Eustress

Eustress is positive or good stress. It is the opposite of distress. Eustress is the positive stress that a person gets from riding a roller coaster, or a high speed bike, or singing in front of an audience. People may feel very good afterwards if they experience eustress. 
People often have the same physical reactions (sweating, trembling, shivering, etc.) for both eustress and distress.