1 in 3 people are suffering from allergies. Many of them take antihistamines to reduce their symptoms, like sneezing and a running nose. A study from our group show that antihistamine intake in high and combined doses blunt trainings adaptations following an interval training period. However, it is unknown whether this effect stands true for conventional doses. Additionally, previous research has not been performed in people with allergies. Therefor, this PhD will focus on the role of histamine: from training adaptations to allergies.