Zone 2 cardio this, improve your VO2 max that. Runners everywhere have started obsessing over slow miles. The rise of the 80/20 rule has bred countless coaches and trainers who push the mantra of “you have to run slow to go fast,” encouraging runners to keep 80 percent of their weekly mileage in zone 2 while reserving the remaining 20 percent for moderate to higher intensities. But despite its popularity, one expert wishes more recreational runners would ignore this rule.
“Most runners should not be following the 80/20 rule because it’s based on research studies and analyses of elite runners who are logging a lot more mileage than your recreational runners,” says Vikash Sharma, P.T., D.P.T., O.C.S., C.O.M.T., of Perfect Stride Physical Therapy and a certified running coach. “‘Rules’ in general are flawed, because you can’t apply one rule to a large, diverse group of people with different goals and abilities.”
No one is denying that zone 2 training makes a strong case. Elite runners, for example, often thrive following the 80/20 rule due to their high overall weekly volume. Let’s say they’re logging 100 miles a week. Well, 20 percent of that still equals 20 miles of moderate- to high-intensity work, which is more than enough stimulus to drive results. The remaining 80 miles work well at lower intensities, supporting recovery from such intense volume.
Related: Want to Maximize Your VO2 Max? These Home Exercise Bikes Will Take Your Cardio to the Next Level
“With recreational runners, on the other hand, their 20 percent may not be substantial enough stimulus to drive the optimal adaptations for their racing goals,” Sharma adds. “If they are running 25 miles a week, they will only have five miles of moderate- to high-intensity running.”
This applies to more than just runners. It holds true for any training program where the goal is to apply enough stimulus to drive meaningful adaptation. Factors like mileage, experience level, race distance, and performance goals matter far more than blindly following preset percentages.
“All that being said, an 80/20 split might be too aggressive for new runners, especially if they have not built up a base. They might benefit from a lower volume of moderate to high intensity running initially,” Sharma explains.
Basically, the takeaway here is that no single rule fits every situation. Adapt your running plan based on your goals and current fitness levels. Then, continue to adjust as necessary.
Related: A Pro Marathon Runner Shares the Habits That Make Long Runs Feel Easier
This story was originally published by Men’s Journal on Feb 11, 2026, where it first appeared in the Health & Fitness section. Add Men’s Journal as a Preferred Source by clicking here.