Wellness and longevity enthusiasts have found a new part of the body to optimize: your mitochondria.

Known as the powerhouse of the cell, mitochondria are responsible for producing the energy that powers nearly every cell in your body, giving them an outsized role in your long-term health.1

Now, a new study suggests that spending too much sedentary time may take a toll on your mitochondria—even if you’re otherwise healthy.2

What the Study Found

Prior research has linked a sedentary lifestyle to a lower number of mitochondria, but it was unclear if inactivity affects how well mitochondria function, said study author Iñigo San Millan, PhD, a professor of medicine at the University of Colorado Anschutz.

To test this, researchers recruited 19 healthy men, including nine with a sedentary lifestyle and 10 with an active lifestyle, defined as at least 150 minutes of aerobic exercise per week.

Researchers took small muscle samples from participants’ thighs and analyzed how efficiently the mitochondria inside those cells used sugar and fat to produce energy.

“What we saw is that, in the healthy sedentary individuals, there was already a significant dysregulation of the way cells work,” San Millan said.

In particular, the muscles of sedentary participants had 49% less MPC1, a protein that helps convert sugar into energy. Plus, the CPT1 enzyme, which is involved in processing fat, was only about half as active in sedentary participants.

This helps explain why inactive people aren’t able to use fuel as efficiently, said Satyajit T. Reddy, MD, a sports cardiologist at the Mayo Clinic. “They’re not able to use sugar or fat, which are the two main fuel sources for the body,” he explained.

Sedentary participants also had higher levels of lactate during exercise than the active men, suggesting that physical activity was more difficult for them and required a less efficient way of producing energy, Reddy explained.

“We’ve known that patients that are not as physically fit … will have higher lactates at a lower exercise level,” he said.

Together, these findings suggest that “even if you’re otherwise healthy with no diagnoses, just being sedentary can be a sign that your mitochondria are not working well,” Reddy said.

What This Means For You

Mitochondria are responsible for turning the nutrients you eat into energy your body can use. “Energy is required for everything your body does,” Reddy said. “It’s required to keep your heart beating. It’s required to think.”

Poor mitochondrial function has been linked to insulin resistance, type 2 diabetes, and other metabolic problems, and researchers believe changes in mitochondrial function may occur years before those conditions develop.3

That means even if someone appears healthy, weak mitochondrial function under the surface can set them up for metabolic issues later on. “It’s very important to keep your mitochondrial health optimized as much as you are able to,” Reddy said.

The new study emphasizes the importance of exercise for your mitochondrial function, but it has several limitations. It relied on a small group of men, so the findings may not apply to women. “Metabolic processes in women are slightly different,” Reddy noted.

Silvia Corvera, MD, a professor of molecular medicine at UMass Chan Medical School, also pointed out that the sedentary participants had a much higher average BMI compared to the active group. This makes it difficult to say if inactivity alone caused the sedentary group’s drop in mitochondrial function, or whether weight played a role.

That said, there’s no question that exercise supports your metabolic health. Aim for at least 150 minutes a week of moderate-intensity exercise, which can include activities like hiking, walking, or biking.4 “Those activities are good enough to maintain and keep good mitochondrial function,” San Millan said.