Polarized Training: Super Easy or Super Hard
Skip the medium-effort junk zone; train either very easy or all-out
- Difficulty
- Moderate
- Time to result
- ~weeks to results
- Steps
- 5
- Confidence
- 79%
Greenfield warns that training for aesthetics or performance is not the same as training for health; two decades of Ironman left many athletes he tested with thyroid and endocrine dysregulation, low bone density, and inflammation. His fix is polarization: since the human body is innately good at endurance, you only need to touch true endurance once a week, and the only chronic repetitive cardio worth doing is walking. Most people who think they are in an easy aerobic 'zone 2' are actually grinding in medium-intensity 'no man's land,' hard enough to drain the body but not enough to build fitness. Instead, make the majority of training either super easy, like a walk in the sun or light yoga, or super hard, like a single-set-to-failure strength circuit or short 30-seconds-on, 30-seconds-off intervals, then stop.
Origin
Greenfield distilled the model from 20 years of Ironman and sprint racing plus his book Beyond Training, after seeing chronic mid-level cardio wreck the biomarkers of thousands of endurance athletes.
Core principles
- 01Fitness and performance are not synonymous with health
- 02Humans are innately built for endurance, so little chronic cardio is needed
- 03Medium-intensity 'no man's land' drains the body without fitness payoff
- 04Most of the day should be low-level movement, with brief all-out efforts
How to run it
- 1
Cap true endurance at once a week
Reserve one weekly session for sucking air a little more, a hilly hike, a ride to a neighboring town, or a long swim.
Pro tip The body outlasts most animals given food and water, so it needs very little dedicated endurance training.
- 2
Make walking your only chronic cardio
Keep repetitive low-level cardio limited to walking, such as an easy walk in the sun with the dog or a treadmill stroll while talking.
Pro tip If you can hold a full conversation without sucking air, you are genuinely in the easy zone.
Watch out Most joggers who think they are aerobic are actually well above zone 2.
- 3
Do all-out strength in one set to failure
Run a single set to failure per movement, deadlift, chest press, pulldown, squat, overhead press, row, with high time under tension.
Pro tip Greenfield's full strength session is about 20 minutes, roughly three minutes per movement, going balls-out with no sitting around.
- 4
Replace medium cardio with short hard intervals
For conditioning, do brief hard intervals such as 30 seconds easy, 30 seconds hard for 20 minutes, then stop.
Pro tip Adding an oxygen-restriction device raises the difficulty without adding time.
Watch out Avoid the 'no man's land' of long medium-effort cardio that produces arterial stiffness and inflammation.
- 5
Fill the rest of the day with easy movement
Outside the brief hard efforts, keep everything hyper-easy and low-level throughout the day rather than adding more medium training.
In the wild
Greenfield describes a single-set-to-failure circuit, one all-out set each of deadlift, chest press, pulldown, squat, overhead press, and row, about three minutes per set, done in 20 minutes with no rest sitting around. His cardio the day before was a 30-seconds-easy, 30-seconds-hard interval workout on an air bike with an oxygen-restriction device for 20 minutes, then done.
→ A weekly plan that is either very easy or very hard, avoiding draining medium-intensity training.
Common mistakes
Living in no man's land
Training hard enough to drain but not hard enough to build fitness produces stiffness and inflammation with no payoff.
Confusing fitness with health
Assuming an Ironman or heavy endurance schedule is automatically healthy ignores the endocrine and inflammatory damage it can cause.
Is it for you?
Best for
Recreational exercisers and endurance athletes stuck in chronic mid-level training.
Not ideal for
Competitive endurance racers who have consciously accepted trading health for performance.
From the transcript
“the majority of your training should be super easy or super hard right so when you get in you just drain yourself”
“a lot of people think they're zone two and they're way above it... hard enough to where you're draining your body without much points like…”
From the episode
How To Biohack Your Sex Life - Ben Greenfield - #527
Ben Greenfield