Cardio: To do or not to do... And how much!

First, a question: What does cardio look like?  It has many forms, but the basic idea is that it's exercise that elevates the heart rate and uses oxygen as its primary energy source.  It can look like many things - swimming, running, walking - but it may not be what you're looking for.
 
Before you head to the gym to "get your cardio in," you should ask yourself a few questions: What is my goal? And, most importantly:  Is cardio really the best way to get to my goal? Assuming that you are like most fitness enthusiasts, you're probably in it to lose a few pounds or "tone" your body (same, same).  Another group of gym-goers may be preparing for their upcoming sports season. And, finally, your goal may be to run the Cherry Blossom 10-miler in April...  In this post, I'm really focusing on the first two. 
 
The people in those two groups may just be wasting their time. And, really, let's be honest, time is not something you like to waste in the gym. Today we're really going to focus on those looking to lose weight.
 
This subject has come up multiple times over the last week, and I wanted to get some thoughts out there. Well, my thoughts supported by those from our industry's leaders. A large part of what I use in this post is taken from Alwyn Cosgrove's "The Hierarchy of Fat Loss."
 
So, since you're asking, what is Alwyn's Hierarchy of Fat Loss?
 
1. Correct Nutrition
"You absolutely cannot out-train a crappy diet."
2. Activities that burn calories, maintain muscle mass, and elevate metabolism
The bulk of our calories burned come from our resting metabolic rate, and this is determined by muscle mass and how hard it's working.  We need to maintain or gain muscle mass if we are to lose fat.
The smallest part of total calories burned comes from calories outside of our resting metabolism.
3. Activities that burn calories and elevate metabolism
This is that EPOC stuff that we've been talking about.  Exercise Post Oxygen Consumption is defined scientifically as the "recovery of metabolic rate back to pre-exercise levels" and "can require several minutes for light exercise and several hours for hard intervals."  These are calories burned due to an increase in demand from our body after an exercise session.
4. Activities that burn calories but don't necessarily maintain muscle or elevate metabolism
This is the least effective tool.  In most people's vocab, this is simply referred to as "cardio."
 
Now, before you give me any credit, just remember that I am paraphrasing Alwyn here... I don't want anyone to claim that I'm stealing! Now, for the meat and potatoes part... (To keep this from getting too bogged down, I'm going to remove the studies from the work... I'll link to the full article at the bottom)
 
Five Factors for Fat Loss Training
 
1. Metabolic Resistance Training
Resistance training is vital to fat loss. This means work every muscle group hard, frequently, and with an intensity that creates what Alwyn calls "afterburn" that leaves the metabolism elevated for several hours post-workout.
Metabolic resistance training can be barbell complexes, kettlebell work, supersets, and/or tri-sets.
2. High Intensity Anaerobic Interval Training (HIIT)
 It burns more calories than steady state and elevates metabolism significantly more than other forms of cardio. The downside is that it flat-out sucks to do it! One reason this works so much better than steady state is due to the awesome power of the human body (9 times better in the study Alwyn quotes!).  When you jog on the treadmill every day your body easily adapts to the stress.  If you tear yourself a new one with anaerobic intervals beyond the aerobic threshold, your body will not adapt and you will burn fat.
These intervals are more intense than any aerobic interval.  Anaerobic intervals are done beyond the aerobic threshold, where your body can no longer just use oxygen for its energy. These intervals are done in a perceived rate of exertion of 9-10 on a scale to 10.
“Interval training is like putting your savings into a high return investment account. Low intensity aerobics is like hiding it under your mattress. Both will work, but the return you get is radically different.”
3. High Intensity Aerobic Interval Training
Still within the aerobic threshold (a perceived rate of exertion of 7-8 on a scale to 10), but with a higher intensity.
4. Steady State High Intensity Aerobic Training
Just hard cardio (don't see this much...). 
5. Steady State Low Intensity Aerobic Training
Moving more.... Walking to get your groceries or taking the stairs instead of the elevator are pretty common options.
 
From here Alywn gets into what I heard Mike Boyle call the 180 degree principle. “If you see most of the people in the gym doing something you should do the opposite.”

As I mentioned in my “Cardio Zombie” (As Kirk not-so-fondly refers to them) post, anybody working out at a commercial gym will see lines upon lines of full treadmills. According to Boyle we should walk the other way. Alwyn prescribes metabolic resistance training as his first attack against the bulge. This battle begins with time management.

That time should be allotted according to the following:
Time Available - Training Used
≤ 3 hours - Metabolic Resistance Training
3-5 hours - Add High Intensity Anaerobic Intervals
5-6 hours - Add High Intensity Aerobic Intervals
6-8 hours - Add Steady State High Intensity Aerobic
> 8 hours - Add Steady State Low Intensity Aerobic

With fat loss training the key is to do the maximum amount possible while maintaining our recovery levels. As you see in the chart, the intensity diminishes as we spend more time in the gym. Our body can recover much better from the steady state aerobic work than it can from the resistance training, so once additional time becomes available for burning calories we can effectively use it for fat loss without inhibiting our recovery.

Special thanks to Alwyn Cosgrove for the inspiration this week. I know his work here has helped many coaches and trainers understand the science of fat loss. You can find the original article here.