Have you ever wondered about the benefits of High-Intensity Interval Training (HIIT)? It seems everyone and their grandmother is doing HIIT these days.
High-Intensity Interval training – HIIT – is doing short, intense bursts of activity followed by a rest period.
The original science dates back to the ‘90s when Dr. Izumi Tabata, a researcher with the National Institute of Fitness and Sports in Kanoya, Japan studied interval training on a cycle ergometer (a fancy stationary bike).
HIIT workouts are still often referred to as Tabata Training.
Dr. Tabata published his research in 1996 showing that an ultra-short interval routine was effective at increasing aerobic and anaerobic fitness in only 4 minutes of exercise – 5 days a week.
He used bouts of 20 seconds of cycling at all out maximum intensity followed by 10 seconds of rest.
Eight bouts and you’re done.
These simple sprints were short, but effective spawning more research into the benefits of HIIT.
Subsequent research, now almost 20 years later, continues to demonstrate numerous benefits.
Here is a list of the evidenced-based benefits HIIT has to offer.
#1 Benefit of HIIT – Save Loads of Time
The most commonly sited barrier to exercise is lack of time.
HIIT can solve this problem. In fact, studies have found that HIIT can give you the same or even greater benefits in about half the time.
Let me repeat that for emphasis.
HIIT can give you equal or greater benefits in half the time.
As an example, studies have found increased cardiorespiratory fitness, strength and weight loss in HIIT groups that work out for only 20 minutes. This is compared to a group doing moderate continuous exercise for 40 minutes.
Half the time.
Researchers are actively searching for the minimal work load – the least amount of time needed to get the fitness benefits.
The Tabata cycling routine was extremely time efficient showing benefits in only 4 minutes of exercise. Cycle for 20 seconds hard at 100% max, than rest for 10 seconds. Perform only 8 bouts of this and be done for the day.
This routine was performed 5 days per week in the original study, which is 20 minutes of exercise PER WEEK.
Tabata training would be a highly efficient use of your time.
More recent research has found that only 3 minutes of intense exercise per week will give you benefits.
Yes, only 3 minutes.
The overall time commitment was 30 minutes per week (warm up, burst and rest intervals and cool down). Ten minutes, 3 times per week, but only 3 minutes of intense exercise needed to show improvements. After only 6 weeks of this minimal viable exercise improvements were found in aerobic fitness. Muscle adaptations occurred such as increase in muscle mitochondrial enzymes and muscle strength.. There was also improvements in blood sugar control and blood pressures.
Gimme a break. You (and I) have no excuse.
#2 Benefit of HIIT – Burn fat and lose weight
If you need to lose weight there may be no better exercise than high-intensity interval training.
HIIT appears to help get rid of abdominal fat preferentially.
In one study, HIIT was compared to moderate continuous exercise on the bike. Only 20 minutes of HIIT was found to be superior to 40 minutes of moderate continuous exercise in subcutaneous fat as well as abdominal fat.
In only 15 weeks the HIIT group lost 5 pounds, while the moderate continuous group actually gained fat.
You can lose between 10 and 40% of your abdominal fat using HIIT to exercise.
How does HIIT accomplish this?
There appears to be at least 4 responsible mechanisms that explain how HIIT can help with weight loss.
First, HIIT increases levels of adrenalin hormones (norepinephrine and epinephrine).
With each burst of activity it appears that more norepinephrine and epinephrine hormones are released.
These fight or flight hormones open up fat stores so the body can use them for energy.
Secondly, HIIT exercise improves insulin sensitivity.
With improved sensitivity the body needs less insulin. Insulin is an energy hormone. Not only does it control blood sugar use, but it is a key to open the door to allow fat into the fat cell to be stored.
With less insulin around – less fat is stored.
Third, the bursts of activity in HIIT strengthens thigh muscles.
The HIIT exercises appears to also cause an increase in mitochondria in the muscle, which are the tiny energy burning organelles in each cell of our bodies. With more mitochondria the muscle burns energy and fat more efficiently. Moderate continuous exercise does not seem to have this effect. This is likely why Olympic long distance runners are thin, while Olympic sprinters are bursting with muscle.
Forth, HIIT is associated with an increased “Excess Post-Exercise Oxygen Consumption (EPOC).”
EPOC is the “afterburn effect” of exercise.
Essentially after the body exercises it needs to recover. This recovery takes energy and burns more calories. HIIT exercise has been associated with more calories burned during EPOC and may therefore have a powerful “afterburn effect” burning more calories.
Lastly, HIIT is associated with appetite suppression.
Nesfatin-1 is a molecule found in the hypothalamus of the brain that helps to regulate hunger.
Elevated nesfatin-1 levels increase the sense of fullness.
One study found that HIIT causes a significant increase in nesfatin-1 levels, an effect not found in moderate continuous exercise. This suggests HIIT may increase nesfatin-1 and help suppress the appetite.
#3 Benefit of HIIT – Add muscle and strength
Muscle is good.
Muscle helps you to stay functional in life.
Do you want to travel and hike Machu Pichu someday?
How about a task much simpler.
Do you do chores around the house?
I do . . . occasionally. And it takes a bit of muscle to haul a basket of clothes up the steps.
If you are young you may laugh and think I’m crazy, but I guarantee you that someday hauling baskets of clothes up a flight of stairs will be challenging.
In fact, the most common reason I need to put my patients in the nursing home is not because of a disease but because they are weak, frail and they fall. They cannot get up. Their muscles are weak and their balance is poor because their muscles have dithered away.
Strength is everything when you no longer have it. Strength wains over the years if it is not protected. The technical term for muscle waisting over the years is sarcopenia.
You need to prevent this . . . and HIIT can help.
Studies have found the HIIT helps to increase strength. Most of the cycling studies include strength testing. Often simply testing knee extension, which is straightening the leg against a resistance. When HIIT is compared to moderate continuous exercise it always wins in the muscle category. Strength of the thigh muscle improves.
Even a simple interval walking program was found to increase strength in the leg muscles where the continuous walking group did not.
Related: HIIT Training for Weight Loss
#4 Benefit of HIIT – Minimal Equipment Needed
HIIT training can be done virtually anywhere. HIIT has been studied the most for cycling on a stationary bike and on treadmills.
However, I have read articles on running, walking, elliptical and even Burpees . . . all of which show benefits and usually superiority to a matched form of continuous exercise.
This gives you plenty of options, none of which require multiple machines, weights or pulleys.
You need a pair of shoes.
This is the simplest, most cost effective way to do HIIT. With shoes you can do a walking interval program, Burpees or sprint intervals.
If none of that interests you, then you’ll need a stationary bike, treadmill or an elliptical.
Now, HIIT has gone mainstream and every workout guru seems to refer to their new “Tabata” workout.
Often this is a circuit program doing a variety of exercises for 20 seconds followed by 10 seconds of rest.
Even the famous trainer Bob Harper of Biggest Looser fame has a Tabata circuit workout with his new Afterburn program (amazingly branded Black Fire – a name that demands results).
I’m sure the workout is effective.
However, these variations are not resembling the original research in any way.
I would never prescribe a medication in a dose not tested.
Why would I fail to have the same standard for an exercise prescription?
Exercise is medicine.
It deserves the same attention to details.
When I prescribe a walking program – it’s 3 minutes fast, 3 minutes of recovery and repeat for 50-60 minutes – because that is how it is studied!
If a medication should be taken at bedtime, take it at bedtime.
If 20 seconds of cycling followed by 10 seconds of rest for 8 bouts is your workout as Tabata was studied, then stick to that.
Avoid the urge to do pushups for 20 seconds followed by rest, then overhead rows for 20 seconds . . . this is a circuit program for weight lifting and not a Tabata routine.
So, remember your options – sprint, walk, treadmill, elliptical, Burpees.
Anything else and it’s unlikely to have been studied and may not accomplish the goal you set out for.
#5 Benefit of HIIT – You can do HI(IT) anywhere
Imagine your traveling to Chicago on just another business trip.
There you are after a sales call back at the hotel for the evening. You need a way to burn off that travel fare that has added to your waist line.
Have you ever thought to turn to a HIIT exercise?
When I am traveling I do HIIT on a treadmill.
Treadmills are everywhere . . . as are ellipticals and stationary bikes.
No hotel fitness center lives without one of these.
And if you cannot find a machine, then just lace up and walk or run.
This is the power of HIIT.
The equipment is universal and simple. If you cannot find a machine to work on – there are plenty of other options.
I grab a treadmill at the hotel – sprinting on busy downtown street is just not so easy – and people look at me funny.
No fitness center?
Then catch the stairs.
This strays a bit technically from HIIT, but you can sprint upstairs for several flights and then walk down.
Don’t worry about others seeing you – you’ll be the only one taking the stairs.
Sprinting upstairs is grueling and terribly effective.
Don’t injure yourself though. If you cannot run, hike up the stairs with big long steps – I guarantee lung burning and wobbly legs.
You see, with imagination HIIT can be done anywhere.
#6 Benefit of HIIT – Lowers your blood sugar
Type II Diabetes, the most common diabetes, is a problem with insulin resistance – a result of excess fat.
Most patients with Type II Diabetes Mellitus are overweight or obese. Patients with pre diabetes are on the verge of developing diabetes. Pre-diabetics are also mostly overweight or obese.
HIIT improves measures of blood sugar control.
Walking programs utilizing HIIT – 3 minutes of fast paced walking followed by 3 minutes easy walking – showed improvements in insulin sensitivity.
A study out of the journal Diabetologia showed that Type II diabetics completing an interval walking program had improvements in insulin sensitivity, while the continuos walking group in this study showed no improvements.
This suggests that there is magic in the intervals that improves insulin sensitivity.
HIIT seems to trigger changes in the muscle that improves it’s ability to process sugar.
This evidence has been compelling enough for me to recommend HIIT programs to my patients.
If you have been diagnosed with pre-diabetes or diabetes you may want to consider a HIIT program. Discuss this with your personal physician. Those with diabetes are at a higher risk for heart disease and so it is recommended to have a screening EKG done prior to engaging in a vigorous exercise.
If you are already walking, consider an interval walking program.
#7 Benefit of HIIT – Improve your blood pressure
Do you have high blood pressure? If not, do you know someone who does?
I would not be surprised if you or someone you know has high blood pressure.
It’s common. In fact, about 1/3 rd of Americans have hypertension – this is about 70 million people.
Not a small problem. In fact, this is the health problem I go to battle with everyday. This is why I put my hard hat on every morning.
Hypertension (high blood pressure) is a blood pressure that is greater than 140/90 mm Hg.
The top number is the systolic blood pressure, which is the pressure that occurs when the heart pumps. The diastolic blood pressure is the pressure when the heart relaxes, and thus a lower number.
Should you care if you or your loved ones have hypertension?
Decreasing the systolic blood pressure by only 2 mm Hg decreases death from stroke by 10% as well as the risk of death by heart attack by 7%.
Only 2 mm Hg could be the difference between life, death or disability.
Of course you could just take a medication. But why not do something simpler, less expensive and with fewer side effects?
You guessed it my wise reader . . . exercise.
Exercise will reduce the blood pressure by at least 2 mm Hg and up to 14 mm Hg. Quite a powerful medicine in fact.
HIIT may have a special benefit for your blood pressure control.
Studies have found that HIIT is on par with moderate continuous exercise in it’s beneficial effects on blood pressure.
However, HIIT has been shown to improve arterial blood vessel stiffness.
The moderate continuous exercise did not have this same effect.
This suggests that HIIT may not only help to lower blood pressure to a similar degree as the standard exercise, but may also help to turn back the clock and loosen up stiff vessels.
It’s the hardening of the arteries that causes more hypertension and heart disease, but HIIT may just help to reverse this.
#8 Benefit of HIIT- Save your heart
HIIT helps your heart.
This has been proven over and over in healthy patients.
Much of the research we have previously discussed. Anytime there are improvements in aerobic fitness, the heart has become stronger.
What about those with heart diseases?
If you have heart disease you may be wondering . . . can I even do HIIT?
I mean isn’t HIIT for the elite athletes? Won’t my heart give out, explode or go into an arrhythmia?
HIIT has even been studied for cardiac rehab. So far, studies have proven that it is just as safe as moderate continuous exercise.
This is the type of rehab you do if you survived a heart attack and need to pump up your heart to make it stronger.
HIIT has been studied on heart patients mostly on the treadmill.
HIIT on the treadmill appears to be safe and possibly more effective than moderate exercise in stable heart disease patients (at least in one small study).
A study from the American Heart Journal showed that a process called “re-stensosis” – plaque build-up in stents – can actually be reversed by HIIT.
So, it’s possible that HIIT can remove or at least prevent plaque buildup.
How about bypass patients? These are the patient with such severe heart disease that they required a surgery to put new vessels into their heart to “revascularize” it.
HIIT has been studied in these patients and found to be beneficial, and maybe superior to regular exercise.
Even older patients in their 70’s and 80’s with heart failure can benefit from HIIT.
How about the sickest heart patients . . . those with a heart transplant.
HIIT was found in this study to be safe and effective at improving aerobic fitness even in heart transplant patients.
All around, HIIT seems to help the heart and maybe superior to regular exercise for cardiac rehab patients. More research is needed.
If you have a heart condition you should discuss this with your cardiologist or primary physician before embarking on an exercise program.
However, research appears to support that HIIT is both safe and effective.
#9 Benefit of HIIT – A Workout you will love
If you are like most Americans, however, you probably would rather sit on the couch and avoid any physical activity.
Another benefit of HIIT is that it’s actually enjoyable. At least it’s a preferred workout when compared to other forms.
Look at it this way.
Would you rather workout out at a constant moderately vigorous pace for 40 minutes or would you rather alternate bursts of intense activity followed by periods of recovery . . . oh and for only 20 minutes?
I know what I would choose.
Turns out there is some research on this to validate my feelings.
The School of Health and Exercise Sciences at the University of British Colombia Canada studied whether HIIT is as enjoyable as other exercises.
The HIIT exercise was found to be more enjoyable than the vigorous intensity exercise.
When compared to continuous moderate exercise, HIIT was found to be as enjoyable.
However, when asked what exercise they would prefer – 24 participants in the study chose HIIT.
Only 13 preferred continuous moderate exercise and a mere 2 preferred continuous vigorous exercise.
Almost twice as many participants chose HIIT – after the fact.
How could this be? Isn’t HIIT too intense for people?
I think people quite naturally like to workout in bursts.
HIIT is like a game. We play as kids in bursts of activity.
This is natural and maybe evolutionary. We hunt in bursts of activity. Mammals, such as cubs, play in bursts of activity by frolicking in play fights. This is training.
When humans are working out there is the psychological game of getting to the next interval that I think is more interesting and rewarding than a monotonous slog through a 40 minute jog.
Also, these bursts of activity likely sets off hormones that make us feel good. We know that adrenaline hormones are released more with each burst of activity.
Lastly, it’s just motivating to get a good workout in such a short time.
But those are my thoughts – can’t back it up with reams of research . . . yet.
I think if you give it a try you will love HIIT like I do.
Related: Why you love HIIT workouts
There is a lot to love about HIIT.
You should consider HIIT workouts if you have heart disease and especially if you have high blood pressure or are on the verge of diabetes.
Remember that the intensity of your exercise matters.
Use these benefits as motivation to get started today.
The only thing that matters is your next action.
- Minimal Viable Exercise
- Tabata Workout Routine
- HIIT for Weight Loss: The Science Explained
- One Weight Lose Benefit of HIIT: Appetite Suppression
- Should you treat your high blood pressure with HIIT exercise?
- An Interval Walking Program: To lose weight, get strong and beat diabetes
- HIIT Burpee Workout
- HIIT on the Elliptical
- Why you love HIIT workouts
- physical-activity-120112-M-2021D-019 by Military Health on Flickr
- The Absurdity of Time [Explored] by Jason Devaun on Flickr
- Fat Belly’s by Sean Benham on Flickr
- Muscle: Skeletal Muscle Cell by Open Michigan on Flickr
- Treadmill by Jeff Blackler on Flickr
- Chicago Theatre by Kevin Dooley on Flickr
- A little sugar in my bowl by Umberto Salvagnin on Flickr
- Project 365 #134: 140511 Under Pressure! by Pete on FLickr
- Broken Heart Grunge by Nicolas Raymond on Flickr