Using rucking for zone 2 cardio

Rucking at moderate pace with 15–20% body weight achieves zone 2 heart rate for many people who cannot reach it with unloaded walking.

Why it works

Zone 2 aerobic training — the intensity where you can still converse but are breathing noticeably — is metabolically important for mitochondrial biogenesis and fat oxidation but elusive for people who are fit enough that ordinary walking is below zone 2 and not yet able to sustain jogging. Adding load to the same walking pace raises heart rate into zone 2 territory while maintaining the low-impact mechanics of walking — delivering the training stimulus without the repetitive impact forces of running.

How to do it

1. Monitor heart rate during a flat-ground ruck. Target 60–75% of max HR.
2. Adjust load or pace until you hit that zone — you should be able to speak in full sentences but breathing is noticeably elevated.
3. Log sessions of 45–60 minutes at zone 2 heart rate as quality aerobic work.
4. Ruck 3–4 times per week to accumulate the ~180 minutes of zone 2 per week that the aerobic base literature supports.

Evidence

Load carriage studies confirm that adding load raises relative exercise intensity at a given speed. The zone 2 application is mechanistically straightforward; direct zone 2 rucking research is limited but the physiology is not in question. (mechanistic)

Zone 2 heart rate boundaries vary by individual; personalized HR monitoring is important — using a fixed formula without testing may misallocate the training zone.

Common mistake

Walking too fast with the load rather than slowing pace to maintain zone 2 heart rate — pace and load must be co-adjusted to hit the target intensity, not maximized independently.