Why is cardiovascular endurance important for cross country running?

Cardiovascular endurance is imperative for cross country running because you are putting your body to intense aerobic activity for more than one hour every day. When you train for cross country, you are most likely running approximately 50 miles a week (it varies among high schools, and is a lot more in college!). Therefore, you must have a strong heart to endure the long distance.

Moreover, it is imperative because cross country races are either 3 miles, 5000m, 8000m, 10000m. Clearly, this is a large distance to be running at a fast pace. Cardiovascular endurance will help you maintain your pace for that distance.