Abstract: The invention relates to a breathing mask comprising a mask portion (1) covering the mouth and nose of the wearer and a heat exchanger portion (2) made of a material capable of recovering heat and fitted in the mask portion (1), inhalation and exhalation air being arranged to flow through the heat exchanger portion to recover heat and moisture contained in the exhalation air and to transfer it into the inhalation air. To achieve a simple, light structure having no disadvantageous environmental effects, the mask portion (1) and the heat exchanger portion (2) are made of the same material, preferably of a biodegradable material.