Interval training is one of the most effective and flexible ways to get fit, and it’s been a secret weapon of athletes for the best part of a century. The basic idea is simple: instead of exercising at one steady pace, you alternate between periods of harder effort and periods of easier recovery. That simple structure delivers a remarkable range of benefits in less time than traditional cardio.
Best of all, interval training isn’t a single rigid workout. It’s a broad, adaptable approach that scales to absolutely any fitness level, from a beginner’s gentle walk-jog intervals to an elite athlete’s brutal sprint sessions. Here’s a complete look at what interval training is, its many benefits, and how to make it work for you.
This article is informational and not a substitute for individual medical advice.
What Is Interval Training?
Interval training is any form of exercise that alternates between bouts of higher-intensity effort and periods of lower-intensity recovery or rest. You push a little harder, then ease off to recover, then push again, repeating that cycle for the duration of your workout.
The concept has a long history in athletics, with structured interval methods dating back to running coaches in the early twentieth century. Athletes have always known that intervals build fitness and speed faster than steady, monotonous training. The key thing to understand is that “interval training” is a broad umbrella covering a whole spectrum of intensities, not one specific workout.
Interval Training vs HIIT: What’s the Difference?
This is worth clearing up, because the two terms are often used interchangeably when they shouldn’t be. High-intensity interval training (HIIT) is a type of interval training, specifically, the version where the work intervals are performed at near-maximal effort. You can read all about it in our dedicated guide on the benefits of HIIT.
Interval training as a whole is much broader. The work intervals can be gentle, moderate, or all-out, which means interval training can be scaled to any intensity and any fitness level. HIIT is the intense end of the spectrum; interval training is the entire spectrum. That distinction matters, because it means interval training is far more accessible and adaptable than HIIT alone, you get many of the same benefits, at whatever intensity suits you.
The Types of Interval Training
Interval training comes in several forms:
- Fartlek training: a Swedish term meaning “speed play,” this is unstructured interval training where you vary your pace based on feel, for example jogging and then sprinting to a lamppost. It’s relaxed and beginner-friendly.
- Moderate-intensity intervals: alternating comfortable effort with slightly harder pushes. Accessible and sustainable for most people.
- High-intensity interval training (HIIT): short bursts of near-maximal effort with recovery. Intense and time-efficient.
- Sprint interval training (SIT): all-out sprints with long recovery, the most demanding form, used by athletes.
- Tabata: a specific, very intense HIIT protocol of 20 seconds of work and 10 seconds of rest, repeated for four minutes.
This variety is exactly why interval training suits everyone. You simply choose the intensity that fits your fitness and goals.
What Are The Main Benefits Of Interval Training?
1. Adaptable to Any Fitness Level
This is interval training’s greatest strength. Because you control the intensity of your work intervals and the length of your recovery, you can tailor it perfectly to your ability. A beginner might alternate walking and brisk walking, while an advanced athlete performs all-out sprints. The work-rest structure lets you handle harder efforts than you could sustain continuously, easing you into intensity without overwhelming your body. No other cardio approach is quite so scalable.
2. Remarkably Time-Efficient
Interval training delivers impressive fitness gains in a fraction of the time of steady, continuous cardio. Research shows that interval workouts can produce comparable, and sometimes superior, improvements in cardiovascular fitness and body composition in far less time. For busy people, that efficiency is invaluable.
3. Improves Cardiovascular Health
By repeatedly raising and lowering your heart rate, interval training gives your cardiovascular system a powerful workout. It strengthens your heart, helps it pump blood more efficiently, improves the health and flexibility of your blood vessels, and is associated with lower blood pressure over time. Like all good cardio, it’s excellent for long-term heart health.
4. Burns Calories and Aids Fat Loss
Interval training is an efficient calorie burner, and research shows it’s effective for reducing body fat, including stubborn visceral fat around the organs. The intensity also produces a modest afterburn effect, where your body continues burning slightly more calories after the session. It’s worth keeping that afterburn in perspective, it’s real but small, and fat loss still ultimately depends on overall energy balance, the principle we explain in our bulking vs cutting guide.
5. Boosts Both Aerobic and Anaerobic Fitness
By combining harder efforts with recovery, interval training develops both of your energy systems at once, your aerobic (endurance) capacity and your anaerobic (short, powerful effort) capacity. That dual improvement enhances your overall fitness and athletic ability across the board.
6. Improves Metabolic Health
Interval training has impressive effects on metabolic health. Studies show it improves insulin sensitivity and helps regulate blood sugar, making it a valuable tool for managing and reducing the risk of type 2 diabetes, as well as improving cholesterol and other markers of health.
7. Versatile and Applies to Any Activity
You can apply interval training to almost any form of cardio. Running, cycling, rowing, swimming, or bodyweight circuits can all be turned into interval workouts simply by varying the intensity. This versatility keeps training fresh and lets you use whatever equipment or activity you enjoy or have access to.
8. More Engaging Than Steady-State Cardio
Let’s be honest: long, steady cardio can be monotonous. The changing pace of interval training keeps your mind engaged and the time passing quickly, which many people find makes workouts more enjoyable and easier to stick with. Better adherence means better long-term results.
9. Enhances Athletic Performance and Recovery
There’s a reason athletes have relied on intervals for generations. Interval training improves speed, power, endurance, and the ability to recover quickly between bursts of effort, exactly the qualities that matter in sport. Training your body to recover fast during the rest intervals carries directly over to athletic performance, including explosive efforts like sprinting.
What Is Interval Training?
Hold your horses, we’ll get to the benefits in just a few moments but first, we need to take a look at precisely what interval training is.
Interval training is a training protocol in which the participant/participants alternate between periods of HIIT exercise and low-intensity exercise for pre-determined amounts of time.
If you want a very basic example of interval training, imagine walking for 30 seconds, sprinting for 30 seconds, and then repeating this cycle over and over again for as many rounds as you can fit into, say, 20-minutes.
How to Structure an Interval Workout
Building an interval session is straightforward once you understand the variables:
- Warm up first. Always start with 5 to 10 minutes of easy movement to prepare your body and reduce injury risk.
- Set your work-to-rest ratio. Beginners should use longer recovery periods relative to work (for example, 1 minute of effort to 2 minutes of recovery), while fitter individuals can shorten the rest.
- Choose your intensity. Match the effort of your work intervals to your fitness level, from moderate to all-out.
- Pick your duration. Interval sessions are typically short, often 15 to 30 minutes including warm-up and cool-down.
- Cool down. Finish with a few minutes of easy movement to bring your heart rate down gradually.
Sample Interval Workouts
Beginner (walk-jog): After warming up, alternate 1 minute of jogging with 2 minutes of walking, repeated 6 to 8 times.
Intermediate (moderate intervals): Alternate 1 minute of hard effort with 1 minute of easy recovery on a bike, rower, or running, for 15 to 20 minutes.
Advanced (sprint intervals): After a thorough warm-up, perform 30 seconds of all-out sprinting followed by 90 seconds of walking, repeated 6 to 10 times.
Start where you are and progress gradually as your fitness improves.
Interval Training vs Steady-State Cardio
Both have value. Steady-state cardio, exercising at one consistent moderate pace, is easy to recover from, sustainable in high volumes, and gentle on the body. Interval training is more time-efficient, tends to improve fitness faster, and keeps things more engaging, though the harder versions demand more recovery. Rather than choosing one, many people get the best results by combining both: interval sessions for efficiency and fitness gains, plus some steady cardio for easy volume and active recovery.
Who Should Do Interval Training?
The beauty of interval training is that it suits almost everyone, precisely because you can dial the intensity to your level. Beginners can start with gentle walk-jog intervals, busy people can get an effective workout in minimal time, and athletes can push with demanding sprint sessions. As with any exercise, if you have a heart condition or health concern, it’s wise to check with a healthcare professional first, especially before attempting higher-intensity intervals.
Frequently Asked Questions
What is the difference between interval training and HIIT? HIIT is a specific type of interval training performed at near-maximal intensity. Interval training is the broader category, covering all intensities from gentle to all-out. All HIIT is interval training, but not all interval training is HIIT.
Is interval training good for beginners? Yes, it’s excellent for beginners, because you can set the intensity and recovery to match your fitness. Starting with simple walk-jog intervals is a great, accessible way to build fitness.
How often should I do interval training? It depends on the intensity. Moderate interval sessions can be done several times a week, while very high-intensity sessions need more recovery, typically two to three times a week. Always allow adequate rest between hard efforts.
Is interval training better than steady cardio? It’s more time-efficient and can improve fitness faster, but both are valuable. Steady cardio is easier to sustain in high volumes, so the best approach for many people is a combination of the two.
Can interval training help with weight loss? Yes, it burns calories efficiently and effectively reduces body fat, especially when combined with a calorie-controlled diet. As with any exercise, results depend on your overall energy balance.
The Bottom Line
Interval training is one of the most effective, efficient, and adaptable ways to exercise. By simply alternating harder efforts with recovery, you can improve your cardiovascular fitness, burn fat, boost your metabolic health, and enhance your athletic performance, all in less time than traditional cardio and at whatever intensity suits you.
That adaptability is the real magic. Whether you’re taking your first steps into fitness with walk-jog intervals or you’re an athlete chasing sprint times, interval training scales to meet you where you are. Start at your level, progress gradually, and enjoy one of the most rewarding and time-efficient training methods there is.
