cardiovascular Research Center at the University of Alberta.

Dyck and his team discovered that high doses of the natural compound resveratrol improved physical performance, heart function, and muscle strength in lab models. These findings were published in the peer-reviewed Journal of Physiology in late May.²

“We were excited when we saw that resveratrol showed results similar to what you would see from extensive endurance exercise training,” says Dyck, who works in the Faculty of Medicine and Dentistry as a researcher in the department of Pediatrics and the department of Pharmacology. “We immediately saw the potential for this and thought that we identified ‘improved exercise performance in a pill.’ “³

The findings in this study have resulted in Dyck and his team starting a new ten-week research study on the effects of resveratrol on diabetics with heart failure. The aim of this research is to see if resveratrol can improve heart function for these patients.⁴

“I think resveratrol could help patient populations who want to exercise but are physically incapable. Resveratrol could mimic exercise for them or improve the benefits of the modest amount of exercise that they can do,” says Dyck. “It is very satisfying to progress from basic research in a lab to testing in people, in a short period of time.”⁵

Although Dyck’s claim that resveratrol could be ‘improved exercise in a pill’ may be a little exaggerated, it is reassuring to see the potential benefits this naturally occurring compound could possess. Many athletes look for that extra edge that is both legal and safe, especially those whose career depends on performance. Fortunately, resveratrol looks to be a good addition to any athlete’s supplement regimen.⁶

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