A dip in the ocean in January is horrifying to some people but invigorating to others. Invigorating describes something that makes you feel strong and revitalized.
A long walk, rousing music, a drink of water when you're thirsty — all of these can be invigorating, or deeply refreshing. Invigorating contains the word vigor, which means a hearty strength. You can talk about any activity that might give you that kind of strength as invigorating. Invigorating comes from the same root as vigorous, the Latin vigere, which means "be lively, flourish, or thrive".