What actually happens with your body if you increase cardio?

Question

For example you could be super in shape from a muscular perspective but have really bad cardio and vice versa.

How is cardio different from physical shape and what exactly happens in your body that makes you have more cardio?

In: 368

Answer 1

>For example you could be super in shape from a muscular perspective, but have really bad cardio and vice versa.

That usually happens as a result of hypertrophy, which is caused by steroid use. People who are muscular without good cardio-vascular health are, almost without exception, that way because they’re cheating chemically. If you exercise enough without them to obtain gains, you are going to get better heart function.

Now, I should disclaim here that carrying more muscle mass *reduces your endurance*. This is why marathon runners are skinny: all that muscle requires sugar and oxygen to fuel, and those inputs must be delivered by your circulatory system. So if you’re musclebound, that’s not “bad cardio”, you’re just metabolically expensive to support, the difference between a SUV and a motorcycle.

Now, doing cardio is beneficial in and of itself. It exercises your heart, with more intensity than your skeletal muscles, which is important because your heart muscles are a different type of muscle, which are much harder to strengthen. You can’t lift anything with your heart, so all you can really do is raise your heart rate and make the muscle work faster, over short and long periods of time.

But the thing is, all the cardio in the world still won’t make a bodybuilder able to beat that marathon runner. If you want a very good object lesson in this, watch Tour de France races. The sprinters are big and muscular, the mountain climbers thin and light. No matter how much you exercise your heart, it’s still only a pump of a certain capacity.