Zone-2 Aerobic Base Session

A steady, conversational-pace session held in Zone 2 (~60-70% HRmax, RPE 3-4). This is the aerobic foundation that most weekly volume should sit on. Duration is a default; extend or shorten to fit your week.

How often: 2–5.6 sessions/week · trial frequency reported by the sources of the review summary this routine was written from (5 of 5 sources named by SR06.1 state one) · planning default: 3-5x/week · the review report’s bottom line: 2–3+ sessions/week (the report's bottom-line prescription)

When: any time · the sources state no time of day; the planner's slot is a default

The time slot is a planning choice: a swap can keep it.

The evidence applies to the practice, not to these particular steps — they are one way to carry it out.

1
Brisk Walk
5 min easy build to raise heart rate
Warm-up; ease into a conversational pace.
Slot: pre-activity preparation
Named by a Round-2 reviewMeets the finding's dose
9 options for this requirement
These are the practices the completed Round-2 reviews name for pre-activity preparation. The evidence rating on this routine belongs to the practice and its dose, not to any one of these. Choosing one changes what you read on this page only — it is not saved on any session in your week, and it never changes what the routine prescribes. To keep a choice, make it on the session itself in My Week.
Ballistic stretching
Compared in the review
10 papers put it in this slot · dose unit not stated
Evidence and how-to
Dynamic stretching
Compared in the review
40 papers put it in this slot · dose in sets × time
Cannot be used here: This step's dose is measured in duration and this option's in sets × time. Converting between them is not something the research says, so the swap is refused rather than converted.
Evidence and how-to
Dynamic warm-up
Compared in the review
6 papers put it in this slot · dose in duration
Evidence and how-to
Foam rolling
Compared in the review
7 papers put it in this slot · dose in duration
Evidence and how-to
Hold-relax
Compared in the review
1 paper put it in this slot (inferred by the extraction, not stated in the paper) · dose unit not stated
Evidence and how-to
PNF stretching
Compared in the review
4 papers put it in this slot · dose in duration
Evidence and how-to
Static stretching
Compared in the review
39 papers put it in this slot · dose in duration
Evidence and how-to
Strap-assisted
Compared in the review
1 paper put it in this slot · dose unit not stated
Evidence and how-to
Vibration-assisted
Compared in the review
1 paper put it in this slot · dose unit not stated
Evidence and how-to
2
Easy Run (Zone 2)
35 min continuous at RPE 3-4 (Zone 2)
Swap for bike or elliptical if you prefer low impact.
Slot: low-intensity / base volume
Named by a Round-2 review (by reading)Meets the finding's dose
3 options for this requirement
These are the practices the completed Round-2 reviews name for low-intensity / base volume. The evidence rating on this routine belongs to the practice and its dose, not to any one of these. Choosing one changes what you read on this page only — it is not saved on any session in your week, and it never changes what the routine prescribes. To keep a choice, make it on the session itself in My Week.
Cycling
Compared in the review
1 paper put it in this slot (inferred by the extraction, not stated in the paper) · dose in duration
Evidence and how-to
Swimming
Compared in the review
1 paper put it in this slot (inferred by the extraction, not stated in the paper) · dose in duration
Evidence and how-to
Walking
Compared in the review
1 paper put it in this slot (inferred by the extraction, not stated in the paper) · dose in duration
Evidence and how-to
3
Brisk Walk
5 min easy walk
Cool-down; let breathing settle.
Slot: post-activity
Named by a Round-2 reviewMeets the finding's dose
5 options for this requirement
These are the practices the completed Round-2 reviews name for post-activity. The evidence rating on this routine belongs to the practice and its dose, not to any one of these. Choosing one changes what you read on this page only — it is not saved on any session in your week, and it never changes what the routine prescribes. To keep a choice, make it on the session itself in My Week.
Ballistic stretching
Compared in the review
1 paper put it in this slot (inferred by the extraction, not stated in the paper) · dose unit not stated
Evidence and how-to
Dynamic stretching
Compared in the review
3 papers put it in this slot · dose in sets × time
Cannot be used here: This step's dose is measured in duration and this option's in sets × time. Converting between them is not something the research says, so the swap is refused rather than converted.
Evidence and how-to
Foam rolling
Compared in the review
1 paper put it in this slot · dose in duration
Evidence and how-to
PNF stretching
Compared in the review
3 papers put it in this slot · dose in duration
Evidence and how-to
Static stretching
Compared in the review
8 papers put it in this slot · dose in duration
Evidence and how-to

Safety, and where each line comes from

1 reported by the review's sources14 product safeguard (app-authored)5 source silent

Each line below says where it comes from. “Reported by the review’s sources” is the source’s own words about adverse events or contraindications. “Product safeguard” is written by this app, not by the research. “Source silent” means the studies behind this routine report nothing on that point, which is not the same as saying it carries no risk.

Who should modify or avoid this

Product safeguard (app-authored)Progress duration gradually to manage joint load
From this routine’s block record, written by this app.
Product safeguard (app-authored)All fitness levels, ideal for base-building
From this routine’s block record, written by this app.
Product safeguard (app-authored)Designed for generally healthy adults. A heart, lung or metabolic condition, or medication that affects heart rate, changes what is appropriate here.
Source silentThe sources behind this routine's finding report no contraindications or population restrictions.

Prerequisites

Product safeguard (app-authored)Written for beginner level. Equipment: none. Warm up before the working sets, and learn each movement at a light load or short range before adding effort.
Source silentThe sources behind this routine's finding report nothing on prerequisites or starting level.

Hazards and adverse events

Reported by the review's sourcesLikely adverse responders were observed in elderly participants and those with coronary artery disease or metabolic syndrome.
SR06.1 · canon row 1420, adverse events field · A Multi-Center Comparison of O2peak Trainability Between Interval Training and Moderate Intensity Continuous Training · studied: WHAT: High-volume HIIT involves more than 15 minutes of high-intensity efforts per session (e.g., 4 × 4-minute intervals at 90% peak heart rate). Low-volume HIIT/SIT involves less than 15 minutes of high-intensity efforts (e.g., 6 ×…
Product safeguard (app-authored)Brisk Walk: Choose even surfaces and supportive footwear; slow down if dizzy or short of breath.
From the exercise catalogue, written by this app.
Product safeguard (app-authored)Easy Run (Zone 2): If pace forces mouth-gulping breaths, slow down; build weekly mileage gradually.
From the exercise catalogue, written by this app.

Progression and regression

Product safeguard (app-authored)Brisk Walk: regress with Casual-pace walk; Shorter intervals with seated rest and progress with Incline walk; Nordic walking; Walk-jog intervals.
From the exercise catalogue, written by this app.
Product safeguard (app-authored)Easy Run (Zone 2): regress with Walk-jog intervals; Shorter distance and progress with Long slow distance run; Tempo run.
From the exercise catalogue, written by this app.
Source silentThe sources behind this routine's finding report nothing on how to progress or regress it.

Stop conditions

Product safeguard (app-authored)Stop if you feel chest pain or pressure, faintness, unusual breathlessness for the effort, palpitations, or pain in a joint that changes how you move.
Source silentThe sources behind this routine's finding report no stop conditions.

When to seek supervision or clearance

Product safeguard (app-authored)Chest pain, pressure, or unusual shortness of breath during exertion
From this routine’s block record, written by this app.
Product safeguard (app-authored)Fainting, dizziness, or palpitations with exercise
From this routine’s block record, written by this app.
Product safeguard (app-authored)Known or suspected cardiovascular, metabolic, or renal disease without medical clearance
From this routine’s block record, written by this app.
Product safeguard (app-authored)Get clearance from a clinician before starting if you have a heart or lung condition, uncontrolled blood pressure, diabetes on medication, or symptoms on exertion; start at a lower intensity than the routine states if you are new to exercise.
Product safeguard (app-authored)Signs of a medical emergency (chest pain or pressure, trouble breathing, fainting, sudden weakness or numbness) mean 911 or your local emergency services; thoughts of self-harm or suicide mean the 988 Suicide & Crisis Lifeline. This app does not diagnose, treat or give personalised medical advice.
Source silentThe sources behind this routine's finding report nothing on supervision or clearance.

How to do it

The review summary this routine was written from reports that cardiorespiratory fitness improves with aerobic training at every intensity band, with low-intensity endurance training on its own significantly improving aerobic fitness and showing a large effect on relative VO2max (effect size around 0.94). The same finding sets the boundary: head-to-head, higher-volume or higher-intensity work tends to produce somewhat larger peak gains, so conversational work is the dependable route to fitness rather than the fastest - and nothing here makes it a special fat-burning intensity for weight loss. The 45 minutes at this frequency is a practical implementation of that general result; the review summary this routine was written from does not validate this specific duration or weekly count.

Conversational is the test: RPE 3-4, roughly 60-70% HRmax, able to speak a full sentence. If you cannot, you are above Zone 2 and should slow down.
Hold the pace steady rather than letting it drift faster once you feel warmed up - drifting up is the usual way this stops being a Zone-2 session.
Bike, elliptical, or rower swap in directly for lower impact, and walking counts if jogging pushes you out of the zone.
Add duration before frequency, and add it gradually - joint load is what limits this session, not effort.

What the evidence says

The evidence is inherited from the practice this routine implements. Any duration is allowed; the label shows where you land against the studied dose.

This practice is one way to carry out what the sources on the concept entry (phys.cardio.intensity-zones) studied: aerobic training at different intensities, low-intensity endurance training among them, with cardiorespiratory fitness as the outcome. Nuuttila 2026 (meta-analysis) reports that low-intensity endurance training improved aerobic fitness, with a large effect on relative VO2max (ES 0.94) and small but significant effects on cardiometabolic health. Crowley 2022 (umbrella review, 179 studies) reports small to moderate beneficial effects for HIT over LIT and concludes that the apparent differences between them on VO2max were either small, trivial or inconclusive. Williams 2019 (meta-analysis, 18 studies, 677 participants) reports larger absolute VO2peak gains with high-volume HIIT (0.29 L/min) than with MICT (0.20 L/min) or low-volume HIIT or SIT (0.18 L/min). The full account, source by source, is on the concept entry this practice links to (phys.cardio.intensity-zones).

Key sources

meta-analysisEffectiveness of High-Intensity Interval Training (HIT) and Continuous Endurance Training for VO2max Improvements: A Systematic Review and Meta-Analysis of Controlled TrialsZ. Milanović, G. Sporiš, M. Weston (2015) · Sports Medicine · 10.1007/s40279-015-0365-0 · full text

meta-analysisTraining Mode Comparisons on Cardiorespiratory, Body Composition and Metabolic Profile Adaptations in Reproductive Age Women: A Systemic Review and Meta-AnalysisJ. M. Aparecido, C. S. Frientes, G. L. Martins et al. (2022) · Obesities · 10.3390/obesities2020018 · full text

meta-analysisEffects of Low‐Intensity Endurance Training on Aerobic Fitness and Risk Factors of Cardiometabolic Health in Working‐Age Adults: A Systematic Review and Meta‐AnalysisOlli-Pekka Nuuttila, Pekka Matomäki, J. Raitanen, Harri Sievänen, T. Vasankari (2026) · Scandinavian Journal of Medicine & Science in Sports · 10.1111/sms.70208 · full text

Each source is shown by its own study design.

5 sources: 4 meta-analyses, 1 systematic review

Agreement: consistent for this claim. Direction recorded for 2 of 5 sources; not yet recorded for the rest.
The claim's outcome: Outcome not yet recorded
Certainty: No source states a certainty rating.

What each source measured and concluded (5)

meta-analysis · 2015

Milanović et al. (2015) — Effectiveness of High-Intensity Interval Training (HIT) and Continuous Endurance Training for VO2max Improvements: A Systematic Review and Meta-Analysis of Controlled Trials

What it measured: Maximal oxygen uptake (VO2max)
How it measured it: Laboratory test (typically measured through treadmill test or cycle ergometry)
How it was read: read in full text
What the review says it includes: meta-analysis
Studies and participants, as stated: N = 723 participants across 28 studies

meta-analysis · 2022

Aparecido et al. (2022) — Training Mode Comparisons on Cardiorespiratory, Body Composition and Metabolic Profile Adaptations in Reproductive Age Women: A Systemic Review and Meta-Analysis

What it measured: Cardiorespiratory fitness (CRF), weight (kg), body fat mass (%), plasma glucose (fasting), and lipid levels.
How it measured it: Spirometry for CRF, body composition analysis for weight and body fat, blood samples for glucose and lipid levels. The measurement tools are validated.
How it was read: read in full text
What the review says it includes: meta-analysis, systematic review
Studies and participants, as stated: N = 459 participants across 11 studies

meta-analysis · 2026

Nuuttila et al. (2026) — Effects of Low‐Intensity Endurance Training on Aerobic Fitness and Risk Factors of Cardiometabolic Health in Working‐Age Adults: A Systematic Review and Meta‐Analysis

What it measured: Aerobic fitness (VO2max, VT1), cardiometabolic health indicators (systolic and diastolic blood pressure, cholesterol levels, triglycerides, glucose), body composition (fat mass, fat-and bone-free mass).
How it measured it: VO2max: graded exercise test on a cycling ergometer; Blood pressures: mercury manometer; Blood samples: enzymatic assays; Body composition: DXA and CT scans.
Direction it states for the claim's outcome: Improved
How it was read: read in full text
What the review says it includes: systematic review and meta-analysis
Studies and participants, as stated: Enrolled: N = 120; Analyzed: N = 90

meta-analysis · 2019

Williams et al. (2019) — A Multi-Center Comparison of O2peak Trainability Between Interval Training and Moderate Intensity Continuous Training

What it measured: VO2peak
How it measured it: Indirect calorimetry from a graded exercise test to volitional fatigue on a cycle ergometer or treadmill (validated laboratory test)
How it was read: read in full text
What the review says it includes: meta-analysis
Studies and participants, as stated: N = 677 participants across 18 studies
Heterogeneity, as stated: Heterogeneity of participants and training approaches

systematic review · 2022

Crowley et al. (2022) — The Effect of Exercise Training Intensity on VO2max in Healthy Adults: An Overview of Systematic Reviews and Meta-Analyses

What it measured: VO2max
How it measured it: Laboratory test (validated)
Direction it states for the claim's outcome: Improved
How it was read: read in full text
What the review says it includes: umbrella review (review of reviews)
Studies and participants, as stated: N = not reported participants across 179 studies
Heterogeneity, as stated: Methodological considerations such as heterogeneity, small-study bias, and overlap between studies.

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