Cardio
Zone 2
ProvisionalTargetEasy aerobic work at about 60–70% max HR, roughly 2×/week (2026 plan) for ~45–60 min/session, paired with 1×/week hard intervals — not instead of them.
Why it matters
Steady moderate work builds the aerobic base under HIT and lifting. Large long-term cohorts (and Siim’s 2023 review that points at them) show moderate-intensity volume keeps associating with lower mortality at high weekly minutes, while vigorous volume plateaus earlier — which is why he keeps a moderate lane even when he already lifts hard several days a week. His own reported VO2 jump after a Zone 2 block is his story, not Miles’s prescription.
Protocol
- Intensity: Zone 2 ≈ 60–70% HRmax — Siim-informed (YT definition).
- Frequency: 2×/week (2026 plan) or 2–3×/week (site / earlier X) — Siim-informed.
- Duration: 45–60 min/session (his experiment 45–55 min, HR ~115–145) — Siim-informed.
- Expert cue he opens with: at least ~3 hours/week Zone 2 — Siim-informed (attributed as what experts say).
- Pair with 1×/week HIT; don’t replace the hard day with more Zone 2 only — Siim-informed.
Evidence
O’Keefe JH, O’Keefe EL, Eckert R, Lavie CJ. Training Strategies to Optimize Cardiovascular Durability and Life Expectancy. Mo Med. 2023;120(2):155–162. PMID 37091937 · PMC PMC10121111. Full-text note: O’Keefe 2023.
Key finding (paper’s reading of Lee 2022): high doses of moderate PA reduce CVD/all-cause mortality more than high doses of vigorous PA; VPA mortality benefit maximizes ~150 min/week then plateaus; MPA keeps a dose-dependent inverse relationship.
Catch: Narrative systematic review (not a new pooled meta with extractable −17%/−35% cells); observational base; does not prescribe Zone 2 HR bands or 2×/week sessions.
Siim site (R): this PubMed ID is the exact href next to his 2023 moderate-vs-vigorous paragraph (scraped 2026-09-18). His “−17% vs −35%” and “200 / 800 min” framing are his numbers — not verified verbatim in O’Keefe full text → Partial match.
Lee DH et al. Long-term leisure-time physical activity intensity and all-cause and cause-specific mortality… Circulation. 2022;146(7):523–534. doi:10.1161/CIRCULATIONAHA.121.058162. Full-text note: Lee 2022.
Key finding: mutually adjusted MPA + VPA; near-max association ~150–300 min/week VPA or ~300–600 min/week MPA; higher bands don’t clearly add more; among people already ≥300 min/week MPA, extra VPA adds little.
Catch: Observational (NHS/HPFS self-report); not a Zone 2 training RCT.
Role: Landmark cohort under O’Keefe/Siim’s story — Partial as Siim cite (not the site href).
Garcia L et al. BJSM 2023 dose–response meta (doi:10.1136/bjsports-2022-105669) — prior-pass candidate; full-texted; not Siim’s (R); different MVPA mMET-h framing. Note kept under other/rejected-as-Siim-cite: Garcia 2023.
How Siim frames it
YT OceysodInIo 34:12–34:21 — once-weekly HIT 4×4 + twice weekly Zone 2 because he already has several high-intensity training days. → https://www.youtube.com/watch?v=OceysodInIo
Status
Provisional — protocol numbers from corpus are solid; full-text notes now on file for O’Keefe (his (R)) + Lee (underlying cohort). Gap: Siim’s exact −17% vs −35% and 200 / 800 min figures still unverified in those full texts; Zone 2 session dose remains Siim-informed, not study-prescribed. Not Locked until Product accepts that gap or we find a paper that states those exact numbers.
Full dump / backlog: corpus → Zone 2.