Why HIIT Enthusiasts are Choosing Low-Impact Exercise: 5 Key Reasons

If you've peeked at a gym schedule or your ClassPass app lately, you've likely spotted a wide range of high-intensity interval training (HIIT) options. Everything from CrossFit and cardio plyometrics fall under this umbrella, as do sprint workouts like Barry's Bootcamp and interval-infused routines like SoulCycle, CycleBar, and most Peloton classes.

But fitness experts and researchers agree: you need not pound so hard to score major wellness benefits. While HIIT routines and classes are still in high demand, word is slowly getting out about the potential gains you can get from lower-impact options, too.

Read on to learn more about how to work smarter rather than harder—and still rack up major muscle, mental health, and longevity benefits.

High-intensity interval training (HIIT) is an exercise strategy that uses alternating periods of short, intense exercise with less-intense recovery periods, explains Christopher Gagliardi, a San Diego, California-based scientific education content manager for the American Council on Exercise (ACE). These workouts can involve cardiovascular, muscular training, or both.

The push periods are 'designed to get your heart rate up high for short bursts that really push you to your max,' adds Katie Dunlop, a Laguna Beach, California-based certified personal trainer, sports nutrition specialist, and the founder of Love Sweat Fitness and the MOVE app. Within 30 seconds or so during the 'on' intervals, HIIT-ers should be nearly out of breath and at about 80 to 90 percent of maximum effort, adds Dunlop. Jump roping, box jumps, sprints, and burpees are all examples of traditional HIIT MVPs.

Between each pedal-to-the-medal segment, HIIT workouts sprinkle in brief recovery periods of less intense movements to create an interval circuit-style routine, says Carissa Fernandez, a Denver, Colorado-based Club Pilates master trainer.

'When you know that rest is coming up, you can go all out—which can be more encouraging than a traditional low-and-slow workout,' adds ShaNay Norvell, a NSPA-certified personal trainer at Fuel Fitness Studio in Atlanta, Georgia.

If your schedule is overflowing, HIIT can be a boon, Gagliardi adds: 'HIIT offers equal and better results in less time when compared to many other training programs. In other words, you can get the same benefits as you would from traditional exercise programs, just in a shorter amount of time. This addresses the perceived lack of time that many people state as being the reason for not exercising regularly.'

There are also several other proven benefits of HIIT:

Other documented health benefits include:

Low-impact training involves any physical activity that puts minimal stress and force on your joints, says Michelle Parolini, NASM-CPT, a Pittsburgh, Pennsylvania-based manager of coach development for Row House.

'Sprinting on a treadmill, burpees, and jumping jacks are all high-impact training that adds stress to the joints,' Parolini says. 'Low-impact exercises can add longevity to your fitness regimen because they are gentler on the body and typically involve keeping at least one foot on the ground at all times.' (Seated activities are also low-impact.)

Gagliardi says that sometimes people confuse low-impact with moderate-intensity continuous training (MICT) or low-intensity steady state (LISS) training, which involves continuous exercise at a moderate or low and sustainable intensity. But it's worth noting that 'low impact' does not necessarily mean 'low intensity,' and not all HIIT workouts are high-impact. Parolini's beloved rowing, for instance, is an excellent example of a mode of exercise that can be low impact and high intensity. Cycling can be similar. Both allow you to push hard and accomplish HIIT-style training without impacting your joints.

It's important to make the distinction between low-impact activities and lower-intensity activities when compared to HIIT.

'Low-impact is gentle on the joints, but does not always indicate the intensity of the exercise from the perspective of how hard your heart is working,' he clarifies. 'Walking is considered a low-impact exercise, but it can be performed at various intensities based on your speed and incline. High-intensity walking can also improve fitness. Low-impact exercise can lead to the same health and fitness benefits as HIIT, but the workout will be longer and the benefits may take longer to achieve.'

Same results with less stress? Sounds pretty tempting.

As we mentioned, an easy way to remember what low-impact workouts include is anything seated or that can be performed with one foot on the floor at all times.

'Without plyometrics or jumping, low-impact workouts involve less pounding on the joints and are safer for those who may have knee, ankle, or joint issues,' says Norvell.

Considering the fact that about 1 in 10 Americans currently have osteoarthritis or degeneration of joint cartilage between bones, low-impact workouts can offer some serious relief. (This is just one example of many conditions that can be exacerbated by high-impact exercise.)

'Low-impact workouts are less likely to cause overuse injuries or burnout,' says Parolini. Parolini used to swear by boot camp-style training; complete with 'endless box jumps, treadmill sprints, and burpees. My neck and knees always bothered me, and I thought that was par for the course.'

That is until she was introduced to the rowing machine. Parolini shifted her HIIT workouts to a low-impact environment, and this pivot has allowed her to 'keep the intensity level up while decreasing pain, mitigating injury, improving overall body strength, increasing range of motion and core engagement, and giving me overall better health.'

Especially if you do HIIT workouts out of feelings of obligation rather than joy, Fernandez says that these high-intensity and high-impact routines can spike levels of the stress hormone cortisol. Beyond adding to your current stress levels, over time, high cortisol can impact everything from mental health to heart disease risk to muscle and bone strength, the Cleveland Clinic confirms.

And if a sweat sesh doesn't spark joy, it's going to be something you want to escape from rather than tune into. The mind-muscle connection is vital to help you get the most from your workouts physically. At the same time, the mind-body connection is one of the key reasons why exercise plays a crucial role in our mental health. If your mind is somewhere else besides your movements, you'll be at increased risk for injury and won't be able to get as much out of every minute.

Low-impact workouts like yoga or Tai Chi focus on connecting each motion with mindfulness in a way that aligns all of the above—and often helps to lower overall stress levels rather than elevate them.

We can't be the only ones who have woken up the morning after a tough Tabata plyometrics workout or a CrossFit WOD like Mary only to find that our muscles are begging for mercy—and an unplanned day off.

Low-impact exercises are ideal for many individuals because between-session recovery may be shorter. 'By incorporating low-impact exercises into your routine, you can maintain consistent activity without placing excessive stress on your body, so you can stay active without as many setbacks,' explains Parolini.

Plus, athletes recovering from injuries who still want high-intensity strength and cardio can opt for a low-impact version of a HIIT workout. (Find more on this below in 'How to Make the Switch').

Before losing 45 pounds and becoming a certified personal trainer, Dunlop admits that she tried 'every training style—most of which were HIIT or gym-based. I would go hard for a couple of weeks and get burnt out or be too sore to do anything for a few days and wasn't able to create a sustainable fitness routine.'

When Dunlop started sprinkling in low-impact training days to her agenda, she felt 'much more balanced mentally and physically. My cortisol levels dropped and I felt improvements in my overall body composition. I also was able to stay consistent because I wasn't working at 100 percent all the time. Not to mention those training days gave me more time to work out with friends going for hikes or beach walks.'

From beginners to older adults to those with mobility limitations, low-impact workouts offer a diverse array of options.

'Low-impact workouts are accessible to people of all fitness levels because they offer a gradual and manageable approach. As fitness levels grow, low-impact work is adaptable by intensity, duration, and range of motion to match current abilities,' says Parolini.

Imagine starting with a slow and steady walk on the treadmill. After three months of consistent training, perhaps you're ready to add some incline. Then three months later, you might be ready to pepper in some higher-speed intervals (say, +1 MPH for 30 seconds every 10 minutes).

Norvell, for one, found herself gravitating from HIIT training sessions to prepare for half-marathons to lower-impact alternatives now that she's in her 40s. 'My knees feel better, and I'm still able to do more intense training and gain benefits in terms of cardiovascular endurance and strength benefits, just without as much impact,' says Norvell.

Everyone can benefit from exercise, says Gagliardi, but those benefits only accrue if it's something you can stick with. Even if you swear by HIIT some of the time, your body might appreciate some lower-impact sessions in the mix.

Whether this is a walk or mobility flow as part of your active rest or a high-intensity, low-impact bodyweight or dumbbell strength routine, this is a savvy strategy to strike a balance between intense workouts and adequate recovery periods. (ICYMI, here are three legit reasons why active recovery is so important, plus exactly how to incorporate some into your training schedule.)

'Finding the right amount and intensity of exercise needed to lead to the greatest adherence is crucial,' says Gagliardi.

Whether you do HIIT or MICT, you'll score the same benefits, says Gagliardi—it just will take a different amount of time to achieve the same results.

To put this into perspective, think about a hypothetical trip to Alaska (if you live in the contiguous 48 states). You could fly there from your nearest airport, or jet to Seattle to cruise your way up and take in the scenery along the way. If you're really feeling ambitious and love a road trip, you can fuel up and drive. There's no universal 'right' answer; it varies based on your goals.

'You have the same goal of getting to a destination, but have different options for getting there,' says Gagliardi, and the same holds true for fitness styles.

To help the ideal mix of fitness methods, including intensity and impact levels, Gagliardi often asks clients:

For some individuals, HIIT is the solution and works well for all training sessions. For others, MICT is the best option, advises Gagliardi. A combo of HIIT and MICT may be the best option, perhaps with some LIIS sprinkled in.

'Another option is reduced-exertion high-intensity interval training (REHIIT) which is an evolution of HIIT that shortens the duration and creates a workout that does not feel quite so tough,' says Gagliardi.

This would allow your HIIT routine to be a bit less taxing, and possibly, a bit more community-boosting since you'll actually be able to catch your breath enough to maintain somewhat of a conversation.

For most people, a blend is best to deliver results and to create a fitness plan that's possible to stick with, says Dunlop.

'Too much HIIT and you might get burnt out or overworking your body leading to injuries. Too much low-impact may just get boring, or you may not see the physical changes you're looking for as far as body composition goes,' continues Dunlop. 'I personally always incorporate at least two days of low-intensity workouts into my week to allow my body to recover from some of my more intense workouts.'

Here's what this might look like in practice:

From reduced risk for heart disease and type 2 diabetes to impressive calorie burn, HIIT workout benefits abound. Plus they're very time-efficient if your schedule is jam-packed. That said, you can score all of those benefits from lower-impact options if you invest a bit more time.

For some fitness fiends, it might feel like the only way to reach your goals is to push at 100 percent each and every session. 'That couldn't be further from the truth. Low-impact, HIIT workouts offer an environment for continued growth and complete fitness,' says Parolini.

Lower-impact workouts are scalable, sustainable, and a stellar option for those seeking to prevent or recover from injury. They're also excellent for building community (since you may actually sometimes have the capacity to chat!) and might be more enjoyable for some populations. 'Everyone can benefit from incorporating lower-impact movement into their training,' confirms Parolini.

The growing interest in lower-impact options among HIIT lovers signifies that we're thinking long-term. Rather than stressing over our maximum calorie burn in a minimum of minutes, incorporating some low-impact elements into your training schedule can support joint health, long-term physical activity sustainability, diverse fitness goals, stress relief, and inclusivity. Whether they're in tandem with or in place of the HIIT programs, fit folks who used to swear by HIIT can benefit from incorporating lower-impact exercises into a fitness routine.