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

One odd thing is having “runners heart” https://en.m.wikipedia.org/wiki/Athletic_heart_syndrome where your pulse gets really low at rest. Mine is regularly 45-55 at rest and sometimes doctors get concerned.

Think of your body like a car. You have different sizes, configurations, and so forth. Lifting weight is like a diesel pickup – you get power and big. Cardio is like a Civic or Prius – small, efficient. Mixing the two is where you get middle ground cars but compromise power a bit for fuel efficiency (think Ford and their Ecoboost engines).