vitality

• 元气旺盛

  be full of vitality

• 大伤元气

  sap one's vitality

• 恢复元气

  get a second wind

• 工厂遭到破坏，还未恢复元气。

  The factory was destroyed and is not yet back on its feet .

• 战后没有几年经济就已经恢复元气了

  the economy recovered just a few years after the war