PrometheusGeneral

Zone 2 training and Caffeine + L-Theanine

Each entry’s own grades, side by side. A grade says how strong the evidence is for one outcome — it does not rank one entry over the other.

Compound or practice

Zone 2 training

The unglamorous aerobic base that moves resting HR, mitochondria, and long-term health risk more than anything else per hour.

Grade A4 graded outcomesrevised Jun 22, 2026

A hand-written entry in Prometheus's bundled library. Its grades are the entry's own reading of the evidence, not a peer-reviewed review.

Compound or practice

Caffeine + L-Theanine

The best-documented nootropic stack there is: coffee's focus without the jitter tax.

Grade B4 graded outcomesrevised Jun 12, 2026

A hand-written entry in Prometheus's bundled library. Its grades are the entry's own reading of the evidence, not a peer-reviewed review.

Swap the two

Graded in both

Outcomes are matched by name. Two entries can describe the same outcome in different words, so one listed further down may still be graded in the other.

No outcome has the same name in both entries. They may still overlap under different wording — read the two lists below.

Graded only in Zone 2 training

  • Resting heart rate Moderate effectEvidence grade A
  • VO₂max (untrained→trained) Large effectEvidence grade A
  • Fat oxidation capacity Moderate effectEvidence grade A
  • All-cause mortality (cohort) Large effectEvidence grade B

Graded only in Caffeine + L-Theanine

  • Sustained attention Moderate effectEvidence grade B
  • Reaction time Small effectEvidence grade A
  • Jitter / anxiety reduction vs caffeine alone Moderate effectEvidence grade B
  • Sleep harm from late dosing Large effectEvidence grade A

Conditions

  • HypertensionZone 2 training: ImprovesEvidence grade ACaffeine + L-Theanine: May worsenEvidence grade C

Only in Zone 2 training

Only in Caffeine + L-Theanine

What each entry says about the other

  • Zone 2 training’s entry · Goes with: 3–6 mg/kg caffeine pre-session is the best-evidenced ergogenic there is
  • Caffeine + L-Theanine’s entry · Goes with: Pre-session caffeine raises sustainable output at the same effort

Both columns are read from the entries as they stand in this library. A comparison is not advice to take either one, and it is no substitute for a clinician who knows the person.