What Is Sprint Interval Training, and Does It Really Work?

Hot-girl walks. 12-3-20 treadmill workouts. Mat Pilates sessions. The anxiety-inducing pandemic years have been an era of soft workouts, helping people move their bodies without necessarily breaking a sweat or experiencing any level of mental discomfort. But now, as folks return to a somewhat-less-stressful period of life, there seems to be a resurgence of workouts that pose a greater physical challenge.

Exhibit A: sprint training is having a moment on TikTok. Videos with the hashtag #SprintTraining have a combined 89 million views, and creators are posting their personal sprint interval workouts and experiences training like an athlete. They’re going so far as calling sprints a workout “cheat code”, promising results that include transforming your glutes and improving heart health. Even Chris Hemsworth is on board, swapping his heavy weightlifting for more functional workouts and, yes, sprints.

But what does sprint training involve, anyway? And can it possibly provide all the benefits that TikTok claims? Here, a certified run coach breaks down the workout style, its perks, and how to try it yourself.

What Is Sprint Interval Training?

Put simply, sprint interval training is a type of running workout that involves alternating between high-intensity sprints and periods of active recovery (think: walking or easy jogging), says Mireille Siné, MPH, a USATF Level 1 running coach and the founder of Coached by Mireille.

Your sprints and recovery intervals could be a specific distance (e.g., 200 meters, 0.1 miles) or amount of time (say, one minute), she explains. And the work-to-recovery ratio all depends on your fitness levels: beginners are typically best off with shorter sprints and longer rest periods, and as they progress, they can begin to increase the sprint distance or time and decrease the recovery, Siné says.

What speed qualifies as a “sprint” is up to the runner. If you’re aware of your 5K pace, for instance, you might opt to run 400 meters at that speed, spend 200 meters recovering, and repeat these intervals five times, she says. Or, you can use your rating of perceived exertion (RPE). For your sprint period, you might aim for an effort level that feels like an eight out of 10, with 10 being extremely hard. “You’re not really minding what the numbers are saying or trying to hit a certain split,” Siné says. “During this interval where you’re supposed to go hard, did you actually feel like you were going hard so that you could get that recovery after?”

Although you can do sprint intervals on the treadmill, you’re better off completing them on the track, Siné says. You need to be able to quickly adjust your speed, but treadmills tend to have lags, leading you to run harder or recover for longer than you’re supposed to, she explains. Plus, you’re able to easily sprint for a specific distance without needing to do some quick math — you can just look at the lines on the track to know when to stop.

What Are the Benefits of Sprint Training?

Whether you’re a running newbie or a pro, sprint interval workouts are worth incorporating into your training routine.

It improves your endurance.

In a small 2020 study, researchers found that sprint interval training three times a week for eight weeks improved V̇O2 max just as well as moderate-intensity continuous runs. ICYDK, V̇O2 max is the maximum amount of oxygen you can use during intense exercise, and it’s considered the best indicator of cardiovascular fitness and aerobic endurance. The more oxygen you can use, the more energy you can produce, and the more work you can do, according to UC Davis Health. In turn, sprint training can help improve your endurance for longer runs, Siné says.

It boosts cardiovascular health.

Along with V̇O2 max, sprint interval training — specifically, four to six 30-second sprints with four minutes of recovery — has been found to improve health parameters such as blood pressure, cardiovascular function, and insulin sensitivity, according to research published in Sports Medicine. Since uncontrolled high blood pressure can lead to heart attack, heart failure, stroke, and other complications, keeping it within the normal range is key, according to the Mayo Clinic.

It’s efficient.

A typical distance run can last anywhere from an hour and a half to two hours — double the amount of time it’ll take you to complete a sprint interval workout, warmup and cooldown included, Siné says. But since you’re working at a higher intensity, you’re able to get the cardiovascular benefits of running without needing to spend two episodes’ worth of “Succession” out on the track or treadmill.

It makes running more mentally stimulating.

By breaking up your runs into exciting bits of high-intensity movement, the activity can feel a lot less monotonous, Siné says. Plus, sprints can give you the chance to compete against yourself. “I personally love the interval portion of my training because it’s a time to really test myself,” she adds. “You don’t want to always go into these sessions expecting to hit everything on the mark because that way you’re not really improving. You should have an element like, ‘This is above where I am right now, but it’s also where I’m aiming to go, so it’s going to feel difficult.’ It’s going to feel hard. But that is what ends up pushing you to actually get the level you’re training for.”

What to Note About Sprint Training

Sprint interval training can make you feel like a powerful track star, but it shouldn’t make up your entire running routine. A well-rounded week of training should include a mix of easy running, higher-intensity work (such as sprint intervals), and a steady long-distance run, Siné says.

Typically, you should keep your sprint workouts to just one to two times per week, with at least a day of easy running in between, she recommends. Any more frequently than that, and you’re bound to experience burnout and an increased risk of injury, Siné says. “You never want to do hard days back-to-back in a training week,” she adds. “That doesn’t give you enough time to recover and it gives you less chance of adapting to the training overall.”

Before your sprint interval workouts, make sure to do a thorough, dynamic warmup so your muscles are primed and ready for the high-intensity work, Siné says. Try drills such as A skips and B skips, karaokes, and quick feet, all of which will help you practice proper running form that can translate into the workout itself, she says. A cooldown is also a must: “You don’t want to go from a high intensity and then just stop completely,” Siné says. “That’s when you’re incorporating an easy jog and for your heart rate to go down while still in motion.”

And if you’re practicing on a track, make sure you use the outer lanes, which are usually a safe spot for slower, newer runners, Siné says.

A Sample Sprint Interval Training Workout

When you’re ready to give sprint interval training a shot, try this sample workout, courtesy of Siné.

Warmup: Easy jog for 20 minutes.

Workout: Sprint 100 meters, then walk or easy jog for 100 meters. For the sprint, aim for a six or seven out of 10 RPE. Repeat six to eight times.

Cooldown: Easy jog for 15 to 20 minutes.

Once you’re comfortable dashing those 100-meter sprints, increase your work and recovery periods to 200 meters each. When that feels like a breeze, try 400 meters for each work and recovery session.