5K Base Phase: The Steady Tempo Run

This article is part of our 5K session series. Each article covers one session: how it’s structured, what it does, when to run it, and what to run around it. This one is the first step up from easy running: a steady tempo run with your heart rate kept firmly under control.

The session at a glance

Where it fits: the four phases of 5K training

We split 5K training into four phases. Each has a different job:¹

• Base (6–8 weeks): build your aerobic engine and get your legs used to regular running. Almost everything is easy.
• Build (4–6 weeks): add harder sessions, like threshold intervals, on top of the base.
• Peak (2–3 weeks): sharpen with work at or near 5K race pace.
• Taper (7–10 days): cut the volume, keep a little speed, and arrive at the start line fresh.

The steady tempo run is the hardest session in the base phase, and it’s deliberately not very hard. It bridges the gap between easy running and the threshold intervals that arrive in the build phase.

Steady tempo vs. classic tempo

“Tempo run” means different things to different runners. A classic tempo run is usually run at or around your lactate threshold, the point where lactate starts building up in your blood faster than your body can clear it.² That’s typically zone 4, and it feels comfortably hard.

This session is gentler. It sits below threshold, at the top of your aerobic range: upper zone 2 and into zone 3. Think of it as a controlled steady run rather than a threshold effort. In the base phase that’s what you want, a little more stimulus than an easy run without the recovery cost of true threshold work.

Purpose, goal and target

Purpose: to practice holding a steady, slightly faster rhythm for a sustained period, and to extend your aerobic fitness toward the upper end of your aerobic range.

Goal: 3.7 miles (6km) at an even effort, finishing with your heart rate still under control and feeling you could have run another mile at the same effort.

Target: an effort of 7 out of 10, where short sentences are possible but a full conversation is hard work. Your heart rate should sit at the top of zone 2 and into zone 3; if you need a refresher on setting zones, see how to build an aerobic base. Pace it evenly, so your second half is the same pace as your first, or very slightly quicker.

How to run it

1. Warm up with 5 minutes of brisk walking, then a few minutes of very easy jogging in zone 2.
2. Build gradually into the steady effort over the first half mile (about 1km). Don’t jump straight to the target; let your heart rate rise smoothly.
3. Hold the effort. Settle into a rhythm you could keep for much longer than the session lasts, and check your heart rate every few minutes.
4. Control your heart rate. It will creep up slowly over the run, which is normal and is called cardiac drift.³ If it moves into zone 4, ease off slightly until it drops back into zone 3.
5. Finish with a few minutes of easy jogging or walking to bring your heart rate down.

The 3.7 miles (6km) includes the gradual build at the start. For beginners, it’s fine to run the first mile in zone 2 and only lift into zone 3 for the middle section of the run.

What it does to your body

Running at the top of your aerobic range challenges your heart and muscles a little more than easy running, while still relying mostly on oxygen for energy, so it extends your aerobic fitness. Steady running just below threshold also helps your body get better at clearing lactate, which gradually pushes your threshold up.²

It teaches pacing, too. Holding an even effort is a skill, and it’s the skill that decides most 5K races: runners who go out too fast and fade almost always run slower than those who pace evenly. Staying focused on a steady effort for 30–45 minutes is also good practice for concentrating through the middle of a race.

A word of caution about zone 3. It’s the zone most runners drift into on every run without meaning to. As one planned session a week, it’s useful. As your default pace for every run, it becomes the “moderate trap”: too hard to recover from quickly and too easy to be proper speed work.⁴ Keep it to this session.

Timing

Run it once a week at most in the base phase. Beginners can hold off for the first 2–3 weeks and run an easy run instead. Mid-week works well, with an easy day or rest either side.

Avoid the hottest part of the day, because heat pushes heart rate up and makes zone 3 much harder to hold.³ Pick a flat or gently rolling route, since hills make an even effort very hard to control.

Keep the distance at 3.7 miles (6km) and let the pace at the same heart rate come to you over the weeks. In the build phase, threshold intervals usually take this session’s place as the hard run of the week.

Matching sessions

In the base phase, the steady tempo run sits alongside the 3.1-mile (5km) easy run with strides and the 4.3-mile (7km) zone 2 easy run:

Two days after the strides session and two days before the longest easy run, the steady tempo run has room on both sides. That spacing keeps about 80% of your week easy, in line with what the evidence supports.^{4, 5}

Back-to-back: the day before and the day after

The day before: rest or an easy run is best, and the easy run with strides 1–2 days before is ideal. Avoid another hard or long session, because tired legs make it hard to hold a steady effort without your heart rate climbing.

The day after: rest or active recovery, like walking or easy cycling, is best. A zone 2 easy run is fine if you keep it easy. Avoid another session in zone 3 or above: research on heart rate recovery shows the body takes noticeably longer to recover from efforts above the top of zone 2 than from easy running,⁶ so don’t stack them. And look after the basics. A good night’s sleep does more for recovery than any gadget; see sleep and running performance.

Common mistakes

• Turning it into a race. 7 out of 10 means controlled, and if you finish exhausted, it was too hard.
• Starting too fast. Build into the effort; a fast first mile almost always means a slow, painful last one.
• Ignoring heart rate drift. Ease off as your heart rate creeps up, rather than holding the pace and ending up in zone 4.
• Running every run like this. One steady run a week is a session. Every run at this effort is a mistake.
• Choosing a hilly route, which turns a steady run into an uneven one.

Keeping the steady run steady

This session is 3.7 miles (6km) at 7 out of 10, with your heart rate in upper zone 2 and zone 3. It’s a steady run below threshold, gentler than a classic tempo run, and still the hardest session of the base phase. It builds aerobic fitness, lactate clearance and pacing skill. Build into it gradually, pace evenly, and ease off if you drift into zone 4. Run it once a week, with easy days or rest on either side.

This article is general information, not medical or coaching advice. If you feel chest pain, dizziness or unusual breathlessness while running, stop and talk to a doctor.

References

1. Issurin VB. New horizons for the methodology and physiology of training periodization. Sports Medicine, 2010. doi.org
2. Faude O, Kindermann W, Meyer T. Lactate threshold concepts: how valid are they? Sports Medicine, 2009. doi.org
3. Coyle EF, González-Alonso J. Cardiovascular drift during prolonged exercise: new perspectives. Exercise and Sport Sciences Reviews, 2001. doi.org
4. Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance, 2010. doi.org
5. Esteve-Lanao J et al. Impact of training intensity distribution on performance in endurance athletes. Journal of Strength and Conditioning Research, 2007. doi.org
6. Seiler S, Haugen O, Kuffel E. Autonomic recovery after exercise in trained athletes: intensity and duration effects. Medicine & Science in Sports & Exercise, 2007. doi.org