How to Do Interval Running, Part 2: Warm-Up, Recovery, and Avoiding Mistakes

The safest way to do interval running is to spend five to ten minutes running easily, then do dynamic stretching (moving stretches that copy the motions of running) before every session. Below: the warm-up in detail, the signs you are overdoing it, cooling down, the best terrain, how to fit intervals into your weekly routine, and the common mistakes that undo otherwise good training.

Most interval sessions that go badly were decided before the first fast effort. I see runners go from the car straight to full effort far too often, and it rarely ends well. If you haven't read it yet, start with How to Do Interval Running Part 1 for how to structure a session, then come back here for everything that surrounds it.

The Right Warming Up for an Interval Workout

When you're heading into a hard workout — intervals or tempo runs — you need to warm up properly. A good warm-up gradually prepares your body for the high-intensity work ahead, and it cuts your injury risk. That's two very good reasons to never skip it.

So follow my lead — this is the warm-up routine I use myself. Start with five to ten minutes of easy running. This raises your heart rate, pumps more oxygen to your muscles, and loosens your joints before you ask them to work hard.

After your easy running, move into dynamic stretching — targeting the key muscle groups you'll rely on: hip flexors, glutes, hamstrings, and calves. Unlike static stretching, dynamic stretching mimics the actual motions of running, which makes it far more suitable before a hard session.

For more detail on this warm-up, check out my page on running stretches.

The Signs of Overexertion when Doing an Interval Workout

When you're new to intervals, it's easy to push too fast. I'd strongly recommend you learn to recognise the signs of overexertion — and if they show up, cut your workout short. No heroics needed.

The common signs to watch for are:

A severe drop in speed.

Inability to finish the interval.

Breathlessness and dizziness.

Listen to your body — it will tell you when enough is enough. If your heart rate isn't recovering during rest intervals, that's another warning sign worth taking seriously. A heart rate monitor makes this easy to track. My advice to you: build up your mileage and your interval training progressively, week by week.

Let those first few weeks of intervals feel a little easy. There's real satisfaction in finishing a session feeling like you had a little more left in the tank — I'd take that over digging too deep every time.

Cooling Down after Interval Running

Never finish your workout on a fast interval. A 5–10 minute easy jog after your last rep is far better than stopping dead — it brings your heart rate and breathing down gradually instead of abruptly. (Don't expect it to prevent next-day soreness — the evidence for that is weak. It just makes finishing feel better.) If you're really tired, replace the jog with a walk. That's fine. That's correct.

After your run, add some static stretches as explained on the running stretches page. This helps reduce muscle tension and improve flexibility — a small investment that pays off over time.

Best Terrain for Intervals

Without a doubt, the best place to do intervals is on flat, even surfaces. An athletics track is ideal if you have access to one — but if you don't, that's absolutely fine too.

Find a path that's quiet, free of traffic lights, and clear of crossings. Somewhere you're not having to weave past pedestrians or watch for cars. When you've created those conditions for yourself, you have the best possible control over your effort in each interval. Simple as that.

You can do intervals on hills too — and if you're training for a hilly trail race or mountain ultra, running your intervals on hills makes complete sense. But I'm assuming most of you are running for fitness, for weight loss, or for a local 5k, half marathon, or marathon. For you, flat surfaces are the sensible choice.

How to Incorporate Intervals into Your Weekly Routine

When you're starting out, you're probably doing 3–4 runs per week — and your focus should be on building a strong endurance base. The majority of your running should be slow and easy.

So my recommendation is this: do a maximum of one session per week that's faster than easy running. One interval session is plenty when you're starting out.

Once your body adapts, you can gradually build up to two hard sessions per week — with ample recovery time in between. Balance your interval training with relaxed, easier, and longer runs.

How much recovery you need between sessions, and how to tell when you're ready to add a second one, is covered in Recovery Between Interval Running Sessions.

Common Mistakes When Doing Interval Workouts

Let's go through the mistakes I see most often — and how you can sidestep them.

Too Fast
The most common mistake is going out too hard in the early intervals. You'll pay for it midway through — either by fading badly or picking up a niggle. Start conservatively and build.

Skipping Recovery Time
Skipping the rest between hard intervals is another trap. That recovery period is as important as the fast interval itself — it lets your heart rate drop and your body reset before the next effort. Don't cut it short.

Too Many Hard Workouts in a Week
Running at fast paces across all your weekly sessions leads to overtraining and stalled performance. Many of us — when we first start running — run our easy runs too fast. The result? We arrive at our interval sessions already tired, and the intervals suffer for it.

Keep a sensible balance between hard and easy running in your weekly schedule. The easy days exist for a reason.

Forgetting to Warm Up and Cool Down
Skipping your warm-up or cool-down — as covered above — is a mistake that catches up with you. These aren't optional extras. They prepare your body for the work and help it recover afterwards. Do both, every time.

Trying to Keep Up With Faster Runners
If you're running with a group and you're new to intervals, you may feel the pull to match the pace of more experienced runners. Beware. Everyone has their own pace — and running at someone else's will only increase your injury risk and undermine your session. Run at a pace that's right for your fitness level. Full stop.

Chasing GPS Pace Over Effort
On hilly, windy, or trail terrain, the pace on your watch can mislead you — the number says you've slowed, but the effort tells a different story. Your breathing, your effort level, and your heart rate if you're tracking it — these are the more reliable guides to whether a rep was run at the right intensity. Don't let a pace figure push you harder than the terrain warrants.

Go Further: The Interval Training Workout Library

This page is part of the full interval training library. For more:

• Interval Running Workouts: The Complete Training Guide — the pillar anchor, with the full menu of workouts
• Recovery Between Interval Running Sessions — how much rest you need between hard sessions
• Choosing Interval Workouts by Training Phase — for when you're ready to move past the beginner-frequency guidance above

Conclusion and Further Recommended Reading

Interval running — done right — will genuinely boost your running performance. Whether you're adding interval sessions, fartlek workouts, or other hard runs into your week, keep the guidance on this page in mind.

Listen to your body, warm up properly, choose suitable terrain, spot the signs of overexertion early, cool down, and fit your intervals sensibly into your weekly schedule. Do all of that, and you'll keep improving without raising your injury risk or losing your enjoyment of running.

Steady progression is what keeps this sustainable — and enjoyable — over the long run.

Oh, and if you missed Part 1, follow the link: How to Do Interval Running Part 1.

For a deeper guide to avoiding interval mistakes and setting the right paces, I recommend Daniels Running Formula by coach Jack Daniels.

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