Red Blood cells take oxygen to the working muscles as it is required for respiration.
Red blood cells carry oxygen from the lungs to the working muscles. This oxygen is essential for aerobic metabolism, which is the process that provides energy for muscle contractions during exercise.
Oxygen
You breathe in and the oxygen goes into your lungs. Your blood picks up the oxygen and carries it to your muscles, and then goes into the cells in said muscles.
Red Blood cells bring oxygen and nutrients to the cells of the muscles.
Blood brings oxygen and nutrients to the muscle cells, it carries away carbon dioxide, other waste materials and excess heat from the cells
The cardiovascular system, specifically the red blood cells, is what transports oxygen to the muscles.
Get oxygen to your muscles
because red blood cells help to get oxygen to your muscles and vital organs
The circulatory system (blood) moves oxygen through the body to the cells.
The protein that carries oxygen to muscles is called hemoglobin. Hemoglobin is found in red blood cells and binds to oxygen in the lungs, then transports it to tissues and muscles throughout the body.
The process in muscles which uses oxygen is called respiration. Muscles, like all aerobic living cells, require oxygen for aerobic respiration, which is the process by which cells convert food into energy. So when muscles contract, they are using oxygen. When muscles do not get sufficient oxygen for contraction, problems arise. The muscle cells must use anaerobic repiration which is respiration without oxygen. They cannot do this for very long though as the byproduct of anaerobic respiration is lactic acid which causes a fall in pH.
Temporarily, yes. Giving blood means that you lose some of your red blood cells, which are what carries oxygen from the lungs and to the muscles. With less cells to carry oxygen, your muscles will have less to work with and you will get out breath faster. Blood cells are constantly replenished however, so you'll be back to level pretty soon.