Most runners reach a point where simply running more stops delivering results. You’re consistent, you’re ticking off miles, but your pace hasn’t changed, or races feel harder than they should.
This is usually where interval training comes in.
Interval training introduces controlled bouts of faster running into your week, helping your body adapt to higher speeds and greater effort without needing to run hard all the time. It’s one of the most effective ways to improve fitness, efficiency, and race performance, when used correctly.
What is interval training?
Interval training is a structured style of running that alternates between periods of harder effort and planned recovery. Rather than running at one steady pace from start to finish, the session is broken into repeats, where you run faster for a short time, then ease off before starting the next effort.
Those faster sections are known as intervals, and they’re deliberately challenging, but not all-out sprints. The recovery periods, which might be an easy jog, a brisk walk, or sometimes complete rest, are just as important as the running itself. This cycle of effort and recovery is repeated multiple times within a single workout.
The goal of interval training isn’t to exhaust yourself as quickly as possible. Instead, it’s to run at an intensity you couldn’t sustain continuously, but can repeat with consistency. In its simplest form, interval training comes down to one principle: work hard, recover well, and repeat with control.
Why interval training works
Easy, steady running is excellent for building endurance, but on its own it doesn’t fully prepare your body to cope with faster speeds or higher effort levels. Interval training fills that gap by applying short, focused stress to your system.
When you run harder than your usual pace, even briefly, your body is forced to adapt. Over time, this improves how efficiently you use oxygen, how well you tolerate elevated heart rates, and how effectively your muscles produce force. It also helps you maintain good running form when the pace increases, which is crucial for racing and harder training sessions.
The result isn’t just the ability to run faster for short bursts, it’s becoming a more efficient runner overall, even when you return to easier paces.
Interval training vs steady running
Both steady running and interval training play important roles in a well-balanced plan, but they serve different purposes.
Easy runs primarily develop aerobic endurance and support recovery between harder sessions. Interval sessions, on the other hand, target speed, power, and your ability to sustain higher intensities.
If every run you do feels roughly the same, your body has little reason to adapt, and progress often slows. Interval training introduces contrast into your week, and it’s that contrast that drives improvement.
Can beginners do interval training?
Yes, and many beginners already do, often without realising it.
Run/walk sessions, which appear in many early-stage plans, are a basic form of interval training. The main difference as you progress is intensity. For beginners, “hard” simply means running a bit faster than normal, not hitting a specific pace.
Recovery periods can still involve walking, intervals remain short and controlled, and the overall structure stays simple. As fitness improves, the running sections gradually become longer or quicker, while recoveries shorten, but the underlying format doesn’t change.
How often should you do interval training?
Because interval sessions are physically demanding, doing them more often doesn’t necessarily lead to better results.
For most runners, one interval session per week is enough to stimulate progress. More experienced runners, particularly those training for races, may include two sessions per week, but hard workouts should never be done on consecutive days.
Easy running between interval sessions is what allows your body to absorb the training and adapt. Without that recovery, the benefits are reduced and the risk of injury increases.
How hard should an interval feel?
Interval training isn’t about hitting a precise pace, it’s about effort. The right intensity depends on the length of the interval.
Short intervals of 30 to 60 seconds should feel very hard but still controlled. Medium-length intervals of two to three minutes are uncomfortable but sustainable, while longer intervals of four to six minutes feel hard, steady, and require focus rather than aggression.
A good rule of thumb is consistency. You should finish each interval confident that you can complete the next one at a similar quality. If your pace drops dramatically, the effort is likely too high.
Recovery: the most overlooked part of interval training
Recovery isn’t wasted time, it’s what makes interval training effective in the first place.
During recovery periods, your heart rate drops, your muscles begin to clear fatigue, and your body prepares for the next hard effort. Recovery might involve easy jogging, brisk walking, or standing still during particularly demanding sessions.
The aim isn’t to recover completely, but to recover enough so that each interval can be run well.
Types of interval training
Interval sessions can be adapted depending on what you’re training for. Short intervals tend to focus on speed and running economy, while longer intervals are better suited to building race-specific endurance. Hill intervals add strength and power, and progressive intervals help develop pacing control.
This flexibility is why interval training appears in plans for everything from 5Ks through to marathons, it can be shaped to suit almost any goal when used thoughtfully.
- Short intervals: Short bursts of fast running, typically lasting between 20 seconds and one minute, with relatively generous recovery. These sessions focus on improving leg speed, running economy, and your ability to run fast with good form. Because the intervals are brief, the pace is usually quite high, but the overall volume is low.
- Long intervals: Longer efforts, usually ranging from two to six minutes, run at a challenging but controlled pace. These intervals are designed to build endurance at speed and are particularly useful for 5K, 10K, and half marathon training. The effort feels uncomfortable but sustainable, with the aim of keeping pace consistent across all repetitions.
- Hill intervals: Intervals run uphill, often lasting 20 seconds to two minutes, with easy jog or walk recoveries downhill. Hill work develops strength, power, and running-specific muscle resilience while naturally limiting speed, which can reduce impact stress. They’re especially effective for improving form and building confidence on varied terrain.
- VO₂ max intervals: High-intensity intervals run near your maximum aerobic capacity, usually lasting two to four minutes with equal or slightly longer recovery. These sessions are demanding but effective at improving how much oxygen your body can use at higher speeds, making race paces feel more manageable over time.
- Tempo intervals: Intervals run at a “comfortably hard” pace, often close to threshold intensity, broken into manageable chunks with short recoveries. Instead of one long tempo run, these sessions allow you to accumulate quality time at pace while maintaining better form and control.
- Pyramid intervals: A structured session where interval length increases step by step, then decreases again (for example: 1–2–3–4–3–2–1 minutes). Pyramids challenge pacing awareness and mental focus, as each interval feels different but needs to be executed with control rather than intensity spikes.
- Progressive intervals: Intervals that gradually increase in pace as the session goes on. Early reps feel controlled, while later ones are harder but still sustainable. These sessions teach strong finishing and pacing discipline, helping runners avoid starting too fast and fading.
- Fartlek intervals: Unstructured intervals that mix faster and slower running based on feel, landmarks, or terrain rather than strict timings. Fartlek sessions improve speed and adaptability while keeping training mentally fresh, making them especially useful during base training phases.
A simple beginner interval session
If you’re new to intervals, start small:
- 10-minute easy warm-up
- Run hard for 30 seconds
- Walk or jog easily for 90 seconds
- Repeat 6–8 times
- 5–10 minute cooldown
The session should feel challenging but manageable, not exhausting.
The bottom line
Interval training is a structured way to run faster for short periods, recover, and repeat, helping you build speed, strength, and efficiency. When used sparingly and intelligently, it’s one of the most powerful tools a runner can use.
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