What Burns More Calories: Cardio, Intervals, or Weight Training?

By Steve Kamb

Fat loss is at the front of everybody’s mind these days, even storm troopers.

Let’s say you want to lose weight, and you want to do so in the fastest way possible.  Is it hours on the treadmill?  Sprints up a hill?  Could it possibly be squats and bench presses?  I’m going to guess that you have assumptions on what might be best for you.  In today’s royal rumble, I’m going to break down the difference between these three contenders and let you know which will give you the most bang for your buck.  The results, which certainly aren’t unanimous, will surprise you…

Meet today’s contestants:

• Cardio: Pretty much anything with relative low intensity that you can do for a prolonged period of time that elevates your heart rate.  Regular aerobics, going for a three mile jog, running on a treadmill for an hour, using the elliptical for twenty minutes, etc.
• Interval Training: When you decide to run, bike, use the elliptical, etc. with varying rates of speed and intensity.  Sprinting for 30 seconds followed by 90 seconds of jogging, and repeating this cycle for 20-30 minutes.
• Weight Training: Whenever you lift weights or do body weight exercises, often times in a cyclical nature.

There have been hundreds and hundreds of studies done on this stuff (yay for science), and it’s certainly something that I’ve put considerable time into researching as well as it’s my job to figure out how to get in shape most efficiently.  I will have a decision for you by the end of the battle.  However, before we get there, there’s ONE thing that needs to be made crystal-clear:

If you are interested in getting in shape, the MOST important thing you can do for yourself is adjusting your diet.

Your diet is responsible for 80-90% of your successes or failures.  As I’ve said previously, even if you spend ten hours a week exercising, that still leaves 168 hours for you to mess things up.  Doh.  If all you care about is losing weight, thefastest path to success is with a freaking kick-ass diet.  Keep your total number of calories under control, cut out the junk food, give up soda, and start eating REAL FOODS: veggies, fruits, and lean meats.

Got it? Good.

So you’re on board with the whole “eating right” thing (w00t), but you still want to exercise to burn more fat.  Let’s break down each competitor:

Cardio

Cardio is the most basic thing you can do when it comes to burning calories.Let’s talk science: if you burn more calories than you consume in a day, you willlose weight.  Step on a treadmill, run three miles, and you’ll burn around 300 calories.  You don’t need any special weights, have extensive knowledge of any difficult exercises, just a pair of shoes (or a pair of Vibrams) and your legs.  This is why the majority of people who start exercising do so by just running a treadmill or elliptical for hours: it’s tough to mess up, and it’s pretty mindless.

Now, here’s my problem with cardio: it can be really boring!  Running outside is a different story, but I’d rather punch myself in the crotch than spend two hours on a treadmill.  Secondly, in terms of getting in shape, it’s definitely not the most efficient form of exercise.  Lastly, although it trains your heart to be in shape by remaining at a higher level of operation while exercising, it doesn’t train your heart to prepare for moments of extreme stress because it never really has to deal with rapid changes (explained in the next section).

So why isn’t cardio efficient when it comes to burning calories? There’s very little Exercise Post Oxygen Consumption (EPOC) with cardio, which means you only burn calories when running; not much happens afterwards.  If you want to read about how cardio doesn’t really burn any extra calories, you can read thisfascinating article from NYT which is loaded with studies and references on the subject at hand.

What IS good about cardio? The thing about cardio that makes it better for almost everybody, other than it’s easy learning curve, is that it’s very low impact – your body can go for hours and hours, day after day, and not get worn out.  If you have the desire and willpower, you can burn calories all day long, like the guys inBorn to Run.

High-Intensity Interval Training

When it comes to efficiency in burning calories, high-intensity training is leaps and bounds ahead of cardio.  Why is that?  EPOC, dude, EPOC!  That stuff I was talking about before.  Essentially, when you do high-intensity interval training (HIIT), your body and metabolism function at a higher rate of burned calories for hours and hours afterwards.  What does that mean? It means you’re burning calories while sitting on your ass playing Modern Warfare 2 or re-watching Lost Season 5 (not that I’m doing this currently, or anything like that).  You can read all about HIIT here.

So, how the hell does that work exactly?

HIIT constantly forces your heart to adjust to changing conditions: sprints, jogging, sprints, jogging, up hills, down hills, etc.  Your heart learns to operate outside of its norm, and your body learns to adapt to these changes.  All of this changing and sprinting kicks your metabolism into high gear for hours after you finish exercising.  To quote Mark’s Daily Apple, a site that I love:

A study (PDF) from the University of New South Wales followed the fitness and body composition changes in 45 overweight women in a 15-week period. The women were divided into two groups and assigned interval or continuous cycling routines. The interval “sprint” cycling group performed twenty minutes of exercise, which repeated eight seconds of “all out” cycling and then twelve seconds of light exercise. The continuous group exercised for 40 minutes at a consistent rate. At the end of the study, the women in the interval group had lost three times the body fat as the women in the continuous exercise group. (An interesting note: the interval group’s loss in body fat came mostly from the legs and buttocks area.)

Three times the amount of fat loss and half of the exercise time? Sounds good to me.  If you sift through the rest of Mark’s article, you’ll find reference after reference discussing the benefits of varying your speed and intensity over straight normal cardio.  Now, the bad thing about HIIT is that it takes your body quite a bit of time to recover, and you can really only do it for 20-30 minutes at a time before you get too exhausted to continue.  The other bad thing about HIIT?  Your body will hate you after just 20 minutes.

Weight Training

So if cardio is decent for burning calories while you exercise, and high intensity interval training is more effective because it burns calories both during and after exercise, where does weight training come in?  Alwyn Cosgrove, a fitness expert whose opinion I highly respect, wrote a great article discussing the Hierarchy of Weight Loss loaded with numerous studies highlighting the benefits of weight training in comparison to cardio.  This is the best part:

Overweight subjects were assigned to three groups: diet-only, diet plus aerobics, diet plus aerobics plus weights. The diet group lost 14.6 pounds of fat in 12 weeks. The aerobic group lost only one more pound (15.6 pounds) than the diet group (training was three times a week starting at 30 minutes and progressing to 50 minutes over the 12 weeks).

The weight training group lost 21.1 pounds of fat (44% and 35% more than diet and aerobic only groups respectively). Basically, the addition of aerobic training didn’t result in any real world significant fat loss over dieting alone.

Thirty-six sessions of up to 50 minutes is a lot of work for one additional pound of fat loss. However, the addition of resistance training greatly accelerated fat loss results.

These are the lessons I’d take from this: what you eat is the most important thing when it comes to weight loss, aerobic training helps but not nearly as much as you’d think, and weight training when combined with the two is the most effective method to dropping pounds.

Now, what kind of exercises are best suited for this type of weight training for weight loss?  According to Alwyn, exercises that recruit the largest number of muscles (squats, lunges, kettlebell swings, squat thrusts, burpees, inverted rows, pull ups, and push ups).  Do any of these exercises sound familiar? (cough, NF beginner body weight workout and NF advanced body weight workout, cough).  By doing these exercises in a circuit without stopping, keeping your rep ranges in the 8-12 range, your body will get a super workout, you will build muscle, and you’ll burn calories at an accelerated rate for reportedly up to 38 HOURS after your exercise.

Want some more literature about how weight lifting is better than intervals (and way better than cardio)? Check out Alwyn’s interview on the Death of Intervals over on Jason Ferruggia’s site.  When it comes to performance, these fitness guys are two of the best in the business: no bull****, just results.

Is it that cut and dry?

Nope. Sure, if you keep the variable time as a constant, like 30 minutes of exercise, doing “metabolic resistance training” (a fancy term for weight lifting circuits) burns more calories than high intensity interval training, which burns more calories than straight cardio.  However, due to the stressful nature of Weight Training and HIIT, you can really only do those activities for 30-45 minutes before your body gives up and needs a few days to recover.  Cardio doesn’t have as nearly as stressful an impact on your body, so you can go for hours and hours and hours and do it again the next day (provided your body is in shape).

Medhi over Stronglifts highlights this uber-important fact in a great post calledWhy HIIT Is NOT Better For Fat Loss.  Essentially, because you can only do so much HIIT or weight training, you can only burn so many calories before your body wears out.  If time isn’t a factor for you, and you don’t mind spending more time in the gym on a daily basis, you can burn way more calories doing steady cardio than with just 30 minutes of weight training three days a week.

Judge’s Verdict

My decision on what you should do certainly depends on your fitness level, how much time you can devote to exercise daily, and what you actually LIKE to do. Remember: above all else, your diet is king.  Eat poorly and none of the above matters.  Eat right, eat real foods, and exercise, and you’ll get better.  Here is my advice to you:

Do cardio if:

• You really enjoy the treadmill or elliptical, or you just really like running
• You have all the time in the world
• You’re just getting started and don’t really know what you’re doing

Do HIIT if:

• You don’t like lifting weights, but you still want to burn calories as quickly as possible
• You only have a limited amount of time every day
• You like pushing your body to its limits.

Do circuit weight training if:

• You want to build muscle while burning calories
• You like burning calories while sitting on your butt.
• You’re not afraid of lifting weights.

Honestly though, this is just the science-y stuff.  Ultimately, I just want you to be happy and healthy, which means it’s up to you to find a great combination of the three methods above that keep you smiling and keep the weight off consistently.  Luckily, there’s no 100% perfect way to get in shape, so find something that you love and stick with it.  If it ain’t workin for ya, take some advice from this post and see what kind of results you get.

If you’ve spent months doing steady-cardio, try varying the speeds and intensity every once and a while.  If you’re afraid of lifting weights, give it a shot once or twice a week and see if the weight starts to come off quicker.  Try adding some basic cardio into your weight lifting routine on off days to knock off a few more calories.  Most importantly, eat better!