What is the best way to increase sports endurance?

Effort & Patience: The body is amazing because adapts to most things that we throw at it. Each time we push our body a little bit more, it adapts. With slow measured endurance training, the body increases the number of blood vessels going to the needed organ and muscles, and your liver stores more glycogen to give spurts of energy. So, training every muscle group along with patience, will meet your goal.

Dental check-up: Exposure to mercury from dental fillings ( silver fillings) can compete with oxygen for a binding place on the hemoglobin molecule, thereby reducing oxygen-carrying capacity. This will usually limit one's ability to break through plateaus of conditioning.