Oxidative Stress, Antioxidants, and Sports
As we breathe in oxygen, our bodies consume it and use it to power bodily functions. An influx of new oxygen from exercise creates “oxidative stress.” Oxidative stress is a condition caused by a surplus of oxidants relative to antioxidants, resulting from increased oxygen consumption by the body.
Usually, the human body has a natural balance of oxidants/antioxidants. It uses antioxidants from our diet to counteract the leftover oxidants that float as free radicals in the body.
CrossFit, distance running, or other intense activities increase oxygen consumption. Specifically, increased oxygen consumption during exercise increases the ratio of oxidants to antioxidants.
As a result, Reactive Oxygen Species (ROS) are produced from available oxidants and are known to “cause damage to cell structures” such as carbohydrates and proteins and “alter their functions [1].” A net effect of this is that a link between increased oxidative stress and various pathological conditions has been observed in research. In addition, an increase in oxidants can be directly linked to factors such as increased intake of air pollutants and cigarette smoke.
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$56.98 Add to cartDoes the Type of Exercise Matter? Oxidative Stress in Sports
During high-energy exercise, a person’s oxygen consumption rate can increase up to 20 times. This response by the body is not unique to any particular form of physical activity. The amount of oxygen consumed directly relates to the intensity and duration of the exercise [2].
CrossFit
A study compared athletes completing the CrossFit workout “Cindy” (20 minutes of push-ups, pull-ups, and air squats) with a 20-minute treadmill run at 90 percent of max heart rate. This type of run was chosen to simulate the cardiovascular demand of the CrossFit workout “Cindy.”
The results showed consistency in the production of oxidative stress across the two exercise styles. Furthermore, the levels of oxidative stress experienced by the two groups of athletes were “statistically identical.”
The study concludes, “when closely matched for exercise time and intensity,” a CrossFit workout will likely produce the same oxidative stress as distance running [3].
Marathons and Ultramarathons
A study was performed on endurance runners competing in the famous Marathon Des Sables ultramarathon. Specifically, scientists sought to identify the best vitamins for athletes to reduce markers of inflammation during competition.
To measure this, scientists conducted a double-blind, placebo-controlled study on the runners, tracking levels of oxidative stress at multiple points: 21 days before, on the third day of the race, and at the end of the race.
One key marker scientists measured was plasma lipid peroxidation (PLP). PLP is a process in which free radicals “steal” electrons from the lipids in cell membranes, resulting in cell damage. Overall, the study found that all groups showed increased levels of oxidative stress, as measured by the biomarkers tested during the event.
However, the results also indicated that the group that received “multivitamin-mineral supplementation” had better outcomes than the placebo group†. Their daily supplementation with vitamins A, C and E prevented the expected spike in PLP from the ultramarathon [4]†.
Olympic Sports
Another study looked at 40 athletes competing in three different sports. All athletes were competing at international levels in basketball, wrestling and soccer. As before, they found that “types of sport had no impact on the levels of oxidative status markers.”
Moreover, they define “elite sports engagement” of any kind as a “potent stimulus of oxidative stress.” Finally, the study concluded with advice that “consumption of antioxidants is recommended as part of a training regimen [5]†.”
Decidedly, multiple studies show that, regardless of sport, oxidative stress is dependent on increased oxygen consumption. A dramatic increase in oxidants from exercise unbalances the body and, as a result, increases the prevalence of inflammation.
Following this, Dr. Kenneth Cooper, also a former marathon runner, observed that some long-distance runners experienced unexpected health challenges later in life, prompting further discussion around exercise intensity, recovery, and overall balance.
Oxidative Stress and Exercise in Age Groups
Oxidative stress is not limited to specific age groups either. For example, a study of more than 1,100 women ages 43-70 examined changes in the body at different levels of exercise. In detail, researchers wanted to understand the effect of exercise on Superoxide Dismutase (SOD) activity in the body.
SOD activity measures the body’s ability to neutralize free radicals and reduce harmful ROS activity.
Results showed SOD activity decreased as the women increased their level of exercise. The group that performed the most activity had the most significant drop in overall SOD activity relative to its non-vigorous counterpart [6]. In addition, another study examined oxidative stress induced by physical activity in independent, community-living elderly individuals. The study yielded crucial takeaways after measuring different levels of physical activity across the groups.
First, moderate to vigorous physical activity was a “protective factor against cellular damage.” Second, in the elderly participants, “physical activity decreased the total antioxidant status [7].” The results show the benefit of exercise even as we age. Yet the results again show that exercise increases the number of oxidants relative to antioxidants.
Regardless of age or exercise, markers of inflammation are more prevalent as oxygen consumption increases. Knowing this, how can coaches and athletes use this data to improve performance?
How Recovery Time for Athletes Is Affected by Oxidative Stress
A new and more common way to apply measuring markers of inflammation is to use them as a guide to recovery. One way to do this is to use them in conjunction, but not in place of standard performance tests. By doing this, coaches can better understand the physical response exercise causes in the body of elite athletes.
A 2016 article in the Journal of Strength & Conditioning Research advocates, “biomarkers are not a replacement for performance tests.” However, “when used in conjunction, they may offer a better indication of metabolic recovery status.” Measuring these levels can “improve a coach’s ability to assess the recovery period after an exercise session and to establish the intensity of subsequent training sessions. [8]”
Similarly, the journal Sports Medicine gives their “Practical Overview” to enhance recovery in team sport athletes. The journal looked at multiple studies on numerous combinations of food and nutritional supplements for improving recovery. They advise that “Overall, a nutrient-dense diet consumed throughout the day, in combination with a few selected supplements, can support the athletes’ recovery goals during the competitive season [9].”
Diet and Dietary Supplements Support Antioxidant Balance†
Ultimately, oxidative stress is a function of oxygen intake over time. Therefore, regardless of form, intense exercise unbalances the body’s oxidant/antioxidant balance.
Antioxidants from food and supplements can help support the body’s natural antioxidant systems involved in recovery†.
First and foremost, Dr. Cooper advocates eating a healthy, balanced diet as part of his 8 Steps to Get Cooperized™. Additionally, another step in his process is taking a daily nutritional supplement.
Key antioxidants in our diet include:
- Coffee and tea
- Beans
- Dark chocolate
- Fruits, especially blueberries, raspberries, strawberries, cranberries and pomegranate
- Nuts and seeds, especially walnuts and pecans, and sunflower seeds
- Vibrantly colored vegetables such as artichokes, bell peppers (all colors), beets, broccoli, red cabbage, carrots, kale, spinach and sweet potatoes
- Whole grains
The key antioxidants in vitamins, minerals and flavonoids include:
- Beta-carotene
- Coenzyme Q10 (CoQ10)
- Lutein
- Lycopene
- Quercetin
- Selenium
- Turmeric
- Vitamin C
- Vitamin E
- Zeaxanthin
- Zinc
Importantly, we advise consulting your physician before starting a new workout regimen to determine individual needs.
(Bonus: Learn about the vitamins and supplements professional trainers Shannon and Mary Edwards take and recommend for other active adults.)
About the Author: Jill Turner is the President of Cooper Complete® Nutritional Supplements, where she oversees product development and customer experience. She enjoys writing about vitamins, supplements, and preventive health to help consumers make informed, science-backed decisions.