You Shouldn't Exceed This Number Of HIIT Workouts Per Week

Because HIIT workouts are so short and sweet, it might seem like you can do them every day as a way to up your fitness game and reach all your goals in record time — without necessarily overdoing it. But trainers says there’s a sweet spot when it comes to the number of times you add a sweaty HIIT session into your week.

HIIT, or high intensity interval training, is all about exercising as hard as possible for short periods of time, says Emily Skye, a fitness trainer and creator of the workout platform Emily Skye FIT. “During a HIIT workout, you alternate bursts of high-intensity exercise — the work phase — with shorter periods of rest or recovery — the rest phase,” she tells Bustle. “For example, you may give it your all for 40 seconds of star jumps, then rest for 20 seconds.” You’d then repeat your heart-pounding work/rest cycle for a few rounds, typically for a grand total of about 15 minutes.

Interval training works perfectly with pretty much any type of cardio exercise, whether you’re doing rounds of mountain climbers, pedaling on a bike, or running down the street. The on-off nature of HIIT has been shown to improve aerobic or cardio fitness, Skye says. It’s also a great complement to other workouts, like strength training, that you might do in a week. “Regular cardio increases oxygen supply to your muscles, allowing them to work harder,” Skye says.

As a bonus, a HIIT sesh will fill you with good hormones, perk up your mood, and get your blood flowing for extra glowy skin, she adds. If you’re looking for a fun, fast, and effective workout with tons of benefits, HIIT is it. But according to fitness pros, it’s possible to do too much of a good thing.

Can You Do HIIT Every Day?

The short answer is no. “Daily HIIT workouts are not recommended,” says Jayda Kapeller, a certified personal trainer and owner of JaydaAFitness. “If [you] choose to do HIIT workouts every day, your body will be under a significant amount of stress and will likely be unable to properly recover, which can lead to extreme soreness and hormone imbalances,” she tells Bustle.

That’s because daily HIIT prevents proper muscle recovery, Kapeller says, since your body quite literally doesn’t get a break. Daily HIIT can also spike your cortisol levels due the constant high-stress — like jumping, pedaling, running, etc. — on the body.

“HIIT also has a higher rate of injury compared to other forms of training,” Kapeller says, because you’re moving so quickly and expending so much energy. Perfect form is essential to making the most of your workouts, and that can get difficult when you’re too tired from the previous day. (Cue twisted ankles, pulled hamstrings, etc.)

Again, even though HIIT only lasts 15 or 20 minutes, and it can be tempting to tack a quick sesh onto the end of a workout, you shouldn’t attempt it every day.

How Often Should You Do HIIT?

How often you click interval workouts on YouTube or add highs and lows to your running routine will depend on your fitness level and goals, but in general it’s best to do HIIT one to two days a week. If you tend to train hard, go for three HIIT workouts, tops.

“[That’s] a good amount of HIIT because it allows for the body to rest and recover,” Kapeller says. After each HIIT workout, she recommends stretching and active rest, all in the name of giving your muscles what they need to repair. Take lots of breaks when interval training, and you should show up to your next workout with plenty of energy, good form, and a reduced risk of injury.

Studies referenced:

Atakan, MM. (2021). Evidence-Based Effects of High-Intensity Interval Training on Exercise Capacity and Health: A Review with Historical Perspective. Int J Environ Res Public Health. doi: 10.3390/ijerph18137201.

Ito, S. (2019). High-intensity interval training for health benefits and care of cardiac diseases - The key to an efficient exercise protocol. World J Cardiol. doi: 10.4330/wjc.v11.i7.171.

Jahrami, H. (2022). Eight-week high-intensity interval training is associated with improved sleep quality and cardiorespiratory fitness in patients with depressive disorders. Sleep Breath. doi: 10.1007/s11325-021-02388-y.

Martland, R. (2020). Can high-intensity interval training improve physical and mental health outcomes? A meta-review of 33 systematic reviews across the lifespan. J Sports Sci. doi: 10.1080/02640414.2019.1706829.

Sources:

Emily Skye, fitness trainer, creator of the workout platform Emily Skye FIT

Jayda Kapeller, certified personal trainer, owner of JaydaAFitness