Why do you become fitter when you exercise?

I am running again everyday and I can cover more miles and hills quicker now than 3 weeks ago.



In the beginning I needed an ambulance LOL but now when I finish my run I want more.



I guess I have more stamina but what creates stamina and why do you become fitter with exercise?

Why do you become fitter when you exercise?
Your body has the ability to adapt to physical stress. It's a defense mechanism, just like getting callouses on your hands or feet, it help protect you from harm. with cardio stamina, many things are going on, more blood is being sent to your lungs so the exchange of oxygen and carbon dioxide is more efficient. As well as you muscular endurance, the burning of sugars and oxygen become more efficient because you are able to get more oxygen to your muscles, when the balance between oxygen and sugar are not right you start burning more sugar than oxygen, when this happens your body produces lactic acid, this is a toxin that causes fatigue and makes you muscles burn.
Reply:and you have already answered your own question!
Reply:Your heart muscle gets stronger.

Your skeletal muscles get stronger %26amp; bigger.

You develop a better blood supply.

Your muscles store more glycogen

etc etc
Reply:Of course , yes . i play gymnastic and i am trainer in sport for child..
Reply:you're burning off unsightly fat when you exercise. and the reason you want more, more, more!!! is because it releases certain types of "happy hormones". that's why exercise is also recommended for relieving stress.
Reply:Dozens of reasons - your bones and muscles become stronger (including that important muscle - your heart!) Your cardiovascular system improves, your oxygen intake increases and your body's use of it becomes more efficient.



You are a walking example of 'use it or lose it' - well done you!
Reply:umm.... many many obvious reasons