Interval training’s stock has soared in recent years. Is it any wonder, when it promises to deliver impressive health and fitness perks in a shorter time frame than other workouts? Sessions can be fun, varied and, best of all, finished within half-an-hour – but is it suitable for everyone?
We consulted a collection of experts, and they fell in favour of interval training for all (or, at least, the vast majority of people). However, not everyone’s workout will look the same. While experienced exercisers may favour a sweat-soaked HIIT session, those newer to exercise will be better-served by a more accessible form of interval training. Research has shown even walking intervals can offer significant benefits – more on this below.
Read on to find out more about interval training, including its many benefits and how to give it a go, whether you’re an exercise veteran or just looking to add some mood-boosting movement into your week.
What is interval training?
Any workout with structured undulations in intensity can fall under the umbrella term of interval training – in other words, alternating between high-intensity bouts of work and lower-intensity phases which allow you to recover. This could come in the shape of a series of quick sprints with a short recovery walk after each one, or a kettlebell circuit which sees you perform each exercise for 40 seconds, then rest for 20 seconds before starting the next one.
The second example is also known as high intensity interval training or HIIT. This is a workout style favoured by the likes of David Beckham, Beyonce and Scarlet Johansson, to name a few. But it’s not the only type of interval training out there, and there are other options to suit all fitness levels and abilities.
“Interval training offers a lot of great benefits for both experienced athletes and the average person, making it a fantastic way to approach a workout routine,” says Alasdair Nicoll, a personal trainer and tutor at The Fitness Group. “One of the biggest perks is how efficient it is. You can get the same, if not better, results from shorter bursts of high-intensity exercise mixed with rest periods, compared to longer, steady workouts. This is perfect if you’re busy and need to squeeze in a quick, effective workout.”
With interval training, you can tailor your intervals to your fitness level and wellbeing goals, working up from shorter periods of activity with easier exercises and lighter weights to longer intervals with harder exercises and heavier weights. It really depends on what you’re trying to achieve, but the beauty of this style of exercise is that it can be modified so anyone can try it. Your couch to 5K app? That’s essentially a form of interval training.
International fitness training and support manager at Orangetheory Fitness Sean Johnson explains that “while it’s common in the gym, interval training can also be practised with running, cycling or swimming. It’s suitable for all genders, offering tailored intensity based on your fitness levels. But it can be especially beneficial for women in midlife because of its effectiveness in maintaining cardiovascular health and muscle mass. For those with specific goals, it’s often recommended for weight loss because it increases metabolism and burns calories effectively. It can also be used to enhance endurance and strength, and it’s great for improving athletic performance and general fitness.”
You don’t need a gym membership to reap these rewards either. You can also try interval training with weights at home, running on a track, in the park, on a treadmill or swimming in your local pool. “This variety helps you avoid hitting a workout plateau (when you don’t see any gains despite working out) and keeps you motivated to stick with it,” says Nicholl.
What are the benefits of interval training?
The benefits of interval training will depend on your training experience and how you decide to do it. For example, picking a cardio-focussed activity like running, swimming or cycling will have the primary perk of improving the performance of your heart and lungs, while a weighted circuit can contribute to improved strength and muscular endurance. However, interval training in all forms can have plenty of wider health benefits.
“Over time, interval training can help lower your blood pressure, improve your cholesterol levels and reduce your resting heart rate, all of which are great for your overall cardiovascular health. You’ll also find that both your aerobic and anaerobic fitness levels improve, making everyday activities easier and less tiring,” says Nicholl.
Interval training works both the aerobic and the anaerobic systems. During a few minutes of high-intensity exercise, the anaerobic system uses the energy stored in your muscles. This exercise leads to lactic acid build-up and causes oxygen debt, which is what makes your muscles feel tired and sore.
Then the heart and lungs work together to make up the oxygen debt and break down the lactic acid. During this process, your aerobic system converts stored carbohydrates into energy, burning calories.
“Interval training is amazing for burning calories both during and after your workout, thanks to something called the afterburn effect,” explains Nicholl. “This means you keep burning calories even after you’ve finished exercising, which is handy for weight loss and improving body composition. Another bonus is that the varied nature of interval training can help reduce the risk of injuries. As it includes a mix of high and low-intensity activities, your muscles and joints get a chance to recover during the lower-intensity periods. This balanced approach helps prevent the overuse injuries that can happen with repetitive, high-impact exercises."
How to do interval training with running
“My advice for beginners would be to start slow and begin with moderate intervals, then gradually increase the intensity,” says Johnson.
“Always warm up and cool down before and after you train in this style. Stretch, do some breathing exercises and get your heart rate up before you dive in. It’s also essential to listen to your body. Don’t overtrain and make sure you take adequate rest. You’ll see better results this way and avoid injuring yourself.”
You can try a simple running exercise to begin with. For example:
Depending on your fitness goals and level you can adjust the duration of your intervals, the speed at which you’re walking, running or jogging and the number of repetitions. You can also use wearables, such as fitness trackers, smart rings and fitness bands to monitor heart rate.
Johnson explains that “if you want to optimise your interval training remember that consistency is key. You should be doing regular sessions to see results. Variation can also help so try mixing different exercises to target various muscle groups. You can also look at other areas of health to support your training, for example, a balanced diet of adequate protein intake for muscle repair and carbohydrates for energy will yield better results with this kind of training. And adequate sleep and stress management are crucial.”
How to do walking intervals
If you don’t feel ready for running intervals, a study published in the Mayo Clinic Proceedings journal found that “high-intensity interval walking may protect against age-associated increases in blood pressure and decreases in thigh muscle strength and peak aerobic capacity”.
The protocol used during this randomised control trial, which focussed on middle-aged and older people, went as follows:
How to do interval training with weights
Below, you can find a simple weighted circuit you could do with just one dumbbell.
Perform each exercise for 40 seconds, resting for 20 seconds after each one before moving on to the next exercise. Repeat this sequence for three total rounds for an 18-minute workout.
To adjust the difficulty of this workout, you can use a lighter or heavier dumbbell. You can also adjust the length of the intervals – for example, working for 30 seconds and resting for 30 seconds.
Looking for tips on starting running? Read our beginners’ guide to running a half marathon, according to experts
