blood consists of 45% blood cells and 55% plasma
heamoglobin is the main transport mode of oxygen and carbon dioxide
97% of oxgen is carried by heamoglobin which is found in the red blood cell and is called oxyheamoglobin and 3% by the plasma.
70% of co2 combines water in the red blood cells to form carbonic acid, 23% combines with heamoglobin to form carbaminoglobin and 7% dissolves in the plasma
The efficiency of the CV system to deliver oxygen and remove carbon dioxide will affect performance. Therefore an efficient heart is wasted unless the blood that it is pumping is able to deliver sufficient oxygen.