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As a certified personal trainer, the question I often get asked is “How much HIIT per week should I do?”

Without knowing anything about a person’s goals or level of stress and training experience, this question is difficult to answer. How much high-intensity interval training you do depends on your fitness level, goals, ability to recover, and more. Here we’ll take the view from 10,000 feet to give you some guidelines on how much HIIT per week you should be doing.

Ready to burn body fat and get that heart rate up? Then let’s go.

What Is HIIT Training?

HIIT is short for high-intensity interval training. This cardio workout is a form of exercise that involves short, intense cardio bouts followed by a lesser intense recovery interval, then repeated for a certain amount of sets. Generally, HIIT intervals last between 20 seconds to 3 minutes with the same amount of recovery or more before doing it again.

Judging your intensity between 1 (easy) to 10 (I’m dying), your HIIT interval should feel between 7 and 9 depending on the length of your interval. For example, holding a high-intensity level for 30 seconds is easier than holding it for 3 minutes. Adjusting your intensity based on the length of the interval always works best.

HIIT vs Steady-State Cardio Training

The two main types of cardio are HIIT and steady-state cardio (SST, also called aerobic training). The main differences between HIIT and SST are time, intensity, and duration. HIIT is short, sweet, and intense, like eight rounds of 20 seconds of burpees followed by 10 seconds of rest (a classic tabata). Alternatively, steady-state cardio is what the name implies: a workout at a longer duration at the same pace, like running a 5K at a 10-minute pace.

HIIT session lasts anywhere from 4 to 30 minutes, while steady-state training should last between 20 to 60 minutes.

There’s an idea floating around the health and fitness space that HIIT is better for fat loss than SST, but in reality, both are good for fat loss, according to recent studies. Choosing which one to do is a matter of time and preference. HIIT has significant benefits if you’re tight on time. Also, HIIT workouts often incorporate a strength element, which steady-state cardio cannot do.

How Often Should You Do HIIT?

Here’s the big money question: How many times per week should you do HIIT? It depends on a lot of things like how much time you have to train, your level of training experience, and your health and fitness goals.

Given you can burn a serious amount of fat in a short time, you may be tempted to do HIIT every cardio session. However, doing so will affect your recovery between cardio and weight lifting sessions.

When performing HIIT, your body releases stress hormones like cortisol. A little amount of cortisol can improve your strength and immunity against the common cold. But elevating your cortisol levels constantly will hurt the body like increased fatigue, mood swings, and muscle weakness. In other words, too much HIIT may destroy your gains.

People often think a little is good then more must be better. When you start to see results and health benefits from your HIIT training, you may think adding more will lead to even better results. But you have to be careful here because you can get too much of a good thing.

In other words, too much HIIT may destroy your gains.

The Swedish School of Sport and Health Sciences conducted a study where they put 11 healthy volunteers through regular HIIT sessions in which they gradually increased the amount of time they spent doing each HIIT session. When they started with only moderate amounts of HIIT, all 11 subjects improved their performance and produced more mitochondria, which is the powerhouse of your cell structure.

But when the frequency was increased without rest between sessions, their mitochondrial function started to deteriorate, the tell-tale signs of overtraining kicked in, and performance dropped. It’s only one study, but you don’t need a study to tell that too much of a good thing is a bad thing.

So, where is the sweet spot?

If you’re a beginner, it is best to ease into it with only one to two HIIT sessions per week, lasting between 10 to 30 minutes. Do this for four to six weeks before progressing. When your fitness level has improved or you are an advanced trainee, anywhere from two to four sessions of HIIT of between 10 to 30 minutes works well.

Doing back-to-back HIIT workouts is not advisable because it may raise your stress levels too high, and all your gains might disappear. Instead, training at a lower intensity between two HIIT sessions will allow your body to recover better, so you can reap the fat loss benefits of HIIT.

Just a short note on recovery and stress: If you’re highly stressed due to work or home life, or some other factor, then, adding to this with extra HIIT sessions is not your best bet. It’s better to stick with the steady-state cardio and its stress-reducing benefits.

Signs of Overtraining

Trainees mistakenly think all the gains happen in the gym and not in the rest and recovery. Training hard with HIIT and strength training causes microscopic tears in your muscles. Resting, getting enough sleep, foam rolling, and eating enough protein these tears will heal, and you will get stronger. If you don’t do any of those things, then you’re a candidate for overtraining.

Here are some tell-tale signs that you are overtraining and it’s time for a rest:

You’re always tired after your HIIT session.
You suffer from excessive delayed onset muscle soreness (DOMS), and you are sore for days.
You experience mood swings.
You aren’t sleeping enough.
You lack the enthusiasm to train.
You keep having nagging injuries.
You’re dehydrated.
You experience excessive weight loss.

If you are suffering from two or more of these symptoms, it is time to dial it back and incorporate some recovery pronto.

How to Incorporate HIIT Into a Workout Routine

Here at GGR, we don’t like to leave you hanging. Let’s put the advice into action to develop a sample weekly routine to satisfy the American Heart Association’s cardiovascular exercise guidelines of 150 minutes of moderate-intensity activity per week, and 75 minutes of intense exercise per week.

Here is an example of combining HIIT with weight training:

Monday: Full-body resistance training

Mix upper- and lower-body exercises work on all major muscle groups. Add a low-intensity walk on this day if you choose.

Tuesday: HIIT

Do any battle rope variation for 30 seconds and then immediately get into the side plank and hold it for 30 seconds. Go back to the battle ropes for another 30-second interval and do the side plank on the opposite side. Repeat this sequence for 10-20 minutes, resting when needed.

Wednesday: Rest day

Truly rest today. Your body needs time to recover.

Thursday: Full-body resistance training

Again, hitting all major muscle groups here with new exercises. Adding in a short walk is also okay to do on this day.

Friday: HIIT

Do 20 reps of kettlebell swings and the slams, decreasing by two each time you do a round until you reach two reps for each exercise (such as 20-18-16-14….2).

Saturday: Low-Intensity workout

Perform 30 to 60 minutes of low-intensity activity like walking, jogging, or rowing, in steady-state cardio.

Sunday: Rest day

If you want to move, do no more than 30 to 60 minutes of low-intensity activity like walking

Final Thoughts on HIIT Training Frequency

HIIT is great because who doesn’t want to burn more fat in less time? It is easy to fall in love with the results you glean from doing HIIT, and you may be tempted to add more sessions. But adding will likely exceed your capacity to recover, leading to overtraining. A little HIIT is great, but a lot is not.

Depending on your training experience and fitness goals, keeping HIIT sessions around two to four per week at around 60-90 minutes per session is a sweet spot for a lot of people. Mixing your HIIT training with lower intensity training will allow you to recover better and keep improving without your gains grinding to a halt due to overtraining.

FAQs About HIIT Training

Is a 20-minute HIIT workout a day enough?

When you’re new to combining HIIT and strength training, then yes, 20 minutes of HIIT a day is enough, as long as you don’t exceed four HIIT sessions a week. If you’re an advanced trainee with strength training goals then no, probably not. Combining your HIIT and strength training intelligently works best.

Is it OK to do HIIT every day?

When you’re performing HIIT correctly, you are putting significant stress on your body. And too much stress is a bad thing as discussed above. So, no, it is NOT okay to do HIIT every day.

Is HIIT three times a week too much?

If you’re an experienced trainee with adequate recovery, then three times a week is okay, but keep a lookout for signs of overtraining. If you keep your HIIT session to 75-90 minutes per week total, and you should be okay.

Is one day of HIIT enough?

Yes, it is better than zero, but two or more is preferable depending on your level of experience.

VO2 Max Calculator

We created our own VO2 max calculator so you can estimate your cardiovascular fitness level.

Instructions for this VO2max Calculator

What you need: A walking location, stopwatch

Age

Weight

Walk Time

10 SECOND PULSE COUNT AT TEST COMPLETION

Shane McLean, CPT

Shane McLean is a certified personal trainer who’s worked with a wide variety of clients, from the general population all the way to ex-Navy Seals and college athletes. When he isn't training in his garage gym, he's drinking copious amounts of coffee while spreading the good word about health and fitness.

How Much HIIT Per Week Should You Do? Get Expert Advice