stamina

(n) - Stamina is physical or mental strength that allows you to continue doing something for a long time without getting tired.

• Synonyms: strength, endurance, "stick-to-it-iveness," tolerance
• Antonyms: laziness, weakness
• Etymology:1670s Latin, from stamina meaning "threads." The current meaning of "power to resist or recover, strength, endurance" was first recorded in 1726.
• Example: The more you read, the more you want to read... this is proof that you have to build up stamina for reading!

Let's see if you have the stamina to read for 5 minutes straight - without looking up at this cool timer!