A Single Session of Moderate-Intensity Exercise Benefits Your Cells in a Big Way

It may stimulate your mitochondria, which is responsible for turning fuel into energy. Here’s why that’s important.

By Elizabeth Millard

Apr 6, 2021

Jason Frank

• One session of moderate aerobic exercise can charge up your cells, according to a recent study in Medicine & Science in Sports & Exercise.
• Exercise may stimulate small changes in mitochondria—which is responsible for turning fuels like fats and sugar into energy—and when stacked up over time, could increase efficiency in fuel metabolism.

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If you’re starting an exercise routine for the first time or getting back into it after a winter break (or, let’s face it, a pandemic year), here’s some good news to keep you motivated: Just one session of moderate aerobic exercise can charge up your cells, according to a recent study in Medicine & Science in Sports & Exercise.

Researchers recruited 15 women and men in their 20s and 30s, who reported being generally sedentary, and had them ride a stationary bike for an hour at a moderate intensity.

Muscle biopsies done before and then 15 minutes after showed a significant post-exercise difference in cell mitochondria—the part of the cell responsible for turning fuels like fats and sugar into energy (think of it as the calorie furnace for the body). After cycling, participants’ mitochondria burned about 12 to 13 percent more fat and 14 to 17 percent more sugar.

“Exercise stimulates many aspects of metabolism,” lead author Matt Robinson, Ph.D., assistant professor in the College of Public Health and Human Sciences at Oregon State University, told Runner’s World. “We wanted to investigate the short-term effects of exercise directly on skeletal muscle mitochondria, which are the main site of fuel metabolism.”

Although the effects were mild with just one session, he added, they were consistent. That means a single session of exercise may stimulate small changes in mitochondria, and when stacked up over time, could increase efficiency in fuel metabolism.

One limitation here is the small participant number and inclusion of younger people only. However, it’s very likely that the result would be similar across age ranges, added study co-author Sean Newsom, Ph.D., assistant professor in the College of Public Health and Human Sciences at Oregon State University.

“People of all ages can increase mitochondrial fuel metabolism with aerobic training,” he told Runner’s World. “Findings like these are very encouraging, particularly for aging populations that often have declines in mitochondria.”

In other words, younger people may appreciate the calorie-burning effects of improved mitochondria function, but those who are older may benefit even more. As we age, the accumulation of cell damage—prompted by everything from illness to slower cell turnover —can cause a decline in mitochondrial function, previous research has noted.

Does that mean one session of riding prompts your cells to perk up enough to slow the aging process? Maybe not, but as you increase those sessions, you could be giving your cell function a healthy boost.

Elizabeth Millard Elizabeth Millard is a freelance writer focusing on health, wellness, fitness, and food.