28 healthy volunteers, 14 males and 14 females, aged from 18 to 45 years with normal nasal breathing were measured rhinomanometrically after physical exercise on an ergometer bicycle after increase in loads by steps of 25, 50, 75, 100, 125 and 150 watt and also 2, 5 and 10 minutes after physical exercise with 150 watt. V15 (nasal air flow related to 15 mm H2O) was registered. A new rhinomanometer with a Prandtl type tube was employed for measuring a relationship between nasal airflow (V2) and transnasal pressure (delta p) yielding a straight line in the V2-delta p-diagramm using nozzles and active anterior method. An increase of V15 up to 150 watt was measured. The average V15 value of the 28 persons for the total nose without decongestion the nasal mucosa before physical exercise at rest is 0.69 l/s and after physical exercise up to a load of 150 watt 1.09 l/s, so that the increase of V15 is 0.4 l/s. This decongestion effect of the nasal mucosa is twice to three times larger than the decongestion after xylometazolin spray 0.1% (Otriven 0.1%). The medicamentous decongestion effect of V15 = 0.14 l/s is as large as the decongestion effect caused by physical exercise with a load of 25 to 50 watt. A decrease of V15 is measured reaching a normal value within 15 minutes. The rhinomanometrical normal values under physical exercise within a load of 0 to 150 watt of healthy volunteers with normal nasal breathing are readable directly in a V15-watt diagramm for the right and left nasal cavity and the total nose based on the average values of all 28 volunteers. Individual variations of the maximal decongestion effect during physical exercise are discussed.