So one of the biggest questions that any trainer gets from his/her client base is “How much cardio should I do?”  Now the answer that I am going to give is a little bit counter to common accepted knowledge.  I would argue that this is a case where definitely less is more.  For example, traditional thought process says that if you want to lose weight and burn fat that you have to do at least 30-45 minutes of low-intensity cardio 4-5 days per week?  Outside of the fact that that just becomes a HUGE time commitment (especially if you are doing other training), I would argue that I could get more benefit out of less time.  Now, let’s be straight.  If you are going to be shorter in your duration of workout, you are going to have to work harder, no doubt about it.  So, if you are averse to hard work, then by all means, stay the less effective course.  But look at it this way.  You could work (walk/jog) on a treadmill at 70% of your max (7 on a scale of 1-10) and burn “X” amount of calories.  But if you work harder for a shorter amount of time, couldn’t you burn the same amount of calories in a lesser time-span?  Of course you could.  Let’s take an example and bear this out. 

Routine #1 – 30 minutes slow and steady (60% max)

     Total calories – 146/Fat calories 73 (50%)

Routine #2 – 30 minutes intervals (alternate work/rest) at 85% max

     Total calories – 206/Fat calories 82 (40%)

Now, what we have always been told is that you should work at a lower rate in order to burn fat and not carbs, right?  And in traditional logic that would be true, wouldn’t it, since at the lower intensity we burned a higher RATE of fat (50% to 40%).  But isn’t the ability to lose weight the difference between calories intaken and calories burned ( a little over-simplified, I know, but we’ll go with it for now)? And where did we burn more calories?  In example #2.  Put this in there, as well, that even though fat calories were burned at a lower rate, where were more fat calories burned overall?  Example #2.  Now what makes more sense?  I’ll actually throw 2 more factors at you that make it even better (we’re just full of sunshine today, right?).  Factor #1 – Long, slow, distance training (cardio), by nature is catabolic.  That means that it breaks down body tissue.  Fat tissue, yes, but muscle as well.  I’ll ask you, when was the last time you saw a “buff” marathoner?  Interval training, however, since it is higher intensity is not catabolic in nature.  So, whereas you will burn fat tissue, you will not break down muscle, since you are working at a much higher rate for shorter bursts of time.  Therefore, you will both burn fat AND build lean muscle tissue.  Isn’t that the best of both worlds?  Factor #2 – Everyone knows that one of the many benefits of exercise is that it keeps your metabolism elevated for a time after your workout is over.  So you’re getting benefit not only from the workout itself, but after, as well.  Well recent studies show that anaerobic interval training can keep the metabolism elevated up to 4-5 times as long as typical aerobic exercise.  Some studies say in excess of 8-9 hours.  Picture working out at breakfast and still reaping the benefits at dinner time.  Now how cool is that?  Something that you SURE do NOT get from traditional cardio.  Now, am I saying that cardio is the devil?  No, I’m not.  It has it’s place.  Just mainly as a recovery mechanism.  You’re body can’t work that super hard more than 2 or 3 days in a row.  All I’m saying is that instead of your standard 45 minutes on the elliptical, shorten….Do 20 minutes alternating between a minute all out sprint and a minute of super easy rest.  Do quarter mile (.25 treadmill) repeaters.  The bottom line is that the harder your body works, the more benefits are reaped.  So why cheat yourself?  Get the best out of everything that you do.  Be good!