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Corpus is the dump and the study notes. Published targets use our synthesis — see Home and Method. The board uses what we publish.

Cardio — Zone 2

Subject: Siim Land · Window 2023-09-18 → 2026-09-18
Pass: 2026-09-18

Summary (primary sources)

Claim type What Siim says Source
Definition (HR) Zone 2 ≈ 60–70% max HR (also: Zone 1 50–60%, Z3 70–80%, Z4 80–90%, Z5 90–100%) YT J1gO-ZYxS-Q
Personal dose (site / earlier routine) 1 interval + 2–3 Zone 2 / week siimland.co
Personal dose (2026 plan) 2×/week Zone 2 + 1×/week HIT 4×4; more Zone 2 base for running goals YT OceysodInIo ~34:14
Session length (his Zone 2 experiment) 45–55 min, HR roughly 115–145 bpm (nose-breath / no burn heuristic) YT J1gO ~5:01
Expert/general cue he quotes “at least three hours a week of that zone 2” (opening of Zone 2 video — attributed as what experts say) YT J1gO ~0:09
VO2 result he reports 53 → 66 ml/kg/min after ~3 months Zone 2 emphasis YT J1gO; X 2024-06-05
2025 dip Less consistent cardio in 2025 (“maybe once a week HIT or Zone 2”) YT OceysodInIo ~31:23

YouTube — exact quotes + timestamps

I Did Zone 2 Cardio for 10 Months (J1gO-ZYxS-Q) — 2024-06-05

URL: https://www.youtube.com/watch?v=J1gO-ZYxS-Q · raw-transcripts/J1gO-ZYxS-Q.en.srt

Timestamp Quote
0:02–0:11 “Zone 2 cardio is one of the trendiest forms of exercise that many doctors and Longevity experts are raving about… you probably need to be doing at least three hours a week of that zone 2 which is building an aerobic base”
0:44–0:55 “Zone one which is 50 to 60% of your max heart rate zone 2 60 to 70% Zone 3 70 to 80% Zone 4 80 to 90% And zone 5 90 to 100%”
0:58–1:08 “Zone 2 is a lighter form of exercise where your body is burning the most amount of fat for fuel it sits just below the an[a]erobic threshold…”
1:51–1:59 “…the goal of Zone 2 training to increase your [anaerobic] threshold and lactate threshold… patients spend 80% of their cardio training time in zone [2]” (guest/expert clip in video)
~5:01–5:07 “Zone 2 card[io] [sessions] per week lasting for 45 to 55 minutes each my heart rate stayed between 115 to 145 beats per minute”
5:48–6:08 “…before I started doing Zone 2… 53 ml… per kilogram per minute… after having trained Zone 2 for 3 months… 66 … elite category of 18y[ear] olds”
6:30–6:36 “220 minus 18 is 202[?] and 60 to 70% of that is 121 to 141 this is the heart rate zone that I’m now tracking for doing Zone 2 cardio”
6:49 “during the first 3 months of my zone 2 training my V[O]2 Max went from 53 to 66 ml per kilogram per minute”

My 2026 Longevity Roadmap (OceysodInIo) — 2026-01-05

Timestamp Quote
31:23–31:43 “Cardio… 2025 was actually a time where I was doing much less cardio… Maybe doing it once a week, either hit cardio or zone two cardio.”
32:09–32:17 “Or I did a zone two cardio, mostly cycling… 60 minutes of low intensity.”
33:40–34:10 “Zone two cardio… I need to build a bigger cardio respiratory base… that requires a lot more hours doing a zone two cardio.”
34:12–34:21 “I’ll just do once a week the hit 4 by 4 protocol, but I’ll do twice a week zone two cardio. And the reason I do the zone two instead of adding an additional hit is because I already have several days of high intensity training.”
1:02:05–1:02:08 Weighted vest walking as “low zone one, zone two cardio” — see walking

30 Seconds… (F__fxx_E9p4) — 2026-03-26

Timestamp Quote
5:20–5:25 “Zone two cardio at 60 to 70% max heart rate about once or twice a week. The reason I incorporate more of the zone two is because I’m getting [enough] training stimulus on my nervous system from strength training.”

siimland.co

Page: https://www.siimland.co/my-longevity-routine

“You can increase your VO2 max with regular slow steady state cardio also called zone 2 training or with high-intensity interval training. The most optimal way is to obviously do both.”

“I do 1 interval workout per week and 2-3 zone 2 workouts per week because it’s associated with lower mortality risk in research. A 2023 systematic review found that the more moderate physical activity the lower your all-cause mortality risk (R). It even outperformed vigorous activity at high levels (-17% vs -35%). Thus, you don’t get progressively more benefits the more vigorous exercise you do - you hit a plateau after 200 minutes/week. However, you do keep getting benefits the more moderate exercise you do (800 min/week is better than 200 min/week).”

“The lowest mortality risk has been observed at a VO2 max of about 49-50 mL/kg/min (R). I have measured my VO2 max, and I got a score of 53, which puts me in the lowest risk category.”
(Note: later YT/X report 66 after Zone 2 block — chronological update.)

X @siimland (Zone 2)

Date URL Exact text
2023-11-20 https://x.com/siimland/status/1726589501458498000 “Zone 2 for 45-60 min 2-3x a week and 1x HIIT workout per week”
2024-06-24 https://x.com/siimland/status/1805258450043081129 “Current workout split: … Zone 2 cardio 2x week 60 min · HIIT cardio 1x week 30 min …”
2024-06-05 https://x.com/siimland/status/1798333225632465276 “I took my VO2 max from above average to the elite level in 4 months From 53 to 66 ml/kg/min … racked up a lot of hours of zone 2 cardio Made a video https://youtu.be/J1gO-ZYxS-Q”
2024-12-25 https://x.com/siimland/status/1871942683083653452 “Zone 2 cardio 1-2x/week and HIIT 1x/week”
2025-12-12 https://x.com/siimland/status/1999526839275102331 “Zone 2 cardio 1x/week · HIIT 1x/week” (2026 peak-health checklist — lighter Zone 2 count than personal 2× plan)
2026-07-28 https://x.com/siimland/status/2082152635960857039 “… zone 2 cardio 2–3x/week · HIIT 1x/week …” (visceral fat post)
2025-06-04 https://x.com/siimland/status/1930348400295260528 Level 2 adds “zone 2 cardio 60 min/week”
2026-07-09 https://x.com/siimland/status/2075235881900720284 “Exercise tierlist: … Zone 2 cardio: 6.5/10 …”

Studies Siim cites (Zone 2 / moderate activity)

→ Sources Siim cites — 2023 systematic review (exact title/DOI still TBD from his “(R)”)

Backlog — Zone 2