High inspiratory oxygen fractions are known to induce oxidative stress and lipid peroxidation. The degrading products of oxidative stress induced lipid peroxidation are in part volatile and appear in breath where they can be measured non-invasively. However, there is lack of knowledge on the correlation of blood and breath biomarkers of oxidative stress.

This study aims to investigate the effects of a high inspiratory oxygen fraction on oxidative stress in healthy volunteers. The primary outcome is the appearance of exhaled breath biomarkers of oxidative stress by electrochemical sensors and ion mobility mass spectrometry. Secondary outcomes are changes in oxidative stress biomarkers in blood and their relationship to breath biomarkers.

Inclusion Criteria:

• healthy male volunteers who have given an oral and written informed consent

Exclusion Criteria:

• smoker or ex-smoker
• any pulmonary disease
• any heart disease
• any chemotherapy in the past
• any kind of daily medication