Pain Perception of People Who Are Unable to Have Headache

Headaches are extremely common illnesses with a combined lifetime prevalence of 90-99% in Europe. Despite this high prevalence, there are persons who have never, in their whole life, encountered a headache. The aim of the study is to identify factors that protect against headache by studying pain perception, muscle tenderness and pain tolerance in people who never have had a headache (headache resistant) versus non-resistant controls. The investigators hope to contribute with novelty to the current understanding of headache pathophysiology and development of more efficient treatment of headache. The investigator examining: Quantitative sensory testing (cold pain threshold and heat pain threshold), Muscle tenderness (total tenderness score) and cold pressor test (time in the water and pain rating). All tests are performed the same day, by one investigator who are blinded to the grouping of the participants.