Describe three long-term cardiovascular changes that would allow for the increased anaerobic threshold.

Increased Stroke Volume: Over time, with consistent cardiovascular training, the heart becomes more efficient at pumping blood throughout the body. This is due to an increase in stroke volume, which is the amount of blood the heart pumps with each beat. As stroke volume increases, the heart doesn't have to work as hard to pump blood, which can increase an individual's anaerobic threshold.

Enhanced Oxygen Delivery: Another long-term adaptation is the body's improved ability to deliver oxygen to the muscles. This is achieved through an increase in capillarization, or the formation of new blood vessels, and a higher concentration of red blood cells, which carry oxygen. This allows for more oxygen to be delivered to the muscles, delaying the onset of anaerobic metabolism and thus increasing the anaerobic threshold.

Improved Lactic Acid Clearance: With regular cardiovascular training, the body becomes more efficient at clearing lactic acid, a byproduct of anaerobic metabolism, from the muscles. This is due to an increase in the number and size of mitochondria, the "powerhouses" of the cell, as well as improved efficiency of the enzymes involved in anaerobic metabolism. This allows the muscles to work harder for longer before lactic acid build-up begins to inhibit muscle contractions, thereby increasing the anaerobic threshold.