How Long Should A HIIT Workout Be?

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This article shares the current recommendations of sports performance experts regarding the length of high intensity interval training workouts & the maximum amount of time per week HIIT should be performed.

A friend new to fitness training & I were talking about cardio options for him and I told him my fave is high intensity interval training, and explained why that’s the case.

He said he wanted to give it a try, and asked how long his HIIT workouts ought to take.

I wasn’t sure, so I decided to research the answer for him and here’s what I found.

 

So how long should a HIIT workout last?

There is currently no fixed amount of time that is THE ideal high intensity interval workout length, but most recommendations from top fitness trainers currently range from 7-30 minutes per HIIT workout.
It’s worth noting that recent sports science research has determined that overtraining symptoms develop when the total time of HIIT workouts exceeds 40 minutes per week.

 

It’s important to properly create a HIIT routine in order to get the most benefit and to also steer clear of overdoing it.

In these next few sections, I’ll share the main things to consider when you’re building a HIIT workout plan for yourself.

 

Quick programming note before we get going

If you’re older and new to HIIT, consider reading my article dedicated to us in the over-50 crowd, HIIT For Seniors.

And if you’re looking for HIIT workout ideas that are kind to your joints & bones, I’ve got good stuff for you in What’s A Low-Impact HIIT Workout.

 

 

 

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Science resources included

As is my custom here on heydayDo, I will provide links to all of the relevant sports science & medical resources, clinical studies, and nutritional data used in this article.

 

 

Figuring how long your HIIT workout is

One of the great non-fitness benefits of HIIT is that an effective workout takes up a lot less time than you’d need with a slower steady-state cardio workout to achieve the same results.

Still, a well-developed HIIT program needs to be thoughtfully planned.

Here’s a step-by-step approach so you can dial in the HIIT workout length that is appropriate for you, your fitness level, and your current schedule.

 

#1 Make a weekly HIIT schedule

How many days a week are you planning to do HIIT?

All fitness experts I came across while researching this article unanimously agree that you shouldn’t perform HIIT on consecutive days.

Furthermore, personal trainers experienced with HIIT will advise us to limit our HIIT workouts to just 2-3 times per week, as I read here & here.

 

I wholeheartedly agree with them, as I have direct knowledge of what it feels like to go overboard with high-intensity training.

I share my “too much HIIT” experience a little later in the article.

 

The main issue is allowing adequate time for recovery.

If you’re really giving it 100% – which is what you’re supposed to do during the high intensity portions of a HIIT workout then your body will absolutely need a day off in between HIIT workouts.

Or maybe two days off, considering you’re probably doing other types of training that will demand recovery time from you as well.

So now we’re down to a maximum of three days per week.

 


 

#2 How many HIIT minutes per week?

Without a doubt, I believe that the most important thing here is to not overdo your weekly dose of HIIT.

Too much of a good thing isn’t always a good thing.

Remember that research study I mentioned earlier?

They determined that 50 minutes per week is the average breaking point between

A) getting the most out of HIIT’s benefits, and

B) doing yourself real harm by developing overtraining symptoms.

 

It’s definitely worth noting here that the study was run by two of the top HIIT experts in our country, the research-based Les Mills Fitness and the Penn State University Sports Science Department.

 

Les Mills researchers recommended the following guideline in their follow-up document to this HIIT & Overtraining Study:

 

“To get the full benefits of HIIT and prevent overreaching, our recommendation is to maximize your weekly HIIT sessions that are above 90 percent maximum heart rate to 30-40 minutes and balance them with other, less demanding, workouts.”

 

So now we have up to 3 days to do up to 30-40 minutes of HIIT per week.

There’s just one more minor (optional) consideration to factor into your HIIT workout scheduling.

 

Do HIIT on your off days from weightlifting

This is totally optional.

I did not come across any fitness or HIIT experts in my research who said we have to do this.

And this gentle suggestion is only directed towards those of you who regularly strength train.

 

Depending on your level of fitness…

…you may want to consider taking care of your HIIT workouts on days you’re not pumping iron or doing any other type of intensive resistance training.

The main issue is recovery, allowing adequate time for your body to restore itself between workouts.

The secondary issue would be that if you have specific strength training goals, you’d almost certainly lose reps on your lifts if you did your HIIT workout before your weight training.

Depending on your level of fitness of course.

 

FULL DISCLOSURE:

I have to admit to doing cardio HIIT after my weightlifting on a couple of strength training days per week during a 3-month HIIT + low-carb diet experiment I did on myself from April-July 2019. 

I’m pretty sure I developed overtraining symptoms there at the end of the cycle in July.

I was gassed: tired all the time and strength gains had stalled and started to dwindle on a couple of my exercises.

I believe my weekly HIIT total during that time period (35-45 minutes) was too high, and I also think that doing it sometimes 4 times in a week during that time was too much too.

So this is probably why I brought up the HIIT & lifting on separate days suggestion.

 

Your HIIT’s intensity, duration, recovery

Woman doing a HIIT class workout on an exercise bike with moving arms - heydayDo image

The American College of Sports Medicine (ACSM) recommends that you remain mindful of a HIIT workout’s 4 main features:

  • Intensity
  • Duration
  • Recovery
  • Frequency

Frequency

Frequency we’ve already discussed, it’s how often you perform HIIT on a weekly basis.

Avoid trying to do HIIT on consecutive days, it’s just not a healthy decision.

And also be aware that two 15-minute workouts per week (or three 10-minute workouts) is preferable to one 30-minute session.

 

Intensity

It’s called high intensity interval training because you’re expected to push yourself to at least 80-90% of your heart rate max during the high intensity “work” portion of your HIIT sets.

 

This requires an all-out effort, like 100% all-out.

 

This is at the point where it’s too difficult to have a conversation because you’re that out of breath.

Your leg muscles ought to be shouting to you, especially near the end of each work portion.

If you don’t put in the intensity, you won’t reap the benefits that everyone associated with HIIT training talks about.

Your HIIT success needs your effort at the right intensity level.

 

Duration

Related to your intensity level is the length of time you’re able to sustain that high level of intensity that’s necessary to make HIIT work for you.

Unless you’re an elite athlete, it’ll be impossible for you to go longer than a minute at 80-90% of your heart rate max.

Most people will opt for 30 seconds or less for the high-intensity work part of the set, which is totally fine.

In fact, most of the high-end personal trainers that were quoted in the health articles I came across recommended 15-30 seconds as the preferred high-intensity duration.

Some HIIT workouts are performed with as little as 12-15 seconds of all-out effort during the work portion of the set; this is totally fine too.

The key with your duration is choosing a length of time that allows you to exercise at a high intensity level and stay there for the duration of your work portion.

 

Recovery

We talked about needing at least a couple of days to recover properly after a HIIT workout.

The recovery I’m talking about here in this section has to do with the length of time you recover after each high intensity “work” portion of your HIIT sets.

The minimum suggested recovery:work ratio is 2:1.

So if your high intensity portion is 30 seconds long, then you recover with low-intensity for at least a minute.

If your work portion is 15 seconds long, then recover for at least 30 seconds, and so on.

What someone does during that recovery period will vary from person to person, depending primarily on their level of fitness.

As you become advanced in your HIIT training and your fitness level rises accordingly, you can intensify an occasional workout by going with a 1:1 rest to work ratio.

But that’s a special situation for an advanced HIIT athlete.

 

 

Various HIIT workout lengths

It’s great that HIIT has that wide range of suggested workout lengths I mentioned earlier of 7 to 30 minutes per workout.

That’s a lot of leeway.

The wide range will allow you to easily fit HIIT workouts into your daily & weekly routines.

Here are a few HIIT workout samples to consider.

I plugged in the standard low intensity:high intensity ratio of 2:1, but if you need longer low-intensity recovery time, by all means take it.

 

9 minute HIIT workout

3 minutes of high intensity work + 6 minutes of low intensity recovery = 9 minutes total time

Using 30 second high intensity portions

30 seconds work + 60 seconds recovery x 6 sets = 9 minutes

Using 15 second high intensity portions

15 seconds work + 30 seconds recovery x 12 sets = 9 minutes

 

12 minute HIIT workout

4 minutes of high intensity work + 8 minutes of low intensity recovery = 9 minutes total time

Using 30 second high intensity portions

30 seconds work + 60 seconds recovery x 8 sets = 12 minutes

Using 15 second high intensity portions

15 seconds work + 30 seconds recovery x 16 sets = 12 minutes

 

15 minute HIIT workout

5 minutes of high intensity work + 10 minutes of low intensity recovery = 15 minutes total time

Using 30 second high intensity portions

30 seconds work + 60 seconds recovery x 10 sets = 15 minutes

Using 15 second high intensity portions

15 seconds work + 30 seconds recovery x 20 sets = 15 minutes

 

18 minute HIIT workout

6 minutes of high intensity work + 12 minutes of low intensity recovery = 18 minutes total time

Using 30 second high intensity portions

30 seconds work + 60 seconds recovery x 12 sets = 18 minutes

Using 60 second high intensity portions

60 seconds work + 2 minutes recovery x 6 sets = 18 minutes

 

30 minute HIIT workout

10 minutes of high intensity work + 20 minutes of low intensity recovery = 30 minutes total time

Using 30 second high intensity portions

30 seconds work + 60 seconds recovery x 20 sets

Using 60 second high intensity portions

60 seconds work + 2 minutes recovery x 10 sets

 

 

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HIIT related questions

Here are answers to a few of the common questions asked regarding high-intensity interval training workouts.

What should I avoid doing with HIIT?

High-intensity training experts recommend the following guidelines:

  • Don’t do HIIT more than 2-3 times per week
  • Don’t exceed 40 minutes of HIIT in a week
  • Don’t skip or shorten the recovery portion of each set
  • Don’t do HIIT on an empty stomach
  • Don’t do HIIT without an adequate warmup
  • Don’t do HIIT lifting lots of weight
  • Don’t bother with HIIT if your effort isn’t 100%

 

Can I do HIIT with weights?

Because of the high aerobic impact that high intensity training causes, you won’t realize the same sort of strength training benefits that you would doing normal heavy lifting.

You won’t get as strong or as muscular doing HIIT using weight training exercises compared to simply weight lifting normally and then performing your HIIT separately without using significant weight.

HIIT’s benefits spring from its effect on our cardiovascular & metabolic systems, and the preferred means to get there is with high aerobic intensity and light resistance.

 

What are the benefits of HIIT?

In addition to its fitness benefits, HIIT also improves our bodies’ health in several ways too.

Here are a few of those:

* Improves insulin resistance & lowers blood sugar

*Reduces fat including belly fat

*Improves aerobic fitness & our heart’s pumping efficiency (ejection fraction)

*Greatly boosts our resting metabolic rate for several hours after workouts

*Takes less than half the time as traditional steady-state cardio.

 

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Wrapping Up

I hope you found my research on how much HIIT per week we should do & on a HIIT workout’s optimal length useful to you, and I wish you well on your fitness journey.

Let’s go.

– greg

January 2021

 

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About heydayDo

heydayDo author Greg Simon
Hi I’m Greg Simon. Fitness training & nutrition researching since 1982. Organic food & wine grower. Surfer. Congenital heart disease survivor (so far). Read more…
heydayDo is my “fitness after 50” website that’s about embracing the physically active lifestyle as we get older.
 
I write about the fitness and health research I’ve found concerning the quality of life benefits that exercise and good nutrition provide.
 
When I get curious about something, I’ll dig into whatever sports science & medical facts there are on the topic to learn what’s real & what’s only hype. I also post my experiences product-testing & evaluating home gym equipment & fitness supplements.
 
 It’s an information-sharing, personal opinion blog of mine.
 
So if you’re looking for medical or nutritional advice, please consult with your doctor or health professional for that, since heydayDo does not provide medical advice.