Updated: May 16, 2020
There is always conflicting advice about how much cardio to do, in particular if you are more focused on strength training. Many worry that cardio will affect muscular gains, so read on!
Your body adapts to healthy changes from cardio training. Starting with the lungs, unlike muscles, lungs do not get bigger with exercise. Instead, the body uses more of the lung tissue that is already there. Taking in more oxygen to utilise more oxygen creating a more efficient respiratory system lowering blood pressure.
Other words, less 'gasping for air'.
In reality, cardio needs to be done regularly and enhances musculature. Here is why.
The heart gets stronger, in particular the left ventricle increases in volume so a greater volume of oxygenated blood is pumped around the body. Your muscles benefit from this, and this is a natural action. You breathe easier and more efficiently.
Muscle tissue benefits from freshly oxygenated blood to the working area.
Your skeletal structure gets stronger by the constant pulling effects of muscle on bone, encouraging osteoblasts to lay down new bone. This is the natural function of bone. Ligaments and tendons get stronger. Joint stability improves.
(Please note that cardio such as swimming and cycling are NOT as effective as these are non-weight bearing). You need to be shifting your own body weight, for example by going for a jog.
The muscles benefit massively as more aerobically efficient you become, you can hold off fatigue for longer. Running as I do, on various terrains in all weathers, makes for well defined muscular legs with strong joints which can only assist resistance training programmes. Cardio makes you stronger.
The long term benefits of cardiovascular training can provide protection against heart disease, stroke, hypertension, high cholesterol, some cancers and type 2 diabetes.