Almost everyone, at one time or another, has wanted to “lose weight” and felt that the best way to do so was to hop on a treadmill, or another cardio machine, and go for as long as they can. Burning more calories equals losing more weight, right? No, not necessarily.

There are many reasons why this thought process is a dangerous one to have. Let’s take a look at a few of those reasons.

Excessive Cardio = Muscle Loss

An excessive amount of cardio results in lower hormone production. This leads to more fat gain and raises cortisol levels, i.e. the stress hormone. This is not a positive. Lower hormone production combined with less available calories to fuel your body, due to cardio, results in muscle growth stagnation or an actual LOSS of muscle mass.

I Burn More Calories Doing Cardio Over Strength Training, Right?

Yes, the machine will tell you that you burned a large number of calories holding on for dear life on a treadmill, set to an 18% incline, for an hour. However, that’s where the calorie burn stops.

Strength training raises the metabolic rate, the “after-burn” effect, for longer periods of time than what aerobic work does – up to 48 hours. Most fat oxidation occurs between training sessions, not during. As such, your exercise sessions should primarily be geared toward building muscle and boosting the metabolism, not “burning fat.”

A study found that Exercise Post Oxygen Consumption (metabolism) was elevated significantly for 38 hours post-strength workout. That’s a significant timeframe for metabolism to be elevated. If you trained for one hour on Monday morning, you’d still be burning more calories, without training, at midnight on Tuesday.

Doesn’t Cardio Burn Fat?

The body burns predominantly fat during aerobic work, yes. However, as a result, the body adapts by up-regulating the enzymes that store body fat.

Read that again. Now let’s rephrase it. Your body adapts to cardio by making it EASIER to store fat!

The body burns predominantly glucose/glycogen during strength training. As a result, the body adapts by up-regulating the enzymes that store muscle glycogen, otherwise known as carbohydrates. Strength training has more powerful, positive nutrient partitioning effects than cardio. This means that nutrients are diverted more towards muscle cells, where they can be used to build or maintain lean muscle tissue, and away from fat cells, where they can be stored.

What Should I Take Away From This?

With long steady-state cardio, the body makes it easier to create and store fat and harder to build muscle. With strength training, a higher utilization of carbs and an increase in muscle mass help lower your body fat percentage.