There seems to be a belief which is a very common one. That belief is that performing cardio will prevent muscle growth and even cause the body to burn muscle to use as energy, therefore reducing muscle mass. This is known as being in a catabolic state.
It’s true that prolonged exercise whether it be weight training or cardio can trigger the body into a catabolic state where the body needs to break down muscle tissue to use as an energy source. However the key word in that sentence is “prolonged” exercise not just cardio exercise but any exercise. Cardio is generally more energy hungry than weight training so cardio is more likely to trigger the body into using your muscle as energy(going catabolic).
The actual risk of your body burning off your muscle by performing cardio is exaggerated and it has become somewhat a workout myth and misconception.
Yes it can happen if your cardio is intensive and long. Your body needs energy and it has to get it from somewhere and your body will break down your muscle if it needs to. However this will only cause an issue if your cardio or exercise is intensive and prolonged, for example running a Marathon. Running for 10 or 20 minutes on a treadmill or playing a sport will make no difference.
What you eat matters!
Exercise is not the only factor, your diet plays a major role in whether your body goes into a muscle burning catabolic state. If you don’t eat enough or give your body the nutrients it needs it will contribute to a catabolic state.
To help avoid muscle loss during exercise make sure that you eat regularly throughout the day. Provide your body with the nutrients and energy it needs and it will not need to feast upon your muscles.
Diet tips to avoid catabolic states
Eat a couple of hours before your workout, you body will use the energy it gets from your pre workout meal so it will not require breaking down your muscle mass.
Eat breakfast! while sleeping your body will go without food for around 6 – 9 hours and your body uses up energy and nutrients from your last meal while you are sleeping. So you need a fresh intake of nutrients and energy when you awake.
Sport drinks are generally not that good but they provide instant energy for your body which can prevent that catabolic state during your workouts.
This is the state that most weight trainers are trying to achieve. An anabolic state is when your muscles are repairing themselves in a way that makes them bigger and stronger. When you train it’s like a tug of war between the anabolic and catabolic states. To stay in that anabolic state you need to train hard to break down those muscle fibres and then provide your body with the nutrients and energy it needs to repair and grow, or in other words eat well before and after your workouts.
Cardio can benefit muscle building
Cardiovascular fitness can actually aid muscle growth. Cardio fitness aids with heart and lung capacity, blood circulation and general fitness, all of these benefits will aid with muscle development.
The bottom line
As long as you eat well and don’t overdo it with the cardio, cardio will actually improve your anabolic muscle building ability.