Zone 2 Training

I’m a calisthenics person who runs, not a runner who does pull-ups. But training for Hyrox races and a half marathon taught me that a decent aerobic base makes the skill work better too: I recover faster between sets, between sessions and between hard weeks. The cheapest way to build that base turned out to be running slower than felt reasonable.

What zone 2 is

Heart-rate zones split effort into bands. Zone 2 is the top of “easy”: you can hold a conversation in full sentences, breathing is deeper than at rest but controlled, and you could keep going for a long time. For most people it’s around 60–70% of maximum heart rate, though the better definition is physiological: the highest intensity at which you’re still mostly burning fat and clearing lactate as fast as you produce it.

Why it’s worth caring about:

• It trains the mitochondria in slow-twitch muscle fibres, the machinery for using fat and clearing lactate (San-Millán and Brooks, 2018).
• It improves the heart’s stroke volume: more blood per beat, so the same pace costs fewer beats.
• It’s cheap to recover from. You can do a lot of it without eating into strength or skill work. That matters when calisthenics is the priority.

Endurance athletes tend to spend around 80% of their training at low intensity and only a small fraction hard (Seiler, 2010). Most amateurs, me included at first, do the opposite: every run drifts into a medium-hard grey zone that’s too hard to recover from and too easy to build much speed.

How I run it

• Start slower than you think. If you go out at your normal pace you’ll be in zone 3 within ten minutes and stay there. Drifting up shifts you towards burning carbohydrate, and slowing back down doesn’t switch you back instantly.
• Walk if you need to. Run/walk intervals, couch-to-5k style, keep the heart rate in range and keep it fun. There’s no shame in walking up a hill.
• Use the whole run. Zone 2 for the entire session, not as a warm-up to something harder.
• Keep the hard stuff separate. One interval session a week at race pace, with proper standing rest between reps. Jogging the recoveries just adds fatigue without adding quality.

Measuring progress

The indicator is simple: pace at a fixed zone 2 heart rate goes up. Same effort, faster running. It’s slow and it’s boring and it works. A 10k PB eventually happened inside a normal training week, without a dedicated block, which I’m fairly sure was the base doing its job.

Fitting it around calisthenics

• Two runs a week was enough for my goals: one long easy run and one interval session.
• Easy runs go on days with no heavy pressing, so they don’t steal recovery from skill work.
• If a strength session and an interval run share a day, I either do strength first or leave about six hours between them.
• A bit of lower-leg and hip work keeps the running pain-free: tibialis raises, calf raises, couch stretches. They’re in my single-leg progressions.

The engineering version

Zone 2 is the boring reliability work: the steady background capacity that makes everything else recover faster. Teams that spend every sprint in the grey zone, always slightly too busy, never truly resting and never really sprinting, get the same result as runners who do every run at medium pace. Plenty of fatigue, not much adaptation. Keep the easy work easy so the hard work can be hard. It’s the same logic as Calisthenics Programming: Skill vs Hypertrophy Phases.

Sources

• San-Millán, I. & Brooks, G. A. (2018). Assessment of metabolic flexibility by means of measuring blood lactate, fat, and carbohydrate oxidation responses to exercise in professional endurance athletes and less-fit individuals. Sports Medicine, 48(2), 467–479.
• Seiler, S. (2010). What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance, 5(3), 276–291.