What’s the best cardio for weight loss?
The common wisdom circulating the gym crowd is that weight loss comes down to a “more is better” approach. If you lose a little weight doing 30 minutes of cardio per day, you can lose more weight by doing 40 minutes of cardio. If you see results from pushing yourself at 80% effort, you can get faster results by pushing yourself 90% instead.
More can be better, and more intensity is certainly important. But if you’re looking at increasing your cardio training to boost weight loss efforts, there are some important things you should know about the different types of cardio.
Big picture: there are two main types of cardio. The first type is “steady state” cardio, where you move at the same pace for the duration of your workout. The second type is “interval training,” where you mix periods of low, medium, or high intensity with periods of little to no work.
Both types of cardio – steady state and interval training – have their time and place. This article will explain the differences between the different cardio training methods and answer the age-old question, “what cardio is best for weight loss?” Let’s dive in!
HITT Me With Your Best Shot: High-Intensity Interval Training
What we commonly refer to as “HIIT” training isn’t actually high-intensity. According to the National Academy of Sports Medicine, there is a “general lack of understanding within the fitness industry of what truly constitutes HIIT training… what many describe as HIIT is more likely high-volume interval training, or, in a best-case scenario, variable-intensity interval training.” (1)
What do all those acronyms mean, and what’s the difference between these training styles?
Let’s unscramble the interval training alphabet soup:
- HIIT – high-intensity interval training
- HVIT – high-volume interval training
- VIIT – variable-intensity interval training
True HIIT originated in the world of sports conditioning. Its purpose as a training modality is to increase athlete’s size, strength, speed, and overall performance on the field or track. True HIIT involves specifically overloading certain movement patterns and energy systems (we’ll get into that, too).
For example, a power athlete like an NFL offensive lineman or an Olympic weightlifter with a 225-lb one-repetition max power clean would train that movement at near maximal loads and rates with the sole purpose of improving his or her power production.
Likewise, a sprinter could repeatedly run the 40-yard dash as quickly as possible (resting sufficiently between attempts) in order to improve their sprinting capacity. The key here is “resting sufficiently” between each 40-yard dash attempt.
Both of the above examples represent training to increase performance. The kind of “HIIT” the average person does in the gym is more likely to be sub-maximal. This more sustained work trains our capacity for volume.
What About HIIT Boot Camp Classes?
Let’s say you go out for a “high intensity” run or to a boot camp workout. For the first 20 seconds or so, your body relies on a fast-acting energy source called phosphocreatine. After about 20 seconds, your phosphocreatine supplies run low, so your body begins to rely on “anearobic glycolosis” to produce energy anaerobically (without oxygen). This process produces lactic acid as a waste product of energy production – that’s the “burn” you might be starting to feel.
Even if you continue to sprint as fast as you can, you’re going to start slowing down because your body can’t buffer all of the lactic acid produced during sprinting, nor can you get enough oxygen to power a true high-intensity effort.
Contrast this with walking, which is low-intensity and uses the aerobic (“with oxygen”) energy pathway. You can probably walk for 20, 30, 60 or more minutes without slowing your pace very much because the aerobic system is highly efficient at powering low-intensity movement.
So… those “HIIT Camp” classes? Yeah, you’re not doing high intensity interval training for 30-plus minutes. It’s just not possible to sustain high intensity movement for such a long period of time. Those classes would more accurately be called “high volume” interval training because the amount, or volume, of work done during the class is higher than going for a walk or jog.
High-Volume Interval Training
High-volume interval training involves doing a lot of work in a specified amount of time. The intensity is necessarily “sub-maximal” because, as discussed above, your body can’t produce energy to power high-intensity exercise for longer than 20 seconds via phosphocreatine or 2-3 minutes via anaerobic glycolosis.
Where true HIIT requires long rest periods so that your fast-acting energy systems have time to recover between high-intensity efforts, HVIT generally uses longer working periods and shorter resting periods.
Does that mean HVIT is less effective than HIIT? Not at all! It’s simply meant to accomplish a different training outcome. Instead of training for power/performance like HIIT, HVIT is well-suited for increasing your work capacity and fat burning.
So, yeah, you’re probably not doing true HIIT intervals, but that doesn’t mean your boot camp classes are totally useless. Just keep in mind that the idea is to do as many reps as possible in the time given. Your goal should be to do more work (more volume) in the next class. That’s how you ensure progress and avoid plateaus.
Variable-Intensity Interval Training
Variable-intensity interval training is fairly similar to HVIT, but instead of resting in between efforts, you alternate between periods of hard work and periods of easy work. For instance, a 45-second all-out bike sprint followed by 45-60 seconds of mobility drills.
The benefit to this type of interval training is that you still get to use the “rest” interval to recover, but you’re also using that time to keep moving. This can be a great option for people just starting out in the gym who haven’t achieved levels of conditioning suited to super-intense efforts. The VIIT method keeps you moving throughout the workout, and you can even throw in some low-skill-level drills to improve flexibility, mobility, or core strength in between your more intense efforts.
Steady State Cardio
Most steady state cardio is what I will term “M.I.S.S.” because people perform their workouts at moderate intensity. I completely made up this acronym to illustrate how most people “miss” the mark when they try to use only this type of cardio for fat loss.
You see, moderate-intensity steady state cardio is nearly useless for weight loss. Spending sixty minutes or more plodding along on a treadmill or elliptical might seem hard at first (if you haven’t been working out lately), but your body is really good at adapting to the treadmill torture you’re putting it through.
In order for such a regime to be effective, you would have to continue to add minutes to your workout each week. Ain’t nobody got time to spend hours on the treadmill to burn a couple dozen measly calories!
Not to mention, long-duration, steady-state workouts tend to make you feel ravenous afterward. Helllllooooo, post-workout “carb loading” with a giant bowl of pasta and two glasses of wine. Those extra calories more than negate what you’ve just burned at the gym.
Worse still, MISS workouts are a recipe for overtraining and repetitive motion injuries. According to the USF Sports Medicine & Athletic Related Trauma Institute, 65% of runners will sustain an injury during one year of running, and a whopping 50% of those injuries will be recurrent! (2)
That means that running is about 10 times more dangerous than weightlifting, leading to 1 injury in every 100 hours spent running, compared to 1 injury per 1,000 weight training hours.
For weight loss, cut down on the MISS or mix it up with the revolutionary new concept below.
Low-Intensity Steady State Cardio
In our earlier example of why a 20-minute HIIT run isn’t possible, we also talked about the aerobic energy system. This bad boy will keep you moving for hours as long as you keep it low-intensity. Since you can sustain a walking pace basically forever, you’re not limited in any way, shape, or form to how much LISS cardio you can do.
Okay, maybe you’re limited by the hours in your busy day, but adding a long walk to your routine a couple times each week can increase your calorie burn with relatively little risk of overtraining or injury. And taking a long walk is damn enjoyable compared to suffering on the treadmill.
The Benefits of Interval Training
Interval training (whatever variety you choose to practice) allows you to perform more intensely and increase your training volume in less time than traditional steady state cardio. It’s more time-effective and can produce similar results to longer duration steady cardio sessions.
Interval training has been scientifically proven to increase your work capacity, increase your VO2 Max (a measure of how intensely you can push yourself), and to improve your insulin sensitivity, which allows you to better metabolize carbohydrates for energy. (3)
Don’t forget the “fun factor.” Interval training is way more interesting than steady state cardio. You can mix up different exercises, from body weight to barbells, kettlebells to ropes and slam balls. This makes interval workouts a heck of a lot more fun than running on the treadmill. The “fun factor” will keep you coming back to the gym long after the New Years Resolution crowd has given up on the hamster wheel.
What about EPOC?
A lot of fuss has been made that HIIT training causes Excess Post-Exercise Oxygen Consumption (EPOC) or the “after burn” effect. While it’s true that intervals – and resistance training, too – can boost your metabolism for hours after your workout, the effects may be overly exaggerated.
According to Knab, et al, EPOC only generates slightly more energy expenditure in addition to the calories burned during exercise. For example, in a study of male athletes performing 45-minutes of vigorous cycling, their calorie expenditure during the workout was +/- 519 kcal. Their “after burn” added an additional 190 kcal over the next 14 hours. So, yes, HIIT training does boost your metabolism after your workout, but you would have to perform 45-minutes of vigorous (read: “hard”) exercise about 3x per week to achieve about 8.5-lbs of weight loss over the course of one year. (4)
If you want to check my math on that, here ya go:
3 workouts per week X 52 weeks per year X 190 cal = 29,640 cal burned through EPOC
Assuming 3,500 cal per pound of body fat, that’s 29,640/3,500 = 8.46 pounds
Yeah, EPOC is great, and all, but you would have to religiously complete three hard cardio workouts per week for an entire year in order to lose just eight and a half measly pounds. I’m not saying that interval training is a waste of your time, but if you have significant amounts of weight to lose, you must couple your cardio efforts with resistance training and a diet that creates a calorie deficit.
The Final Word
Given all the information we’ve addressed above, we’re left with the burning question: what kind of cardio should you do if you want to lose weight and burn off body fat to reveal a lean, sculpted body?
My final answer is all of the above.
Each type of cardio has its pros and cons. Interval training is great because it is time efficient. You can build up to 2-3 HIIT sprint workouts per week or 2-3 HVIT or VIIT workouts per week. But you can’t do HIIT alone because it taxes your body’s ability to recover. Add 1-2 days of MISS or LISS cardio, and you have a solid five-day per week cardio training plan.
But for the most “bang!” for your training buck, you should without a doubt incorporate resistance training (ie, weightlifting) into your weight loss training plan. Resistance training sends the signal to your body to hold onto lean muscle tissue. If you simply do cardio, you’ll end up looking what the kids are calling “skinny fat” instead of lean and sculpted.
More importantly than the cardio vs weights debate, no matter how hard you train with intervals and weights, the only way you will you ever begin to lose weight is by following a diet that creates a caloric deficit.
Combine all three – cardio, weights, and a calorie deficit – to create the fat-loss trifecta.
(1) National Academy of Sports Medicine. “HIIT, HVIT, Or VIIT: Which IT Are You Doing, And Do You Know The Differences?” http://blog.nasm.org/sports-performance/hiit-hvit-viit-know-differences/
(3) Men’s Journal. “7 Scientifically Proven Benefits Of Interval Workouts.” https://www.mensjournal.com/health-fitness/7-scientifically-proven-benefits-interval-workouts/2-youaere-more-likely-to-stick-to-it/
(4) Knab AM, Shanely A, Corbin KD, Jin F, Sha W, and Neiman DC, (2011). A 45-minute vigorous exercise bout increases metabolic rate for 14 hours. Medicine and Science in Sports and Exercise, 43:1643 – 1648.