The purpose of this study is to find out how the provocation of the nose changes breathing style (specifically, frequency and tidal volume changes)

It is intended to clarify on both healthy and birch pollen allergic adults how the provocation of the nose with the birch pollen, dilutant and xylometazoline affect the breathing style (breathing pattern) and how these possible changes could be controlled in the measurement of the breathing with respiratory effort belts. In addition to this, our intention is to clarify the effect of the facial mask on the breathing.

The allergic and control subjects undergo nasal provocation in 2 sessions. The first is done with birch pollen extract (should block the nose in allergic subjects) and the second with xylometazoline (should open the nose).

The mask group undergo similar measurements without nasal exposures.

The second objective of the study is to clarify if there are differences between the allergic and control subjects in the function of the autonomous nervous system during these provocations. This is done with the heart rate variability analysis method.

Inclusion Criteria:

• Birch pollen allergic subjects must have clear nasal symptoms during the birch pollen season and birch specific IgE >= 0.70
• Healthy subjects: birch specific IgE < 0.35
• The subjects are not allowed to be under medication that affects the function of their nose during a specific time period before the measurement
• They have to be free of any acute respiratory symptoms during the prior two weeks to the measurements
• Before measurement, they are not allowed to have heavy meal or sport
• They are not allowed to have caffeine or other stimulants for 12 hours or alcohol for 24 hours.

Exclusion Criteria:

• Heart diseases
• Brain circulatory disorders
• Surgical operations of nose
• Chronic nasal symptoms
• Pregnancy
• Smoker