Runners hear the terms aerobic and anaerobic thrown around, but understanding the difference between the two can change how you approach your workouts. Together, these energy systems form the backbone of smart training, and knowing when—and how—to tap into each one is the key to unlocking your best performance.
Ahead, you’ll discover how to arrive at a balance between aerobic and anaerobic training, which can help you achieve a new PR.
Aerobic and Anaerobic Running—Defined
The inner workings of your body during exercise are extremely complex, with countless processes firing every fraction of a second. In this case, we’re looking at the two key energy systems that your body uses during exercise.
“The word aerobic, quite literally, refers to exercise with oxygen,” Juli Benson, Olympian and run coach, previously told Runner’s World. Aerobic exercise is long, slow, easy running where your body can sustain a low effort because it has sufficient oxygen.
“Building an aerobic base allows you to burn fat more efficiently, increasing the body’s energy production over prolonged times,” Dylan Mutchler, DPT, CSCS, a doctor of physical therapy at Bespoke Physical Therapy in Del Mar, California, told Runner’s World.
Anaerobic exercise, on the other hand, translates to “without oxygen.” Your muscles have to break down sugar to power your movement (and create excess lactate in the process), Jeff Gaudette, San Diego-based owner and head coach of RunnersConnect, previously told Runner’s World.
The anaerobic system takes over during high-intensity exercise—think short, explosive motion—but the buildup of lactate during this process quickly limits how long you can sustain that effort.
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How to Incorporate Anaerobic Running Into Aerobic Distance Training
Aerobic training is the foundation of distance running, and it’s probably familiar to most runners. You go slow and steady for a long time, hovering around zone 2, which means about 60 to 70 percent of your max heart rate.
Before starting any sort of distance training plan, runners should spend at least a month building a base, Mutchler says, but those taking on a marathon for the first time may benefit from upward of two or three months of steady aerobic base-building before adding in any sort of speed training.
“Many runners begin to include anaerobic workouts too soon in their training when they would benefit more from focusing on their aerobic system,” Gaudette says. “The anaerobic system can develop quickly, whereas the aerobic system takes years to fully develop.”
The standard advice applies to both forms of training, though: Don’t do too much too soon, it could lead to overtraining and injury.
After you build your aerobic base and you’re ready for anaerobic work, coaches recommend starting with just one workout per week of training, buffered by recovery runs and off days. That’s because anaerobic speed sessions are demanding and require a lot from your body. But the payoff is more efficient mechanics and stronger fast-twitch muscle fibers, which can help you power up hills and hone your finishing kick.
Max-intensity sprints are a great anaerobic exercise, Janet Hamilton, exercise physiologist and running coach with Running Strong in Atlanta, told Runner’s World. Hamilton recommends two types of high-intensity sprints, starting with quick bursts of effort for those new to anaerobic work, and building up the work intervals as you progress:
The recovery between reps, Hamilton says, depends on the individual. The goal is for your heart rate to get down close to baseline level so you’re able to perform at max effort again for the next repeat. In general, the longer your sprint distance, the more rest time you’ll need before attempting that effort again.
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Matt Rudisill is an Associate Service Editor with the Hearst Enthusiast Group. A Nittany Lion through-and-through, Matt graduated from PSU in 2022 with a degree in journalism and worked in communications for the university's athletic department for the past three years as the main contact and photographer for its nationally-ranked cross country and track & field teams. Matt was also heavily involved in communications efforts for the Penn State football team’s 2024 College Football Playoff run as well as the Nittany Lion men’s basketball team’s 2023 NCAA Tournament appearance. In his role with Hearst’s Enthusiast Group, Matt contributes to both Runner’s World and Bicycling magazines, creating service content to benefit runners and cyclists of all ages. When he’s not out jogging, Matt can be found tweeting bad takes about the Phillies or watching movies.
