High-intensity interval training, better known as HIIT, has become one of the most talked-about ways to stay fit, and it’s not hard to see why. It packs a lot of results into a short amount of time, which makes it a natural fit for anyone with a packed schedule, including some of the busiest people in the world.
Let’s take a look at eight celebrities who have leaned into this style of training and what their routines actually look like.
1. Jessica Biel and the Norwegian 4×4 Method
Jessica Biel has helped bring a specific style of interval training into the spotlight, one that alternates four minutes of intense cardio with three minutes of light movement. Research backs this approach, showing that this kind of interval workout can improve fitness faster than steady-pace exercise like jogging or cycling. This is exactly the kind of improvement that shows up when you track your own numbers.
If you’ve ever used an online vo2 max calculator to check how efficiently your body uses oxygen during exercise, you’ll notice that consistent interval training tends to push that number upward over time. So while Biel’s routine looks simple on paper, the science behind it explains why it works so well.
2. Jennifer Garner Mixes Boxing With Cardio Bursts
Jennifer Garner has spoken openly about training hard to get into shape for physically demanding film roles. Her preparation reportedly included boxing, high-intensity interval training, and Peloton rides, guided by a longtime trainer who noted she handled the intense work well.
This kind of mixed approach naturally raises your calorie needs, which connects to another useful number worth knowing. Anyone curious about how to estimate basal metabolic rate will find that higher activity levels, like the ones Garner’s routine demands, shift that number upward, since your body needs more fuel just to keep up with the extra effort.
3. Chris Pratt’s High-Effort Transformation Routine
Chris Pratt has taken on some of the most demanding physical transformations in Hollywood. His training included P90X, running, swimming, boxing, and kickboxing, paired with a significantly increased calorie intake to support the intensity of his workouts. What stands out here is how closely his diet and training worked together. Since intense workouts burn through energy quickly, Pratt’s team made sure his food intake matched the demand, which is a good reminder that HIIT works best when it’s paired with proper fueling.
4. David Beckham’s Treadmill-Based HIIT
David Beckham built much of his athletic shape through disciplined training, and part of that included high-intensity work on the treadmill. Short, fast bursts followed by brief recovery periods helped him stay lean while also supporting the kind of endurance his active lifestyle demands. It’s a simple setup that doesn’t require fancy equipment, just a treadmill and the willingness to push hard for short stretches.
5. Britney Spears and High-Energy Spin Classes
Britney Spears has used spin-based HIIT to stay in shape, combining short bursts of full-speed cycling at high resistance with brief recovery periods in between. This style of training is popular because it delivers a strong cardio workout in a shorter window than traditional steady-state cycling, making it easier to fit into a busy day.
6. Scarlett Johansson’s Blockbuster-Ready Training
Scarlett Johansson has relied on HIIT to prepare for physically intense film roles. Combining cardio and resistance work in short, powerful bursts, this training style has remained a consistent favorite for getting in superhero-ready shape. It’s a practical choice for anyone juggling a tight schedule, since the format delivers strength and cardio benefits without requiring hours in the gym.
7. Hugh Jackman Pairs Heavy Lifting With HIIT
Hugh Jackman is known for maintaining a muscular, lean physique well into his fifties, and interval training plays a real part in that. Studies suggest that combining heavy lifting with HIIT is one of the most effective ways to build muscle while staying lean, and Jackman’s routine reflects that balance closely. His approach shows that HIIT doesn’t have to replace strength training, it can work alongside it.
8. Zendaya’s Fun, Fast-Paced Circuits
Zendaya has been open about not loving traditional gym workouts, so she leans on full-body HIIT circuits led by her personal trainer, mixing them with activities like hiking and tennis to keep things enjoyable. Her approach proves that HIIT doesn’t need to feel like a punishment. It can be built around movement you genuinely look forward to.
The Bigger Picture
What ties all eight of these routines together is the same basic idea: short bursts of intense effort, followed by rest, repeated enough times to genuinely challenge your body. Whether it’s Biel’s structured intervals or Zendaya’s playful circuits, the format flexes to fit different personalities and schedules. And that flexibility might be exactly why HIIT continues to be a favorite among people with very little time to spare, celebrities included.