Good Cardio – Bad Cardio?

Most people think of cardio as jumping on a treadmill, elliptical, or exercise bike, getting your heart rate up to 80-85% of what’s appropriate for your age and keeping it there for 20 to 30 minutes before cooling down. The inherit wisdom is that this is a good thing and will strengthen your heart and help you burn fat.

What’s wrong with that?

Nothing, besides the fact that studies show:

  • The long repetitive movement is bad for your joints
  • It literally reduces the size of your heart, lungs and muscles over time
  • You put stress on your heart similar to that during a heart attack
  • It trains your body to hold on to the fat and sacrifices lean muscle tissue
  • And if you persist through middle age it starts robbing your body of testosterone and growth hormone while raising cortisol to levels which have a degenerative effect on your bones, muscles and internal organs

So why does this happen?

When you exercise at moderate intensity for 45 min. or longer, your body is burning 40% carbohydrates and 55% fat. When you exercise at a HIGHER intensity for short intervals of a minute or two at a time, your body burns 95% carbohydrates and 3% fat. So logic would tell you that you want to go with the moderate intensity for a longer period time because you’ll burn more fat. Right?


Here’s what actually happens and yes it defies logic.

When you exercise for long periods of time, (45 min. or longer) your brain sends a message to your body to hold on to the fat it just burned after you’re done exercising. This is because your body feels stress and threatened. The body’s natural response is to replace the fat it just burned, in preparation for the next time this happens. If this doesn’t happen by eating, your body will scrape it from your muscle tissue and organs.

If you go back to pre-agrarian times, our ancient ancestors hunted for their food. That required them to stalk and run after their prey until they could get close enough to chuck a spear into it. Naturally the animals were fast so the hunter could only run after them for a short time. If they missed their critter, they had to repeat what they just did after a short rest because they didn’t want to let their food get too far down yonder.

This type of activity made for a very muscular body with a strong heart and lung capacity. It’s also inscribed in the DNA of our brain and body to this day.

Think of the body of a sprinter compared to a long distance runner. The sprinter is very chiseled, with long, lean and rounded muscles. They never run long distances to build cardio to train for their sprints or to lose weight.

On the other hand, the long distance runner typically has a very frail appearance. Their chest and shoulders look gaunt and emaciated.

That’s because in order for them to compete in long endurance events, their heart, lungs and internal organs have shrunk so they can provide the capacity to go longer distances.

Think of it in terms of automobiles. How did we make cars get better gas mileage? We made the motor and the car smaller. Now they can go longer distances without having to fill up as often but they lack the power they used to have.

The problem with that is you rob your heart of its reserve capacity. That’s why you see people falling over dead in marathons and triathlons. Their heart has grown so small and weak that it lacks the ability (reserve capacity) to defend against attack.

If you’re an endurance athlete there’s not much you can do avoid these things other than quit the sport. In order for your heart and lungs to be able to “endure” they have to grow smaller in order to carry the load further.

If you just want to burn fat, I recommend interval training for no longer than 15 minutes. Exercise at a high intensity for a minute at a time and take a two minute rest between sets. You want to bring your heart rate back down between sets. Five sets with two minutes in between will get you to 15 minutes.

When you’re just starting out – you may want to only do 30 seconds of exercise and rest for 3 or 4 minutes in between sets until you progress.

Remember what I said previously about this type of exercise burning 95% carbohydrates and 3% fat (during exercise)?

What happens is… your brain sends a message to your body to get rid of the excess fat because it doesn’t need it. You never move into your fat burning zone during exercise so your brain senses it doesn’t need the fat and flushes it.

Here’s a little secret!

Your body burns 60% fat while just resting!

So do short, high intensity, bouts of exercise for 15 minutes and you’ll see that you’ll burn fat like never before.

Not only that! You’ll:

  • Build a stronger heart and lungs
  • Have the capacity to avoid heart attacks
  • Build a disease resistant immune system because of your increased lung capacity
  • Increase your energy levels

So exercise less, build a stronger heart… and burn more fat.