One major advantage that kettlebells have over dumbbells is that you don’t need a wide range of weight increments to create a workout with them. One 16 kilo weight if you’re a man, or 8 kilo if you’re a woman, will get it done for most people. The following workout requires just one kettlebell and works the entire body. Note that, unlike what you see in most kettlebell workouts, we’re not having you do the Turkish getup and full swing—even though we’re well aware that they’re two of the most popular kettlebell exercises. Rather, we’ve modified these exercises to more user-friendly—but still supremely challenging—versions that will allow someone of any experience level to train safely and with optimal form.
Use this routine to build strength and burn fat now, and develop the requisite stability and mobility to graduate to more advanced exercises at a later date.
Perform the exercises as a circuit, completing one set of each in sequence without rest in between. When you’ve completed the entire circuit, rest 1–2 minutes, and then repeat for 3 total rounds.
Duration 20-25 minutes
Frequency 1-2x per week
Exercise strength training
Rest 1-2 minutes
Hold the kettlebell by its horns and drive your shoulder blades together and downward so your chest is open (think “proud chest”). Tuck your elbows in so your forearms are vertical.
Stand with feet a bit wider than hip-width apart with feet turned out slightly. Take a deep breath into your belly and twist your feet into the ground (imagine screwing them down without actually moving them) and squat, keeping your torso upright. Go as low as you can without your tailbone tucking under your butt.
2. Kettlebell One-Arm Row
Reps: 8 (each side)
Place the kettlebell on the floor and take a staggered stance with your right foot in front. Your foot should be planted just outside the weight. Dig the ball of your left foot into the floor behind you and bend your hips so your torso is angled about 45 degrees to the floor. Rest your right elbow on your right thigh for support and reach for the kettlebell with your left hand. Keeping your shoulders square, complete all your reps on one side and then repeat on the other side.
3. Kettlebell One-Arm Press
Reps: 5 (each side)
Stand tall holding the kettlebell in one hand at shoulder level. Root your feet into the floor as if you were preparing for someone to push you. Take a deep breath into your belly and brace your abs and glutes. Pull your ribs down and think “proud chest.”
Press the weight overhead with a vertical forearm. Note that your chin should be pulled back so that weight has no trouble clearing it. To lower the kettlebell, pull it back down into position—as if you were performing a pullup. Complete all your reps on one side and then repeat on the other side.
TIP: “Don’t get fixated on achieving a full overhead lockout right away,” says John Wolf, Onnit’s Chief Fitness Officer. “Just going to where your elbow is bent 90 degrees and holding it isometrically is a ton of work for most people.” If you need to arch your back, causing your ribs to flare in order to lock out your arm overhead, you’re not training the shoulder effectively. In that case, you may need to regress the movement to a floor press—lie down on the floor with your triceps against it and press upward from there (think of it as a bench press with a shortened range of motion).
4. Kettlebell Chest-Loaded Swing
Stand with feet between hip and shoulder-width apart and hold the kettlebell by its horns, pulling the bottom of the bell into your lower sternum. Draw your shoulder blades together and down (“proud chest”) and cast your eyes on a spot on the floor approximately 15 feet in front of you.
Take a deep breath and root your feet. Then bend your hips back, imagining being able to touch your butt to the wall behind you. Keep a long spine with your tailbone tilted slightly up. When you feel a stretch in your hamstrings, extend your hips and squeeze your glutes, tucking your tailbone under as you lock out.
5. Kettlebell Shoulder Halo
Reps: 8 (each direction)
Stand with feet between hip and shoulder-width apart and hold the kettlebell by its horns upside down—the bell should face up. Screw your feet into the floor and draw your ribs down. Think “proud chest.”
Begin moving the kettlebell around your head, being careful to maintain your posture and not bend your torso in any direction. Move slowly to avoid whacking yourself in the head. Make full circles and alternate directions on each rep.
6. Kettlebell Hip Halo
Reps: 8 (each direction)
Set up as you did for the shoulder halo but hold the kettlebell by the handle at arm’s length and make circles around your hips. Hand the kettlebell off from one hand to the other. Perform eight reps in one direction and then repeat in the opposite direction.
7. Kettlebell Around the Leg Pass
Reps: 5 (each direction)
Perform halos as you did around the hips but with your hips bent back so you move the weight around one knee at a time. Keep a proud chest—ribs down with a long spine. Perform five reps in one direction and then repeat in the opposite direction. Switch legs and repeat.
8. Kettlebell Chest-Loaded Swing
Repeat the swings as described above.
9. Kettlebell Single-Arm Squat to Press
Reps: 8 (each side)
Hold the kettlebell with one hand at shoulder level. Tuck your elbow in so your forearm is vertical. Perform a squat as described above, and then come up and press overhead.
10. Kettlebell Chest-Loaded Swing
Repeat the swing a final time.
While most people know that physical activity is healthy, it's estimated that about 30% of people worldwide don't get enough. Unless you have a physically demanding job, a dedicated fitness routine is likely your best bet for getting active. Unfortunately, many people feel that they don't have enough time to exercise If this sounds like you, maybe it's time to try high-intensity interval training (HIIT).
1. HIIT Can Burn a Lot of Calories in a Short Amount of Time
You can burn calories quickly using HIIT. One study compared the calories burned during 30 minutes each of HIIT, weight training, running and biking. The researchers found that HIIT burned 25–30% more calories than the other forms of exercise. In this study, a HIIT repetition consisted of 20 seconds of maximal effort, followed by 40 seconds of rest. This means that the participants were actually only exercising for 1/3 of the time that the running and biking groups were. Although each workout session was 30 minutes long in this study, it is common for HIIT workouts to be much shorter than traditional exercise sessions. This is because HIIT allows you to burn about the same amount of calories, but spend less time exercising.
2. Your Metabolic Rate Is Higher for Hours After Exercise
One of the ways HIIT helps you burn calories actually comes after you are done exercising.
Several studies have demonstrated HIIT's impressive ability to increase your metabolic rate for hours after exercise. Some researchers have even found that HIIT increases your metabolism after exercise more so than jogging and weight training. In the same study, HIIT was also found to shift the body's metabolism toward using fat for energy rather than carbs. Another study showed that just two minutes of HIIT in the form of sprints increased metabolism over 24 hours as much as 30 minutes of running.
3. It Can Help You Lose Fat
Studies have shown that HIIT can help you lose fat.
One review looked at 13 experiments and 424 overweight and obese adults.
Interestingly, it found that both HIIT and traditional moderate-intensity exercise can reduce body fat and waist circumference. Additionally, one study found that people performing HIIT three times per week for 20 minutes per session lost 4.4 pounds, or 2 kgs, of body fat in 12 weeks — without any dietary changes. Perhaps more important was the 17% reduction in visceral fat, or the disease-promoting fat surrounding your internal organs. Several other studies also indicate that body fat can be reduced with HIIT, despite the relatively low time commitment. However, like other forms of exercise, HIIT may be most effective for fat loss in those who are overweight or obese.
4. You Might Gain Muscle Using HIIT
In addition to helping with fat loss, HIIT could help increase muscle mass in certain individuals . However, the gain in muscle mass is primarily in the muscles being used the most, often the trunk and legs. Additionally, it's important to note that increases in muscle mass are more likely to occur in individuals who were less active to begin with. Some research in active individuals has failed to show higher muscle mass after HIIT programs. Weight training continues to be the "gold standard" form of exercise to increase muscle mass, but high-intensity intervals could support a small amount of muscle growth.
5. HIIT Can Improve Oxygen Consumption
Oxygen consumption refers to your muscles' ability to use oxygen, and endurance training is typically used to improve your oxygen consumption. Traditionally, this consists of long sessions of continuous running or cycling at a steady rate. However, it appears that HIIT can produce the same benefits in a shorter amount of time. One study found that five weeks of HIIT workouts performed four days per week for 20 minutes each session improved oxygen consumption by 9%. This was almost identical to the improvement in oxygen consumption in the other group in the study, who cycled continuously for 40 minutes per day, four days per week. Another study found that eight weeks of exercising on the stationary bike using traditional exercise or HIIT increased oxygen consumption by about 25%. Once again, the total time exercising was much different between groups: 120 minutes per week for the traditional exercise versus only 60 minutes per week of HIIT. Additional studies also demonstrate that HIIT can improve oxygen consumption.
6. It Can Reduce Heart Rate and Blood Pressure
HIIT may have important health benefits, as well. A large amount of research indicates that it can reduce heart rate and blood pressure in overweight and obese individuals, who often have high blood pressure.One study found that eight weeks of HIIT on a stationary bike decreased blood pressure as much as traditional continuous endurance training in adults with high blood pressure. In this study, the endurance training group exercised four days per week for 30 minutes per day, but the HIIT group only exercised three times per week for 20 minutes per day.Some researchers have found that HIIT may even reduce blood pressure more than the frequently recommended moderate-intensity exercise. However, it appears that high-intensity exercise does not typically change blood pressure in normal-weight individuals with normal blood pressure.
7. Blood Sugar Can Be Reduced by HIIT
Blood sugar can be reduced by HIIT programs lasting less than 12 weeks. A summary of 50 different studies found that not only does HIIT reduce blood sugar, but it also improves insulin resistance more than traditional continuous exercise.Based on this information, it is possible that high-intensity exercise is particularly beneficial for those at risk for type 2 diabetes. In fact, some experiments specifically in individuals with type 2 diabetes have demonstrated the effectiveness of HIIT for improving blood sugar. However, research in healthy individuals indicates that HIIT may be able to improve insulin resistance even more than traditional continuous exercise.
The allure of short, intense workouts is obvious. But is High-Intensity Interval Training (HIIT) really the only workout you need for good overall fitness?
By: Brock Armstrong
I was recently investigating a fancy new stationary bike that came on the market not that long ago. It uses a variation of High-Intensity Interval Training (HIIT). It’s a slick-looking bike, which appeals to my fashionista side. It also includes some interesting machine learning, which appeals to my inner nerd. And it boasts some pretty phenomenal health study results, which appeals to my inner coach. But despite all that, I still find myself scratching my head.
This is where the stumbling block starts for me. The bike’s website claims that the device is "clinically proven to give you the same cardio benefits of a 45-minute jog in under 9 minutes, with only 40 seconds of hard work."
Really? On a stationary bike? Where you aren’t using your arms at all, your skeleton is supported by a seat, and your legs are only moving through a biomechanically repetitive and limited range of motion? I find that claim dubious at best.
Before we get into some of the problems with HIIT, let’s clarify what it is.
WHAT IS HIGH-INTENSITY INTERVAL TRAINING (HIIT)?
HIIT involves alternating brief bouts of high-intensity exercise (30 seconds to five minutes) with shorter rest periods during a single exercise session. For most people, the allure of this type of training is that it promises shorter workouts, which still provide results that are equal to (or greater than) more traditional moderate-intensity training. HIIT is versatile enough to be used in all types of settings. It also packs a punch that can take some extra time to recover from.
Arguably, the most popular form of HIIT is the Tabata method. I wrote about that in an article called How to Use Tabata Training for More Than Just HIIT Workouts. Although the article you’re reading right now may seem like it’s putting HIIT down, I stand by my previous claims. Tabata training, if done correctly (and that’s a big if), is very demanding. The body responds to the stress of this workout by rapidly increasing its capacity to increase oxygen uptake, which is an important measure of fitness.
As I hinted at earlier, you do not need to do HIIT more often than once or twice per week. Doing it more often than two or three times a week can actually be counterproductive. If you are doing these workouts correctly, your body will need time to recover between sessions. The key to making any interval training effective is in the intensity. Which leads me back to the problems with HIIT.
HIIT Problem #1
"Cardiovascular fitness based on one particular activity is not the same as cardiovascular health in everyday life."
In biomechanist Katy Bowman’s book, Move Your DNA, she explains that “cardiovascular health comes when the entire circulatory system is used in a variety of ways to deliver oxygen to 100 percent of all cells of the body.” So, with that in mind, let's think about this bike. A stationary cyclist's cardiovascular fitness may allow them to pump a lot of blood to their legs for several hours (or just a few minutes on this device.) But at the same time, that cyclist's body may be providing lower blood supply to other parts of the body that remain still and supported during this short-but-intense exercise session. And that's a problem.
HIIT Problem #2
Most people aren't doing it right.
And by that I mean they're not working out hard enough.
I just did a search for HIIT and found a list of tips that I think are quite typical. Without pointing any fingers, here's what the website said:
The problem is that these aren't the same techniques used in the lab where all those amazing (and slightly hard to believe) stationary bike results were seen.
If you don't have enough PGC1a built up in your muscle, your body will not provide the necessary signal to improve your fitness. Building up that extreme amount of PGC1a requires a drastic depletion of glycogen (or storage carbohydrate) in the muscles. To induce that type of state, it takes a "fight or flight" type of sprint. That's the exact opposite of what tip #2 told us, which was to "leave some gas in the tank. "
So, if we follow the hype behind HIIT and also try to rely on it as a way to boost our fitness in only 9 minutes, done a few times per week (with only 40 seconds of hard work) but we also take the advice of leaving some gas in the tank, well, we'd likely be better off going for a walk.
HIIT Problem #3
It shouldn't be done in isolation.
When you read statements like "Implementing our protocol has been independently proven by the American Council on Exercise to smash government exercise guidelines," you could easily believe that riding your fancy new stationary bike, every second day, is all you need to do to be fit. That's not the case.
Only doing HIIT workouts for exercise is the equivalent of eating only broccoli for all of your meals. Sure, broccoli is yummy and good for you, but you'll miss out on lots of other enjoyable and nutritious foods if that's all you eat.
For this analogy, I am obviously asking you to think of providing movement for your body in the same way that you think of nourishing it with food. Think of HIIT like broccoli—it's a valuable source of nutrients, but it shouldn't be viewed as the one and only nutrition source necessary to be healthy.
I am not disputing the various scientific studies that show increases in oxygen uptake, drops in blood pressure, and increases in fat oxidation after using a device and protocol like the bike I mentioned earlier. But there is much more to fitness and health than just improving your blood test results.
There's much more to fitness and health than just improving your blood test results.
As I explained in my article Why Cross-Training Is Essential (and Improves Your DNA), including varieties of movement (or cross-training) in your fitness program allows you to vary the stress placed on specific muscles and your cardiovascular system. It has also been known to reduce the possibility of an overuse or repetitive movement injuries that can come from doing a single sport or a single intensity for every workout.
And how can you stay excited about your workouts if they're always done the exact same way, on the same piece of equipment, in the same location? You can't.
HIIT definitely has a place in my exercise regimen, but it's on an equal playing field with walking, strength training, mobility or flexibility, and recovery days.
HIIT can take your training and performance to the next level. Here’s everything you need to know about the popular exercise technique.
High-intensity interval training, or HIIT for short, was named one of the top fitness trends in the world for 2019, based on an annual survey by the American College of Sports Medicine.
This super hard, super effective style of training isn’t just the “it” workout of the moment—of the 13 years ACSM has been conducting this survey, HIIT also topped the list in 2014 and ranked in the top three for five consecutive years.
Why? Because it works, and it works fast. Whether you’re coming straight off the couch, training for a marathon, or even if you race for a living, HIIT training is good for your health and makes you fitter and faster.
What Are the Benefits of HIIT?
New studies on the benefits of HIIT make the news on a regular basis. Take, for example, this one from the November 2018 issue of American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. Researchers found that just two minutes of sprint interval training (in this case, four 30-second max-effort sprints followed by four and a half minutes of recovery for a total of 20 minutes) improved mitochondrial function—when your cells can change fuel to energy quickly, a benchmark for good health and exercise performance—just as well as 30 minutes of moderate exercise in a group of active men and women. In other words, busting out two minutes of really hard running can give you the same fitness benefits as slogging through 30 minutes at a steady, moderate pace.
What HIIT Means for You
Most of us already run a lot because as endurance athletes, that’s our thing. But even if you’re already fit, you can still reap measurable benefits from adding HIIT to your training regimen, says exercise physiology professor and coach Paul Laursen, Ph.D., endurance coach, author of The Science and Application of High-Intensity Interval Training (HIIT), and contributor to HIITscience.com.
For runners who like to go long, HIIT can be part of a smart base-building strategy. “Your base comes down to your mitochondrial capacity,” Laursen says. “Longer, lower-intensity exercise increases the number of mitochondria in your cells, which is why people perform long, steady endurance exercise to build base. But high-intensity training makes those mitochondria more powerful,” he says, noting that research also shows that high-intensity exercise performed regularly can stimulate the production of mitochondria, as well.
“Our research found that when well-trained cyclists performed two interval sessions a week for three to six weeks, their VO2 max, peak aerobic power output, and endurance performance improved by 2 to 4 percent,” he says.
Plus, recent research out of Australia suggests that doing your HIIT workouts in the evening won’t mess with your shuteye—and it could even curb your appetite after a session.
To help you get started, try any of these high-intensity interval run workouts.
On the Track
High-intensity track sessions move the muscles through the full range of motion, improving elasticity and enhancing coordination between your nervous system and muscles. With time, you’ll develop a more efficient stride at all your paces, says Joe McConkey, M.S., an exercise physiologist and coach at the Boston Running Center.
Begin with two 100-meter accelerations that include 40 meters at top speed, with 2 to 3 minutes of walking or jogging between. Build to 6 x 150 meters hard, including 80 meters at top speed, with 3 to 4 minutes jogging or walking rest. Over time, increase the number of repeats to 10, lengthen reps to 300 meters (running nearly the entire distance at top speed), or reduce the rest interval to 1 minute.
On the Trails
It adds to the challenge, but running fast over softer, less-groomed terrain like bridle paths, trails, or grass can increase agility and athleticism—or your ability to run with the “precise amount of power, speed, and coordination needed for efficient movement,” McConkey says.
Because of the terrain and potential strain on your leg muscles, ease into off-road workouts. Do five 30-second pickups at a moderate intensity during an easy 20-minute run, and build up to ten 60-second near-all-out bursts during a 40-minute run. From there, progress to running five cycles alternating 30 seconds of all-out running with 90 seconds jogging, then to 10 cycles alternating one minute easy with one minute super hard. Just be careful not to trip.
On the Hills
Inclines are a great venue for super fast speedwork. Compared with a flat surface, hills reduce the impact on your legs and limit your range of motion, thereby lowering the risk of strains and pulls. Plus, hill repeats build muscle power, which helps you run more efficiently on level ground, says McConkey.
On an incline, start with three 30-second moderate repeats and walk down the hill for recovery. When this becomes comfortable, progress to 4 x 1 minute near all-out efforts with a downhill jog and an additional 30 to 60 seconds jogging or walking rest. Over time, add additional reps, extend effort length up to two minutes, and aim for steeper hills, says McConkey.
What is high intensity interval training?
High intensity interval training (HIIT) is when you alternate between high and low intensity exercise(s) or between high intensity exercise and a short period of rest.
For example, a short sprint up a flight of stairs followed by a walk back down is interval training. Or a set of burpees followed by bodyweight rows.
If you’ve ever participated in HIIT, you know that alternating bodyweight conditioning exercises for 15 minutes can be a lot more challenging than a walk around the block.
Why is high intensity interval training so important?It’s physiologically impossible to sustain maximal intensities during exercise for an extended amount of time. This is because of how our bodies use fuel.
Let’s say I tell you to go outside and run as fast as you can for 20 minutes.
Stage 1 – Phosphocreatine
OK! The first 10 to 20 seconds are going great! You’re sprinting like the wind! That’s because you’re using a high-intensity energy source known as phosphocreatine.
Stage 2 – Lactic acid and anaerobic glycolysis
After about 20 seconds, your phosphocreatine start to run low, and anaerobic glycolysis would predominate. At this point, more lactic acid would be produced and used as a fuel source.
You’re still be running as hard as you can, but you’d be slowing down, and your lungs are working overtime.
If you were a member of the Canadian Olympic Hockey team or an elite speed skater, you could probably maintain this for up to 10 minutes. But those who are not well conditioned would need to slow down and even stop. If this is your first time off the couch, you might even consider throwing up, thanks to the change in blood pH levels.
Well, it looks like the spirit is willing but the flesh is weak. 20-minute sprint challenge: FAIL.
So why can’t you work at maximal intensity for an extended amount of time?
Oxygen: The molecule that makes the magic
One reason is the supply and demand of oxygen when working so hard.
Nature is full of trade-offs. In this case, we trade efficiency for intensity.
When you work at a lower intensity (such as during a brisk walk), aerobic metabolism predominates.
Your body uses oxygen to break down carbohydrate and fat for energy. This is very efficient, but you can’t work at top speed. With aerobic metabolism, you gain efficiency but lose intensity. Evolutionarily, this would be useful for traveling long distances while foraging for food or water.
On the other hand, when you work at a higher intensity (such as sprinting), anaerobic metabolism predominates.
Your body can’t get oxygen to where it needs to go fast enough. This is very inefficient, but it lets you produce short bursts of speed or high energy — very handy when you’re running away from a sabre-toothed tiger or a rock-wielding Grok.
So, we have these two systems, both of which have their own advantages and disadvantages. What if we could have our cake and eat it too? (Or, in this case, lose the fat we gained by eating the cake in the first place.)
With HIIT, you alternate short bursts of very intense exercise (such as 10-20 sec of sprinting) with periods of lower intensity (such as 1 min of walking).
HormonesIn addition, hormone release during exercise depends on exercise intensity.
Gentle movements such as yoga, tai-chi, or a pleasant stroll outside can lower stress hormones.
But when you approach 85 to 95% of VO2max, growth hormone, testosterone, endorphins, epinephrine (adrenaline), norepinephrine (noradrenaline), cortisol, and aldosterone all increase. These hormones all have effects on body composition and anabolism.
What you should know about HIITExercise can range from gentle movements to maximal efforts. HIIT and heavy weights can elevate stress hormones.
Most every high intensity physical activity is a state of “crisis” in the body. It endangers oxygen supply to tissues, increases body temperature, reduces body fluids and fuel stores, and causes tissue damage.
Intense exercise creates endocrine and defense reactions that are similar to those elicited by low blood oxygen, high blood carbon dioxide, acidosis, high body temperature, dehydration, low blood sugar, physical injury and psychological stresses.
Hormonally, your body basically freaks out. Then it brings out the big guns to deal with the problem. High intensity exercise stresses the body so much that it’s forced to adapt.
As Nietzsche gasped during a 20-rep squat set, “That which does not kill me makes my quads bodacious.” (It makes more sense in German.)
HIIT is excellent for:
How to do HIIT
There are many ways to do HIIT. All you need to remember is the basic principle: Alternate short bursts of very high intensity with periods of recovery/low intensity.
The longest 4 minutes of your life: The Tabata studyOne of the most famous studies of HIIT is known as the Tabata study. In this study (see abstract below), subjects performed rowing intervals: 20 sec of ultra-fast rowing alternated with 10 seconds of relaxed recovery rowing, for a total of 8 intervals, or 4 minutes.
At the end of the study, participants showed a 28% increase in anaerobic capacity along with a 14% increase in V02max. Pretty impressive!
The “Tabata protocol” — 20 seconds on, 10 seconds off — has become one of the most common methods of doing HIIT.
Weighted circuitsUsing resistance exercises can be a very effective method of doing HIIT.
To use resistance training, choose compound exercises that are good “oxygen suckers”, such as:
Combo exercises are also good choices. For instance:
You can also combine resistance exercises with “cardio” type exercises.
Customizing HIIT for your goalsYou can mix up your HIIT choices to avoid overtraining and overuse injuries, and to keep things fresh and interesting.
If you’re a competitive athlete who needs energy systems work for your sport, incorporate some sessions of sport-specific HIIT work. For example:
You can also vary the length of your intervals.
If you’re new to HIIT, opt for shorter high intensity periods and longer low intensity periods.
And note: “high intensity” means “high intensity for YOU”. If you’re a beginner, a fast jog or uphill walk for 10 seconds is a better start than trying to handle an all-out sprint workout.
Don’t forget: Perform an adequate warm up and cool down when performing HIIT.
For extra credit
The benefits of HIIT are exercise specific. If you do squat jumps and running, you get better at squat jumps and running.
You can maximize your HIIT performance by using non-competing exercises. Instead of doing split squat jumps alternated with squat jumps, which use the same muscles, you could pair up bodyweight rows and squat jumps.
With really intense bouts of exercise, the body’s energy requirement can increase 2 to 20 fold!
During the first 1-2 hours after intense exercise, your body’s energy requirements remain high.
So what is high intensity? Well, during your next sprint, envision a crazy grizzly bear chasing you. That should suffice.
HIIT will not only improve body composition, it may extend your life. The Harvard Alumni Health Study, a 4-year study of more than 17,000 men, found that only vigorous – not moderate — exercise reduced risk of death.
In the fitness world, the word “miracle” gets thrown around like a two-pound dumbbell. But when it comes to high-intensity interval training (HIIT), a very short workout, the benefits you’ve heard about are both legitimate and—we’ll say it—miraculous.
HIIT is a combination of brief, very-high intensity bursts of cardio exercise followed by equal or longer periods of rest. Think 30 seconds to a minute of sprinting, followed by a minute or two of walking or slow jogging. Repeat this cycle for just 10 minutes, and you’ll complete a HIIT workout.
“We now have more than 10 years of data showing HIIT yields pretty much the exact same health and fitness benefits as long-term aerobic exercise, and in some groups or populations, it works better than traditional aerobic exercise,” says Todd Astorino, a professor of kinesiology at California State University, San Marcos, who has published more than a dozen study papers on HIIT.
Whether your goal is to improve your fitness, lower your risk for cardiovascular disease, lose weight, strengthen skeletal muscle or help get your blood sugar under control, a few minutes of HIIT seem to be as effective as much longer periods of moderate-paced running, cycling, swimming or other forms of traditional cardio. For well-trained athletes, HIIT may be the best way to elevate your physical performance.
One small study of healthy but sedentary people found just one minute total of HIIT performed three days a week for six weeks was enough to significantly improve blood sugar scores and aerobic capacity, a measure of physical fitness. The study participants completed 10- to 20-second bouts of “all-out” cycling on a stationary bike, each broken up by a couple minutes of rest. The total workout time, start to finish, was 10 minutes.
Other research finds that HIIT may outperform traditional cardio when it comes to fat loss. A HIIT-induced surge in your body’s levels of growth hormones and other organic compounds “can increase fat burning and energy expenditure for hours after exercise,” says study author Stephen Boutcher, an associate professor of medical sciences at the University of New South Wales in Australia.
It doesn’t just work for the young, fit and healthy. Among people with heart disease, HIIT improves cardiorespiratory fitness nearly twice as much as longer stretches of moderate-intensity running, cycling or other aerobic exercises, one review study concluded.
How can HIIT do so much good in so little time? During very intense exercise, “the heart cannot pump enough blood to satisfy all the muscles,” says Ulrik Wisløff, a HIIT researcher and head of the cardiac exercise research group at the Norwegian School of Science and Technology. This lacking oxygen delivery to the muscles starts a “cascade of molecular responses in most organs of the body” that produces a greater training response than more leisurely bouts of exercise, he says.
Exercise of any intensity switches on genes that increase the growth of mitochondria—the power generators of the cells—and triggers all of the other beneficial biological changes linked with physical fitness, says Astorino. “But to activate these genes with traditional cardiovascular exercises, you have to do fairly large or long bouts,” he says. With HIIT, it appears that even very short bouts of training can switch on those genes, so it’s an efficient workout.
HIIT can work for a wide range of people. But how you should practice it depends on your fitness level.
The key to HIIT is pushing your heart rate up above 80% of its maximum, Astorino says. “Subtract your age from 220 to estimate your maximal heart rate,” he says. (A heart rate monitor can provide an accurate assessment. But if you’re really sucking wind after pushing yourself, you’ve probably hit your target, Astorino says.)
If you’re fit, try sprint interval training. After walking or slow jogging for a few minutes to warm up, sprint as hard as you can for 30 seconds, then recover for four minutes by walking or jogging slowly. Complete four to six sets of this sprinting-recovery program. (For an even faster version, keep the warmup, then complete three sets of 20-second sprints, each separated by two minutes of recovery, Astorino says.)
If you’re overweight or obese and you haven’t exercised in months, sprinting isn’t necessary (or safe for your joints). Instead, 30 seconds to four minutes of brisk walking on an inclined treadmill or hill should be enough to push your heart rate up into the HIIT zone, Astorino says.
You can also practice these programs with a stationary bike, rowing machine or in the pool. Any form of cardio can push your heart into the HIIT zone, Wisløff says. (This fact sheet from the American College of Sports Medicine offers more in-depth details on how to design a HIIT program.)
And yes, HIIT is safe. Wisløff and colleagues analyzed nearly 50,000 hours of HIIT data collected from cardiovascular disease patients in Norway. In seven years of data, he turned up just two instances of (non-fatal) cardiac arrest.
He says people with unstable angina or serious heart issues should speak with their doctor first. But, in general, “it’s much more dangerous not to perform HIIT than to perform it,” he says.