In the curves obtained from rhinomanometry a mid-cycle rest (M.C.R.) is sometimes found to occur. The aim of this study was then to analyse the frequency of the M.C.R both in normal subjects and in subjects who had had a myocardial infarction. Rhinomanometry was therefore performed on 3 different groups of people, viz. 1 .32 normal subjects without any respiratory, cardial or any pathological problems. 2. 44 subjects who had had a myocardial infarction. 3. 34 subjects without any cardial problems. Rhinomanometry revealed that 50-60% of the second and third group had a poor nasal respiration. In the first group no M.C.R. was found in any of the subjects. In the second group over 50% of the subjects had a M.C.R. In the third group less than 50% of the subjects had a M.C.R. The x2 test was used to analyse these results as to their statistical significance. The x2 parameter was 3,84 with a significance of 95%, and 6,64 with a significance of 99%. Our result was x2=5,34 which seems to justify further study.