Polarized training divides endurance exercise into mostly low-intensity work and a smaller amount of high-intensity training, while minimizing efforts in between. In a first-person test, Tom’s Guide’s runner applied the 80/20 approach without a smartwatch or fitness app, using perceived exertion to judge pace.
The method is associated with a model popularized by Dr. Stephen Seiler. Its three zones are easy, conversational exercise; moderate work between aerobic and anaerobic thresholds; and demanding efforts such as intervals, sprints or hill work. Polarized training emphasizes the first and third zones and generally avoids the middle one.
For easy runs, the writer aimed for an effort of about 4 out of 10, describing it as a pace that could be sustained for hours while still allowing conversation. That accounted for roughly 80% of the training. The remaining 20% involved efforts rated 8 or 9 out of 10, or slightly longer stretches around 7 out of 10.
The approach replaces heart-rate monitoring with rate of perceived exertion, or RPE. The article notes that easy sessions should remain below the lactate threshold, while hard runs should feel genuinely challenging. One suggested interval workout begins with a brief warm-up, followed by 15 repetitions of 30 seconds at a hard effort and 20 seconds of recovery, repeated two or three times before cooling down.
The article cites research in the International Journal of Sports Physiology and Performance involving 30 endurance runners. Researchers found that polarized training could produce greater training effects than a moderately high-intensity, between-threshold program.
The writer says the main adjustment was getting used to running slower on easy days and pushing harder during intense sessions. The article also cautions that too much high-intensity work can contribute to fatigue, injury, stress and burnout, and emphasizes including easy days and active recovery.
Sources: Tom's Guide.