The heart pumps blood quickly. This blood is full of oxygen and flows directly to the working muscles. But loading oxygen is only half the battle. The real problem is transporting oxygen from the carrier to the muscle cells. It’s an exciting exchange. Oxygen comes in and carbon dioxide comes out.
The key factor in this exchange is hemoglobin, a protein packed inside red blood cells. It is responsible for most of the body’s oxygen supply. Hemoglobin is flexible. It binds oxygen and binds carbon dioxide. But which one to stick to depends on the situation. Specifically, it monitors three things: oxygen levels, carbon dioxide levels, and pH.
Under normal resting conditions, hemoglobin follows strict rules.
transports carbon dioxide to the lungs. There is fresh air. High oxygen content. Since you have just exhaled carbon dioxide, your carbon dioxide level is low. Hemoglobin is relaxed. It releases carbon dioxide and traps oxygen.
It then travels through the heart and into the arteries. It reaches the muscles. The opposite is also true. Your cells burn fuel. Oxygen levels are low. Carbon dioxide is high. Hemoglobin releases oxygen. Absorbs waste carbon dioxide. It returns to the lungs. This cycle repeats itself.
The system works fine until it is stressed.
pH change during strength
Exercise changes everything. Your metabolism will skyrocket. Your cells work more actively. They produce more acid. In particular, you get more hydrogen ions. Lactic acid builds up. The local pH of the muscle tissue decreases. It will be more sour.
This acidity is important. When the pH is low, the binding between hemoglobin and oxygen is weakened. Reduces the attractiveness of hemoglobin. The protein relaxes. It releases more oxygen than when it is at rest.
This is not a bug. This is a feature. The body needs more oxygen when working. By lowering the pH, the body is forced to unload oxygen from hemoglobin. More oxygen reaches the muscles. You can continue.
Remove the trash
Hard work has its price. You create waste. Your body produces lactic acid, carbon dioxide, adenosine and hydrogen ions. If these byproducts remain, they can clog the system. In order for the muscle to continue to contract, it must be removed.
The extra blood flow to your muscles serves two purposes. Bring fresh oxygen. It also acts as a garbage collector. Hemoglobin in the blood helps transport carbon dioxide. Other systems do the rest. However, the ability of hemoglobin to change its binding depending on pH and waste levels is important. It ensures that your muscles get what they need while removing metabolic waste.
It’s a delicate balance. At some point you will be saturated. Next thing you know, you’re empty. It happens automatically, not through conscious thought, but through chemistry and physics. Just keep going. Blood continues to flow. Hemoglobin is constantly changing gears.
