After all, even if your lungs can process more oxygen, they need the requisite haemoglobin to absorb that oxygen. And this means that not only will you have more sponges to absorb and carry more oxygen to your tissues, but that your tissue can gladly unburden more carbon dioxide and rid your body off more wastes.Becoming your own blood donorWith more haemoglobin to your blood-bank credit, it follows that you have more blood. Which means that your muscles get more of this wonderful life-giving fluid. But before we get into the 'muscular' regions, let us stop and view what happens at this stage.If you are an inactive person, your blood vessels tend to become less efficient and your arteries harden due to lack of exercise. Thus, even the normal blood intake of flow becomes difficult for them. They put up a resistance which is how you get blood-pressure. For an average healthy, young person, the ideal blood pressure is 120/80. What do these figures mean? The first figure of 120 is the systolic pressure - when the heart is pumping blood into your system. The second figure of 80 is the diastolic pressure - it is when the heart has relaxed its pumping activity. In short, these two numbers show the maximum and minimum pressure in your blood vessels.When you exercise, these blood vessels become more active and open up, their tone improves and they become more elastic. Being Nature's wonderful phenomenon, they even multiply in numbers. All these changes within your body give the blood a freeway and it flows on without any resistance from the arteries. This is how your blood pressure comes back to a normal healthy level. This is the point where your stamina improves. When you first begin to exercise, you may feel a little tired because it takes time for your lungs and blood vessels to take in extra oxygen. But as your lungs begin to take in more oxygen, simultaneously; your blood vessels open up, increasing the blood supply and thus carrying more oxygen to your tissue. One day, you realise you are not tired any more! If anything, you feel invigorated, your exercise seems easy as if you are going through all those movements without any effort. What has happened?Simple. With your tissue being so rich in oxygen, the extra and now bigger blood vessels supply this life-saving gas to your heart tissue - making it more energetic and more efficient. More wastes are expelled in the process and your system is gradually purified. Which is why you feel like a million dollars and want to shout about your fitness from the rooftops!