"The rage the berserker experienced was referred to as berserkergang (Berserk Fit/Frenzy or The Berserk movement). This condition has been described as follows:
This fury, which was called berserkergang, occurred not only in the heat of battle, but also during laborious work. Men who were thus seized performed things which otherwise seemed impossible for human power. This condition is said to have begun with shivering, chattering of the teeth, and chill in the body, and then the face swelled and changed its colour. With this was connected a great hot-headedness, which at last gave over into a great rage, under which they howled as wild animals, bit the edge of their shields, and cut down everything they met without discriminating between friend or foe. When this condition ceased, a great dulling of the mind and feebleness followed, which could last for one or several days.[36]"