Is Cardio Really the Secret to Fat Loss

One of the most talked about subjects in the fitness industry is this: Cardio and fat loss.

Here’s what your clients (and yes, even us trainers too) want to know:

Is cardio really necessary for fat loss?

Which type of cardio will optimize fat loss? LISS (low intensity steady state cardio) or HIIT (high intensity interval training)?

The good news is that there is some pretty clear research that can answer these questions. First, let’s take a look at what cardio actually is and what the different types do for your body.

Aerobic vs. Anaerobic Training

There are two basic types of physical training: aerobic and anaerobic. To understand how our bodies lose fat during training, and to be better able to explain it to your clients, you need to know what these terms really mean, technically and practically.

Aerobic vs Anaerobic Exercise

Aerobic activity. Aerobic training requires the presence of oxygen. It is the type of activity that primarily works type I muscle fibers. This helps to increase muscle endurance and capillary size, and generally helps the heart muscle to pump blood more efficiently. Aerobic activity is done at a pace you can sustain for an extended period of time; think 50 to 70 percent of VO2max and a heart rate between 120 and 150 BPM: lower intensity jogging, swimming, or biking, for example.

Anaerobic activity. This is just the opposite of aerobic activity. Anaerobic training is exercise that does not require the presence of oxygen. It works the type II muscle fibers, which leads to greater size and strength of muscles. Sprinting until you gas out or resistance training with heavy weights is anaerobic. When you work at 90, to well over 100 percent of your VO2 max performing anaerobic activity, oxygen builds up, lactic acid builds up, and you start to feel the burn.1 You can’t sustain this kind of activity for extended time periods like you can with aerobic exercise.