{ "slug": "vo2-intervals", "name": "VO2 intervals", "aliases": [ "vo2 max intervals", "norwegian 4x4", "4x4", "speed work", "track intervals", "zone 5", "VO2 max intervals", "Norwegian 4x4", "vo2-intervals" ], "family": "run", "heat": "mid", "talk": "Some talk", "mostDiscussed": false, "firstLine": "VO2 intervals are repeated hard aerobic efforts separated by easier recovery. They aim to improve how much oxygen your body can use during demanding exercise. The workout is different from a VO2-max number estimated by a watch.", "whyLine": "VO2 intervals are repeated hard aerobic efforts separated by easier recovery. They aim to improve how much oxygen your body can use during demanding exercise. The workout is different from a VO2-max number estimated by a watch.", "feelWords": [ "VO2", "4x4", "intervals", "gasping", "track" ], "commonPicture": [ { "lead": "4 × 4 example: 4 minutes hard, then 3 minutes easy", "why": "Four work periods contain 16 hard minutes; warm-up examples add 10–20 easy minutes. [community]" }, { "lead": "Shorter examples: 6–10 repeats of 1–2 minutes", "why": "Easy recoveries are equal or longer in these reports. [community]" }, { "lead": "The effort needs to be repeatable", "why": "People compare sustained pace or power across repeats; one hard session weekly is one arrangement. [community]" } ], "watchFor": "Four interval days. Starting here as a new runner. Racing the recoveries.", "whatPeopleSay": [ "**The job:** spend repeated bouts at a high output. VO₂ refers to oxygen consumption; “VO₂ max” is maximum oxygen-use capacity. [community]", "**Peter Attia / Norwegian 4×4** made this a 2020s brand. The session is older than the podcast. [community]", "**r/running 2026** still argues Zone 2 vs intervals. Hybrid weeks keep both. [community]", "**The session details are the work and recovery bouts:** their length and repeatable effort describe more than the interval label alone. [community]", "**New runners do not need this.** C25K and easy miles first. [community]", "**Why people get hurt:** they do intervals on tired legs after a long run, or they do them daily. [community]", "**Bike / rower 4×4** is easier on joints and easier to keep honest. [community]", "**Track nights** are social and too fast. Ego lives in lane 2. [community]", "**Hyrox people** sometimes think stations replace this. They do not replace easy miles either. [community]", "**Watch “VO2 max” scores** are noisy. The session is not for a ring to go up tomorrow. [community]", "**It should not be a race.** If they vomit, they went looking for a story. [community]" ], "howPeopleRunIt": [ "**One day.** They write it on the calendar so they do not add a second. [community]", "**Warm up** until they feel like they could jog forever. [community]", "**Hard bouts at a pace they can repeat** — not a first-rep hero sprint. [community]", "**Recoveries are easy.** Jog or walk. Not a tempo. [community]", "**They stop** if form or a joint falls apart. [community]", "**Easy next day.** Walks fine. Another quality session not fine. [community]", "**Heat / bad sleep:** they skip or cut to 2–3 bouts. [community]" ], "amountsPeopleUse": [ "**4×4:** **4 min** hard / **3 min** easy × **4**. [community]", "**Shorter:** **6–10 × 1–2 min** hard with equal or longer easy. [community]", "**Days:** **1** a week for hobby people. [community]", "**Warm-up:** **10–20 minutes** easy. [community]", "**Total hard time:** often **12–20 minutes**, not 40. [community]" ], "howPeopleKeepIt": [ "**A hill or a bike** so pace ego is quieter. [community]", "**A partner who will not turn it into a race.** [community]", "**They skip it** during a cut that already feels awful. [community]", "**They keep easy miles** as 80% of the week. [community]", "**A deload week** without intervals every few weeks. [community]" ], "howItFeels": [ "**Rep 1:** too fast if they are normal. [community]", "**Rep 3:** this is the workout. [community]", "**Rep 4:** character. Or they already blew it on rep 1. [community]", "**After:** legs heavy, mood oddly good. [community]", "**Next day:** a little wrecked. Easy only. [community]", "**A good block:** 5K pace feels less like panic. Easy pace may drop too. [community]" ], "howLongPeopleRunIt": [ "**In a race block,** once a week for 4–8 weeks. [community]", "**Off-season:** they may drop it and only go easy. [community]", "**It is not a 28-day identity.** [community]", "**After 40:** shorter, fewer, more warmup. [community]" ], "deepDive": [ "**Tempo is comfortably hard. This is hard.** Different days. [community]", "**Easy miles pay the bill.** Intervals without a base is junk tired. [community]", "**Norwegian 4×4** is one recipe. Hills and bikes count. [community]", "**Hyrox** still wants this plus sled practice. See HYROX. [community]", "**Kids / true beginners:** no. [community]" ], "watchForLong": [ "**Not a first-month runner session.** [community]", "**Not four times a week.** [community]", "**Do not race the recoveries.** [community]", "**Chest pain, wheeze, fainting:** person and clinician. [community]", "**A watch VO2 number is not a diagnosis or a goal.** [community]" ], "related": [ "hard-cardio-day", "easy-miles", "tempo-run", "hyrox-race", "rest-days" ], "researchPointer": [], "housePointers": [ { "href": "/fit/#hard-cardio-day", "label": "STUDfit · One hard cardio day" }, { "href": "/self/#vo2-number", "label": "STUDself · VO2 as a number" } ], "playPointer": null, "sources": [ "r/running interval threads", "Norwegian 4×4 / Attia-shaped talk", "r/PeterAttia" ], "disclaimer": "Community talk may be wrong. Not medical, training, or diet advice. Sharp pain, fainting, or disordered-eating concerns need a clinician.", "quickAnswerHistory": [ { "field": "commonPicture", "rows": [ { "lead": "Norwegian 4×4", "why": "4 minutes hard, 3 minutes easy, four times. Attia-adjacent and r/running both say the name. [community]" }, { "lead": "Or shorter repeats", "why": "8×400, 5×800, hill sprints — same job, different costume. [community]" }, { "lead": "Long warmup", "why": "10–15 minutes easy plus strides. The first interval is not the warmup. [community]" } ] }, { "field": "firstLine", "rows": [ "VO2 work is the short, hard repeats — 4×4 hills, track 800s, bike intervals — then they go easy again." ] }, { "field": "whyLine", "rows": [ "VO2 work is the short, hard repeats — 4×4 hills, track 800s, bike intervals — then they go easy again." ] }, { "field": "commonPicture", "rows": [ { "lead": "4 × 4 minutes hard, with 3 minutes easy between", "why": "The four repeats contain 16 total hard minutes. [community]" }, { "lead": "Shorter option: 6–10 × 1–2 minutes hard", "why": "The examples use equal or longer easy recoveries. [community]" }, { "lead": "Once a week", "why": "Next to easy miles, not instead. [community]" }, { "lead": "Hard but controlled", "why": "Last repeat looks like the first. That is the skill. [community]" }, { "lead": "Warm-up: 10–20 easy minutes", "why": "The shorter-repeat and 4×4 versions are both described below. [community]" } ] }, { "field": "whatPeopleSay", "rows": [ "**The job:** A little time at a high output so the easy week has a ceiling to push. [community]", "**Self has VO2 / hard-cardio habit cards.** Fit owns the session. [community]" ] } ] }