If you want to change your body and boost your metabolism, you need to exercise with intensity.

Luckily, the more intensely you go, the less exercise you need.

If you exercise for too long at too low an intensity, your body starts breaking down your muscles to make fuel.  What is long, low intensity exercise?

Cardio.

The way most people do cardio is to exercise in their “fat burning zone” for as long as possible, with the idea that longer is better.

But done too long or too often, wasting of your muscles will occur.

Muscles are what give you a higher quality of life, power your athletic movements, shape your body, and rev up your metabolism.

Destroy your muscles with cardio and you lose all those benefits. (Check out these posts for why you need muscle: Get Some Firmness On Your Frame and You Need Muscle To Lose Fat)

Traditional cardio training doesn’t have enough intensity to to change your metabolism – yet is usually done in high enough volumes to cause large amounts of muscle tissue destruction.

“Cardio” doesn’t work for fat loss and changing your body… And it may cause you to lose the most productive and protective tissue in your body.

If you insist on doing regular cardio, make sure you have heavy resistance training sessions to convince your body to hold onto its precious muscle.  And do as little cardio as possible all the same.

Well, if you can’t do cardio to lose weight, what CAN you do?

Exercise below that cardio threshold.  Easy walks, mellow bike rides, relaxing hikes.  These aren’t intense enough to cause you to start breaking down muscle tissue, they still burn calories, and they encourage recovery from higher intensity training.  Not a lot of metabolic changes from this type of exercise, but it’s fun, easy, and helps.  So go for a stroll, dang it!

Use interval training.  High efforts interspersed with low efforts have beaten traditional cardio in the three most important arenas: research has proven intervals are better, experience has shown intervals to be better, and intervals are just plain more fun.  There’s tons of info on interval training on this site.  (If you want to get started now, peep this: Beginner Interval Workouts)

Use circuit training.  Best of both worlds.  You get to do resistance exercises in a series fashion to ramp up your metabolism and calorie burn while building toned muscle.

Fix your nutrition.  If your food and resistance training is spot on, you probably won’t even need to to either type of “cardio” – easy or intervals – to get lean.  The right nutrition plan will balance your hormones, ramp your metabolism, and lead to fat loss.  All without beating yourself up in running shoes.