The primary function of red blood cells is to transport oxygen from the lungs to the body’s tissues and return carbon dioxide for exhalation. This function is vital during exercise, as increased physical activity demands more oxygen to fuel the muscles. An increase in red blood cell production can enhance oxygen delivery, thus improving endurance and performance. Athletes often seek to optimize their red blood cell levels naturally through proper nutrition, hydration, and training techniques like altitude training, which can stimulate the production of these crucial cells.