One of my fondest memories of running was going to train at the local grass football pitch as a young boy. The coach would have us run a series of sprints along the length of the pitch, then run slowly across the width.
At the time, I had no idea we were practicing a well-established training method known as interval running. Interval training alternates bursts of high-intensity running with periods of lower-intensity running, walking, or rest.
Back then, it just felt like fun. But far from those green football fields in Ireland, this same technique has been a cornerstone of training for the world’s elite runners—and for good reason. Numerous studies have shown that interval training is one of the most effective ways to improve speed, endurance, and race-day performance.1Engel, F. A., Ackermann, A., Chtourou, H., & Sperlich, B. (2018). High-Intensity Interval Training Performed by Young Athletes: A Systematic Review and Meta-Analysis. Frontiers in Physiology, 9. https://doi.org/10.3389/fphys.2018.01012
If you’ve hit a plateau with your running or are chasing a new personal best, adding interval training to your routine might be the game-changer you need.
In this guide, we’ll break down the key benefits of interval training, how to structure your workouts, ideal recovery intervals, and a few sample sessions to get you started.
Why Interval Training Works
Designed in the 1930s by German coach Waldemar Gerschler and physiologist Hans Reindell, it was only at the 1952 Olympic Games that Czech athlete Emil Zatopek attributed his three gold medals to interval training, and the benefits of this method were recognized.
If performed consistently and correctly, interval training can provide substantial physiological and mental benefits. However, if you are new to this type of training, ease into it, as it can put a lot of stress on the body.
#1: Improves Cardiovascular Endurance
One of the main benefits of interval training is an increase in aerobic capacity.
The most widely used term in sports science for an athlete’s aerobic capacity is VO2 max. It is defined as the maximum rate of oxygen consumption during incremental exercise and indicates how efficiently an individual uses oxygen during exercise.
When coupled with continuous steady running, interval training can give you a real boost in cardiovascular fitness.
Your heart will become stronger and more efficient, leading to increased maximum stroke volume and cardiac output. Thus, in short, interval training will allow you to increase the amount of blood that you can pump per beat.
Other research on interval training indicates a reduced risk of heart disease and high blood pressure.2Preparing to download … (2025). Nih.gov. https://pmc.ncbi.nlm.nih.gov/articles/PMC6203095/pdf/rmdopen-2018-000729.pdf
#2: Boosts Anaerobic Power
As we have learned, the body’s ability to continuously supply muscles with adequate levels of oxygen is a key determinant of their performance. However, a common limiting factor in an athlete’s ability to improve is often due to an underdeveloped anaerobic capacity.
By training at paces faster than those associated with your aerobic capacity, you’ll improve your body’s ability to delay the onset of lactic acid and better handle its effects.
To do this in a controlled manner and to apply a careful approach, it is important to know your pace.
Related: Marathon Pace Guide: How To Determine It + Race Pace Strategy and Running Pace Calculator.
During the 1960s, Frank Horwill, the highly accomplished British endurance coach, studied the work of the Nobel Prize-winning physiologist A.V. Hill and later devised a system to define the aerobic-to-anaerobic ratio for common running paces.
Related: Aerobic vs Anaerobic Training: Why You Need Both in Your Running Plan
He indicated that aerobic running ranges from jogging (100% aerobic) to 3km speed (60% aerobic). Similarly, anaerobic running starts with 200m (95% anaerobic) and extends to 1,500m speed (50% anaerobic).
For example, running at speeds quicker than 1,500m pace is considered more anaerobic than aerobic. Running at 800m is regarded as 67% anaerobic, and 400m pace is 83% anaerobic, whereas 3km pace is considered 60:40 aerobic to anaerobic.
The table below summarizes the aerobic-to-anaerobic ratio for common running paces.
| Pace | Aerobic (%) | Anaerobic (%) | Category |
| Jogging | 100 | 0 | Aerobic |
| Half marathon | 94 | 6 | Aerobic |
| 10km | 90 | 10 | Aerobic |
| 5km | 80 | 20 | Aerobic |
| 3km | 60 | 40 | Aerobic |
| 1500m | 50 | 50 | Aerobic |
| 800m | 33 | 67 | Anaerobic |
| 400m | 17 | 83 | Anaerobic |
| 200m | 5 | 95 | Anaerobic |
#3: Keeps Training Fresh And Exciting
If all your training involves steady, continuous running, you may feel that it has become a little monotonous.
By adding some interval running sessions to your weekly schedule, you should get a new lease of life, increase motivation, and improve your performance.
Plus, studies show that short bursts of intense movement and exercise stimulate a greater release of feel-good endorphins, such as serotonin and dopamine, making interval training more enjoyable.3Ghafarian Sarkandi, Fateme, Gaieni, A., Rajabi, H., Aboutaleb, N., & Kordi, M. (2018). High-Intensity Interval Training Improved the Expression of Serotonin and Brain Derived Neurotropic Factor in Myocardial Infarction Rats. Sport Physiology & Management Investigations, 10(3), 157–168. https://www.sportrc.ir/article_80656_en.html
Start by replacing one of your regular steady runs with an interval training session, and gradually allow your body to adapt to the new stimulus.
#4: Efficient For Those With A Busy Schedule
Multiple studies compare intense interval running with moderate continuous running, and each shows that, within the same period of training, far greater improvements are achieved with interval running.4Nishimura, J. (1996). Medicine & Science in Sports & Exercise Issue, 28(10), 1327–1330. https://deliberateperformance.ca/wp-content/uploads/2011/01/effects-of-moderate-intensity-endurance-and-high-intensity-intermittent-training-on-anaerobic-capacity-and-e280a2vo2max.pdf
This makes interval training a great option for those who find it difficult to fit in their training around other life and work commitments.
The first man to run under 4 minutes in the mile, Roger Bannister, used interval training effectively in the 1950s, squeezing in his 10 x 400m repeats during his lunch breaks from his arduous, time-consuming medical studies.
That said, it is important not to overload your body by turning all your training runs into time-efficient interval sessions. They are there to complement your steady aerobic running, which should always make up most of your weekly training.
As Frank Horwill notes: “The world’s leading work physiologists agree that only about one-third of the total weekly training distance should be devoted to working between 80 and 100 percent of VO2 max.”
How To Incorporate Interval Training Into Your Plan
People who are not used to intervals often get overly excited and start too fast in their first sessions, so they frequently have to quit in the middle of a workout from exhaustion.
It’s important to incorporate intervals into your training routine gradually. I’d recommend you start by replacing one of your normal steady runs with an interval session and build up slowly from there.
Remember that when you run at higher intensities and speeds, you’ll put more stress on your body. To minimize the overall burden or stress on the body, you should always consider the following points:
- By adjusting the duration of the interval, intensity, and recovery periods
- By wisely selecting the total number of intervals
It is important to note that the quicker the pace, the longer the recovery you’ll need to maintain the required times for each interval. Running at a 10km pace for a 5-minute interval feels very different from running an 800m pace over a 45-second interval.
Imagine that you have a target of running 20 minutes for the 5k distance. This would equate to a 4.00 minutes/km pace that you’ll need to sustain over the whole distance.
Start with intervals at your target race pace—5km pace. This could be 6 x 800m at 3.12 (as 5k pace is 96 seconds per 400m), with a 2-minute recovery between intervals.
Then you could try running at a speed quicker than race distance, 3k pace, for instance.
The 3k is 3.50 minutes/km (6.08 minutes/mile) or 92 seconds per 400m. A good initial session is to run 8-12 repetitions of 400m in 92 seconds with a 92-second recovery.
Then the next stage in your speed adaptation is to run intervals at a target 1500m pace of 88 seconds per 400m (3.40 minutes/km or 5.52 minutes/mile).
Here, you should aim to run 6-10 repetitions of 400m with a 90-second recovery. If this is too difficult, reduce the interval to 200m and run it 10-12 times with the same recovery.
How Much Rest Should I Take In Between Reps?
One of the biggest mistakes people make with interval training is choosing the wrong intensity or not taking enough time to recover between intervals.
New runners should start with aerobic intervals with a work-to-rest ratio of 1:2.
As you get more comfortable with the training, you could then apply the usually recommended ratios of 1:0.5-1 for slower aerobic paces and 1:2-2.5 for faster anaerobic paces (see table 1).
For example, if you are starting with intervals in the aerobic range, you’ll be able to take a recovery around 50% of the interval’s duration.
For instance, if you were performing five 1500m intervals at 10k pace, you could take three minutes of recovery. Then, as you get fitter, you can gradually reduce recovery time while still focusing on maintaining the pace.
However, if you have a session of very fast anaerobic intervals, you’ll need a much longer recovery than the duration of the interval. For instance, if running 8 x 200m @ 800m pace in 44 seconds, then you would be advised to take a 2-minute recovery.
Remember, the switch from aerobic to anaerobic will require you to engage your fast-twitch fibers more, so ensure you complete a comprehensive warm-up and include some fast strides before commencing the session.
Remember that when running intervals at higher intensities, you’ll be putting your body under a lot of stress, so don’t forget always to do a thorough warm-up that includes some fast strides before starting any interval sessions.
The key is to run at an appropriate pace so you can recover and still complete the rest of your weekly training sessions without excessive fatigue.
A final recommendation is to focus on your own pace and avoid turning these interval sessions into races. This is common in group training settings, so it is essential to stick to your desired effort.
And with that, here are a few classic interval sessions for you to try out.
Interval Workouts For Runners
Before jumping into any interval session, be sure to start with a solid warm-up. This helps activate your muscles, prep your cardiovascular system, and reduce injury risk.
Aim for 15-20 minutes of easy jogging, followed by dynamic drills like leg swings, skips, or high knees.
After the workout, always include a cool-down jog and light stretching to help your body recover and add valuable easy mileage to your week.
Here are five classic interval training workouts to try:
#1: 400m Repeats
6–10 x 400m at 5K pace with 1:1 work-to-rest ratio (e.x., 90 seconds on, 90 seconds jog)
#2: 1K Repeats
4–6 x 1,000m at 10K pace with 90–120 sec jog or walk recovery
#3: Pyramid Intervals
200m, 400m, 600m, 800m, 600m, 400m, 200m at 5K pace or faster, with equal jog recoveries in between each.
#4: 30/30s
15–20 rounds of 30 seconds hard / 30 seconds easy
#5: Hill Repeats
6–10 x 30–60 second sprints up a hill with a walk/jog back down
Still looking for an easy-to-follow, effective training plan?
Look no further! Now that you understand interval training, it’s time to create a great training plan to help you achieve your running goals.
Check our full list of free printable training plans:
