HIIT Workouts Too Intense? Try These 3 Lower-Impact Variations

When it comes to workout efficiency, there's a reason high-intensity interval training (HIIT) maintains its popularity. For example, a July 2021 study in the ‌International Journal of Environmental Research and Public Health‌ reported that the short bursts and brief rests characteristic of HIIT can improve exercise capacity and endurance and boost metabolic health along the way.

But not everyone loves HIIT's usual mix of high-impact, intense moves. And if you've come to dread one of these workout sessions, that means your motivation may be waning, too. Fortunately, you have options. Check out these three alternatives, which bring just as many benefits, but let you work out the way you want.

Short for high-intensity, low-impact exercise, HILIT offers short and intense intervals of work without the bounce.

You'll still get your heart rate up in the same way as you would with a more jump-filled HIIT session as long as you're moving in brief, intense bursts, Cordelia Carter, MD, sports orthopedic surgery specialist and director of the Center for Women's Sports Health at NYU Langone Health in New York.

"Modification and selecting the right exercises is key with HILIT," she says. "You can take just about any move that involves jumping and make it into a low-impact version that can be done at the same pace."

For example, that might mean doing Bulgarian split squats instead of jump squats, or doing burpees without jumping forward and back in the middle. Any move that can be done in intervals— similar to sprints if you're running or biking — can be appropriate for a HILIT workout, says Sabrena Jo, CPT, personal trainer and American Council on Exercise senior director of science and research Here's what she recommends:

• ‌Low-impact cardio exercises:‌ These can include exercises like stationary cycling, rowing or using an elliptical machine to elevate your heart rate without putting excessive stress on your joints.
• ‌Strength training:‌ HILIT workouts often incorporate resistance exercises using body weight, dumbbells or resistance bands to build strength and tone muscles. Examples include squats, lunges, push-ups and planks.
• ‌Plyometric exercises with modifications:‌ Plyometric exercises involve explosive movements such as jumping or bounding. In HILIT, these exercises are modified to reduce the impact. For instance, instead of high jumps, you can do exercises like step-ups, modified burpees or knee lifts.
• ‌Core exercises:‌ HILIT workouts often include core-strengthening exercises like plank variations, Russian twists or mountain climbers to improve stability and overall body strength.

"The specific exercises and intensity levels can vary depending on the program," Jo says. "The main focus of HILIT is to provide a challenging workout without the high-impact stress on the joints associated with traditional HIIT workouts."

Those brief, intense exercise moments may be ideal for some, but if you're just getting started with working out or you just don't like exercising that way, consider REHIT: reduced-exertion, high-intensity interval training.

This type of workout includes longer recovery periods and involves briefer intervals and a shorter workout duration overall. For example, a HIIT workout might have a 30-second rest between intervals, or even a shorter rest time — like a Tabata, which has 10 seconds of rest — but REHIT might have up to 3 minutes of recovery time between exercises.

Because of shorter workout duration, you'll likely be doing fewer exercises as well, in order to focus on just a few that can be done at high intensity. For comparison:

• ‌HIIT:‌ Between four to 10 exercises in a set, 30-second rest intervals between sets, about 20 minutes total workout time.
• ‌REHIT:‌ Between two to three exercises, 20-second high-intensity interval per exercise, 3-minute rest between sets, about 10 minutes total workout time.

Nearly any type of exercise can be made into a REHIT interval, as long as you include a longer recovery afterward, Jo says.

For example, a sample REHIT session with a stationary bike would involve a warm-up, followed by an all-out sprint of 20 seconds and a 3-minute recovery period, then another sprint and recovery period. At that point, you can either do a cooldown or consider the REHIT session as a kickoff to a longer workout.

"With REHIT, you can have a challenging workout without pushing your body to the same extent as traditional HIIT," Jo says. "Truly, that makes it accessible to all."

Even if HIIT is a regular part of your workout rotation, it's important that you include other types of exercise to prevent overtraining injuries, according to Samantha McKinney, CPT, trainer at Life Time. For an effective counterbalance, consider low-intensity, steady-state exercise, or LISS.

HIIT relies on short bursts of intense effort along with brief rest periods, and the workout is usually done in under 20 minutes. LISS is a meant to be done in a continuous timeframe with the same level of effort throughout.

"These can complement each other, because HIIT builds fast-twitch muscle fibers and is important for power and strength," she says. By contrast, LISS — which can involve walking, swimming, cycling, running or any other exercise done at a steady pace — is more about developing endurance.

McKinney says LISS is less stressful on your body and can be maintained for longer periods of time, even several hours.

"Ultimately, I recommend doing both," she adds. "You can't replicate the benefits of LISS with HIIT and vice versa."

Here are some ways you can start incorporating LISS:

• Walk two miles in 30 minutes
• Use a treadmill or exercise bike for 30 to 60 minutes
• Swim at a moderate pace for 30 minutes

The target heart rate for LISS workouts is 50 to 70 percent, which means the key is to keep your heart rate slightly elevated for a longer period of time.

"If someone is just starting out, they can aim for 20 to 30 minutes for a workout," Ronny Garcia, CPT, trainer at Blink Fitness, says. "But the ultimate goal with LISS workouts is to have longer sessions that can last for at least 60 minutes."