Zone 2 and Base Endurance for Hyrox

What is zone 2

Zone 2 is a moderate effort level, usually around 60 to 70% of maximum heart rate. Exact values vary from person to person: the most reliable guide remains the talk test. If you can speak in full sentences while breathing calmly, you are in the right zone. If you can only manage a few words, it is too hard.

On a perceived-effort scale from 1 to 10, zone 2 feels like a 3 or 4: you feel able to keep going for a long time.

Why it matters for Hyrox

• A solid aerobic base: your 8 kilometres of running depend mostly on endurance. The wider your base, the steadier you stay from one kilometre to the next.
• Better recovery between stations: an efficient aerobic engine brings your heart rate down faster when you leave a hard station.
• Volume without excessive fatigue: you accumulate training hours without exhausting your nervous system, which leaves you fresh for strength and intensity sessions.
• Lower injury risk: running at moderate intensity reduces repeated high-intensity impact.

How much and how often

For most athletes, 2 sessions of 40 to 60 minutes per week are enough to start. Over time you can move to 3 sessions or lengthen one session to 75 minutes. A large share of your weekly cardio volume, often the majority, should stay at easy intensity. The rest goes to harder sessions and race-specific combinations.

Which exercises to use

• Running: the foundation, since it is half of your race time.
• Bike or rowing: perfect for building volume with less impact.
• SkiErg at easy intensity: to practise technique without excessive fatigue.
• Brisk uphill walking: useful when returning to training or managing a niggle.

Alternating machines varies the stimulus and protects your joints. To fit this work into a full week, read our guide on Hyrox training frequency.

Mistakes to avoid

• Going too fast: the "grey zone", neither easy nor truly hard, tires you without building either base or speed.
• Relying only on your watch: default estimated zones are approximate. Cross-check them with the talk test. See our article on the smartwatch for Hyrox.
• Neglecting consistency: zone 2 pays off over several weeks, not in a single session.
• Dropping it before the race: keep it until the taper, simply reducing the volume.

How to track progress

A good indicator: at the same heart rate or the same perceived effort, your pace improves over the weeks. You can check it with the same easy 5 km route every 4 weeks, noting pace and feel. It fits naturally alongside your fitness tests.

Estimating your heart rate and zones

If you use a watch, a very simple way to estimate maximum heart rate is to subtract your age from 220. This calculation remains approximate: individual variation can exceed 10 beats per minute. Use it as a starting point, then adjust with the talk test and your feel. Zone 2 then sits around 60 to 70% of that value.

Another useful approach: a progressive-effort session where you note the heart rate at which you can no longer hold a full sentence. Your zone 2 sits just below that conversation threshold.

Sample zone 2 sessions

• 40-minute continuous run: comfortable pace, calm breathing, full sentences possible. Perfect to start.
• 60-minute mixed session: 20 minutes rowing, 20 minutes cycling, 20 minutes running. Changing machine reduces joint fatigue.
• Machine rotation in 3 blocks: 3 × 15 minutes (SkiErg, rower, bike) with 2 minutes of transition. It also develops technique.
• 75 to 90-minute long session: once every 1 to 2 weeks in the base period, on flat or gently rolling terrain.

A typical week with zone 2

Here is a sample 5-session week that includes base endurance without sacrificing strength:

Find more complete distribution rules in our guide to training frequency and season periodization.

Zone 2 and strength: do not sacrifice one for the other

Many athletes fear that endurance gets in the way of strength. In practice, well-dosed zone 2 interferes little with strength gains, as long as you do not add too much volume at once. Place strength sessions before, or several hours apart from, your endurance sessions when possible, and increase zone 2 volume in steps of about 10% per week. Our article on strength training for Hyrox details how to organise strength without losing endurance.

Adapting zone 2 to conditions

• Heat: heart rate rises faster at the same effort. Slow down to stay in the zone instead of following your usual pace.
• Fatigue or poor sleep: your heart rate may be higher than usual. In that case, rely on feel and the talk test.
• Hills: uphill, slow down clearly or walk briskly. The goal is not speed but time at controlled intensity.
• Returning after a break: start with sessions of 20 to 30 minutes and increase gradually.

A word on patience

Zone 2 is frustrating at first: you feel like you are moving slowly, or doing nothing. That is normal. It is also why many quit too early. The benefits show up gradually: you recover faster, hold pace longer and link intensity sessions with more quality. Three to four weeks of consistency are usually enough to feel a first difference.

Zone 2 and race preparation

As the race approaches, zone 2 does not disappear: it maintains the base while reducing fatigue. In the last two weeks, keep one or two shorter easy outings, for example 30 to 40 minutes, to stay active without draining your reserves. After the race, it is also an excellent active-recovery tool: a very easy 20 to 30 minute outing in the following days helps restart circulation without major mechanical stress. Built into the whole year, it becomes one of the most reliable foundations of your progress.

Common zone 2 mistakes

• Going too hard: the most frequent mistake. If you cannot hold a sentence, you are above zone 2.
• Trusting the watch blindly: optical sensors can lag or drift. Combine the numbers with how you feel.
• Doing it only when you have time: zone 2 works through repetition; place it in your week like any other session.
• Judging it by one session: you will not feel the effect after a single outing. Look at your pace at the same heart rate every 4 weeks.
• Forgetting recovery: easy does not mean free. Keep rest days and watch your sleep.

A simple benchmark helps: run 30 minutes at the same heart rate every month and note the distance covered. If it grows, your base is improving even when intensity sessions feel unchanged.

Frequently asked questions

This content is provided for information only and does not replace the advice of a healthcare professional. ZONE8 is an independent service, not affiliated with HYROX®.