Why Endurance Athletes Should Care About Their Mitochondria

After momentarily putting her career on hold in her mid-thirties to have a child, runner and professional obstacle course racer Rose Wetzel felt anxious to get back on the course last year. But as a new mom and older athlete, she knew she had extra obstacles to overcome. “I had everything going for me except one thing: my aging cells,” she says.

What Wetzel needed was a power boost on a cellular level. She found it when Spartan Races partnered with MitoQ, the company behind a supplement that sends a heightened quantity of antioxidant support straight into your mitochondria. “I started taking MitoQ consistently over a year ago, and it’s really helped me build a solid foundation to tackle not only my workouts, but anything life as an athlete, personal trainer, and mom throws my way,” she says.

For as much as athletes think about their heart, lungs, and muscles when it comes to strength, power, and endurance, they often overlook that much smaller player in the performance equation: their mitochondria.

“Mitochondria are tiny organelles inside your cells,” says David Hood, Ph.D., a professor and research chair in cell physiology at York University in Toronto, Canada. More specifically, they’re responsible for the majority of the chemical energy needed to power the cell’s biochemical reactions, according to the National Institutes of Health.

These “cellular powerhouses” are responsible for cell function, signaling and metabolism, regulating physical processes like hormone levels, and crucially, for giving our cells, organs, and tissues the energy they need to function. They do the latter by converting potential energy from food to adenosine triphosphate (ATP), the molecule that’s responsible for storing and releasing energy in the body. In the production of ATP, the mitochondria make damaging reactive oxygen species (ROS). As part of the energy production process, the mitochondria also make CoQ10, an antioxidant that helps to control ROS and support the mitochondria. Without this vital molecule, the cells can become damaged and the level of ATP that the mitochondria produce can drop. And ATP is what drives muscle contraction—a pretty important element of activity.

The connection between your mitochondria and endurance exercise is twofold: First, endurance exercise actually stimulates a process called mitochondrial biogenesis, according to research published in the American Journal of Physiology-Endocrinology and Metabolism. When you challenge your body with endurance exercise, you secrete a compound that works inside the cell to stimulate the mitochondria to proliferate.

As your mitochondrial quantity increases, so does the quality of those mitochondria, according to research published in the Journal of Applied Physiology. The more—and healthier—mitochondria you have, “the more ATP and energy you’ll be able to produce aerobically,” says Hood. “When you rely more on aerobic energy production, you tend to produce less lactic acid, which allows your muscle contractions to be more efficient and leads to less fatigue—which leads to more endurance.”

Another endurance benefit: As you make more mitochondria, you also make more enzymes that break down fat, says Hood. A well-trained person uses more fat for their energy and less carbohydrates. “It takes a much longer time to deplete fat than your limited carbohydrate reserves, which means you can run or cycle or swim for much longer periods of time,” he explains. When they’re functioning well, healthy mitochondria can help you recover from intense workout loads faster in terms of regenerating energy supplies.

However as a natural part of the aging process, the important support offered by CoQ10 in the mitochondria can decline, something that high intensity exercise can also induce by proliferating ROS. “A byproduct of mitochondrial respiration is the formation of reactive oxygen species,” says Hood. These molecules, called reactive oxygen species (ROS) are highly reactive or damaging to your cells.

Like everything else in our bodies, our mitochondria can become less efficient as we age. With increasing age, levels of CoQ10 in the mitochondria can decline by about 10 percent with each passing decade. When your mitochondria don’t function properly, it means they aren’t producing enough energy for your body to function properly. You’ll likely experience fatigue and lethargy, workouts can feel way tougher than they should, and recovery can take longer.

“Some people think that the more ROS you generate, the more likely your muscles are to fatigue,” Hood explains. “But the more mitochondria there are, the faster you’re going to recover in terms of regenerating energy supplies for the next exercise bout.” For this to occur however, you want to ensure the mitochondria are functioning well and healthy, so they’re best able to deal with the ROS.

Fortunately, just by engaging in endurance exercise, you’re helping your body’s mitochondria. Getting a good night’s sleep can be a good place to start, too. When you don’t get enough shuteye, it causes mitochondrial stress that could impair health, a study in the journal Sleep found. “Sleep is very much understudied in terms of what the benefits for mitochondrial content and function are,” says Hood, but it makes sense that a lack of sleep could cause low energy levels to sink further.

You can also give your mitochondria a boost by eating a diet full of antioxidant-rich fruits and vegetables. A diet that’s high in fat or not heart-healthy forces your mitochondria to work harder, which causes more oxidative stress (i.e., ROS).

However even if you’re exercising, eating well and sleeping a good amount, the natural age-related decline of CoQ10 levels within mitochondria can still occur. This could explain why athletes like Wetzel are experiencing a difference from taking MitoQ.

To best support mitochondrial health, antioxidants need to be able to get inside mitochondria, to where the ROS are produced. However mitochondria have a tough outer membrane that lets very little pass through. MitoQ claims it has isolated the active component of CoQ10 and given it a positive charge that enables it to be sucked into the negatively-charged mitochondria. Research has found that this novel antioxidant is able to be absorbed by the mitochondria hundreds of times better than regular CoQ10 or its active form, ubiquinol, which are only effective at getting into the bloodstream.

For the past 20 years, studies on MitoQ have focused on benefits to ongoing health, but it is now undergoing clinical trials to research performance benefits. Anecdotal evidence has shown that, when paired with smart training, MitoQ helps the body to better-absorb intense training periods and recover more quickly, and a clinical trial released in 2020 by Ulster University, Sport and Exercise Sciences Research Institute, found that MitoQ attenuates the damage that high-intensity exercise causes to mitochondrial DNA (mtDNA) in skeletal muscle.

Wetzel, who regularly podium places and just finished third in the 2021 Spartan US National Series, says she feels stronger and has been logging more miles than ever before over the past year. “Taking MitoQ allows me to stand on the starting line of a race next to people whom I am nearly old enough to be the mother of and feel confident that my body can hit its maximum capability just as well as theirs can,” she says. “Plus, I now have years of race experience to my advantage.”