Well, let’s look at the typical options. Running, biking, swimming, elliptical, rowing, walking, stair climbing/stair master, upper body ergometer, and obviously many outdoor sports such as cross-country skiing.

So there are many forms of cardio to choose from and they all work. It’s important to always remember that. All forms of exercise will work in the long run given the right training program and consistent effort.

But we’re interested in not only what works but works what best for burning fat! We want to get the best bang for our buck, right?

Since the goal is to maximize oxygen consumption (and thus VO2) it is essential to find activities that will recruit the greatest amount of muscle. This is because the more muscle that is needed to perform an activity or movement, the more oxygen that will be needed to supply those working muscles. Make sense?

Oxygen is the precursor to all the energy your body produces. Your working muscles need oxygen otherwise they will quickly fatigue and will be unable to perform their functions.

It is well known that athletes in sports that require large amounts of muscle have the highest VO2 max (maximum aerobic capacity) because their sports demand a massive supply of oxygen to their working muscles. As such, the highest VO2 max on record exist not in runners (as many would think) but rather cross-country skiers and rowers.

Think about that for a second. Both cross-country skiing and rowing involve just about muscle in the body working against resistance. Both the upper body and lower body muscles are pushing and pulling a given resistance which makes these sports not only great aerobic training tools but also fantastic fat burning cardio machines.

If you’ve ever watched Olympic rowing you will have undoubtedly noticed towering men and women stacked with large and lean muscles. Most of the male rowers are upwards of 6’4’’ and 220 lbs of shear muscle, making them calorie-burning machines.

These male and female rowers can get away with their large frames because rowing is not a true weight-bearing sport. In fact, this terrific sport idealizes large muscular athletes because they can produce a lot of power, both aerobically and muscularly, through their large muscle mass.

However, If you took these same rowers and asked them to run at the same intensities at which they row, they would most likely have a difficult time – not only because of the specific nature of running but also because they would be “carrying” a lot of mass.

How many 6’4”, 220 lbs runners do you know of? Most runners are slim and slight. It simply makes their movement much easier. Less weight to carry means less effort. If you have a tough time envisioning this, then I encourage you to go for a run with a 20 lbs pack on your torso. You will immediately notice the difference.

Similarly, most cross-skiers don’t exhibit the same physical stature as rowers. However, their aerobic capacity is astronomical. Yet, they are more similar to runners in physical stature as cross-country skiing is a weight-bearing sport and thus does not reward athletes with lots of weight, even if it’s muscle.

Energy Expenditure (Calorie Burn) in Various Activities

Activity (per 1 hour) 130 lbs155 lbs190 lbs

Cycling, 10-12 mph 354 422 518

Cycling, 12-14 mph 472 563 690

Running, 5 mph 472 563 690

Running, 7 mph 679 809 992

X-Country Skiing, > 8mph 826 985 1208

Walking, 3 mph 207 246 302

Rowing, vigorous effort 561 669 819

As you can see from the above chart, running burns more calories than other activities, at the same intensity. It is therefore the most effective type of cardio for burning fat and helping you lose weight.

There are two main reasons for this.

First, running is weight bearing which means that the muscles of your lower body must work harder to support you and propel you forward; thus, expending more calories. Therefore, the heavier you are, the more calories you will burn (assuming equal intensity as someone who is lighter).

Second, running is one of the least efficient of human movements, which means that it produces a lot of heat/energy expenditure for its movement. This also means that a lot of calories are being spent. This is great for those who want to lose weight but not so great for those looking for efficient modes of movement.

But it makes sense if you think about it. Cycling is easier than running, right? That’s because cycling is one of the most mechanically efficient human movements, meaning that more of the energy you put into the movement actually results in movement (and not as much heat production as running!)