[The active butanol detection threshold remains the same during exercise]. / Die aktive Butanol-Wahrnehmungsschwelle bleibt bei körperlicher Belastung gleich.

BACKGROUND: The active butanol detection thresholds (B-DT), determined using the sniffin' sticks, show a high intra- and inter-individual test-retest reliability, although the internal stimulus concentration may vary considerably depending on the dilution of the external stimulus concentration with odorless ambient air during active sniffing. There are various hypotheses for this surprising result. In this study, it should be tested whether a larger respiratory effort (vigor) under physical stress changes the active B-DT. METHODS: In 28 young, healthy, normosmic adults, sitting on a stationary bicycle ergometer at rest phase, during aerobic exercise and in the recovery phase, the monorhinal B-DT using Sniffin' Sticks were determined. Various vital parameters such as blood pressure, heart frequency, body temperature, respiratory frequency and blood lactate characterized the three test phases. The individual stress perception was estimated according to the Borg scale. RESULTS: The B-DT did not change in the three test phases. All examined vital parameters were significantly larger in the loading phase than in the resting phase. In the case of a moderate to severe stress sensation (Borg-scale: 13-15), an aerobic physical stress could be confirmed on the basis of the vital parameters. CONCLUSIONS: The investigations support the hypothesis that vigor is not the decisive factor for a constant olfactory perception of external equal stimulus concentrations. The integration of internal stimulus concentration and nasal flow velocity and the empirical evaluation of the current odor concentration probably play a greater role.

[Aerobic exercises during mouth breathing do not change the detection threshold of H2S]. / Aerobe Belastung bei Mundatmung verändert die Wahrnehmungsschwelle für H2S nicht.

BACKGROUND: In a previous study, the detection threshold for H2S during aerobic exercise worsened with forced nasal breathing. The cause remained unclear. It is to be examined how the detection threshold changes with exclusive mouth breathing. MATERIAL AND METHODS: During a resting phase, an aerobic physical load and subsequent recovery phase, different H2S concentrations were applied inspiratory-synchronously intranasal using a flow-olfactometer in a staircase procedure. The missing nasal breathing was objectified online and offline. The reaction times were determined. In parallel, various vital parameters have been measured. RESULTS: The passive detection thresholds for H2S between the load and recovery phases did not differ. In the resting phase, the threshold was highest. The reaction times were not different in the three experimental phases. CONCLUSION: An increased sympathetic tone, resulting from an approximately half-hour aerobic exercise, did not change the passive olfactory threshold for H2S during oral respiration compared to the subsequent recovery period. The high olfactory threshold in the resting phase might be explained by initial adaptation difficulties to the experimental conditions.

[Aerobic exercises worsen the detection threshold of short H2S pulses]. / Aerobe Belastung verschlechtert die Wahrnehmungsschwelle kurzer H2S-Impulse.

BACKGROUND: Whether smelling is reduced during aerobic exercise is described contradictorily in the sparse literature. MATERIAL AND METHODS: To clarify this question, in healthy subjects the passive detection thresholds for short H2S stimuli were determined by means of a flow olfactometer in an inspiration-synchronous manner during nasal breathing in a staircase procedure during a resting phase, a subsequent submaximal load on a bicycle ergometer and a subsequent recovery phase. In parallel, the measurements of heart rate, blood pressure, blood lactate and body temperature were monitored to confirm an aerobic exercise. RESULTS: The participants achieved the highest values for the detection threshold in the load phase. By means of rm-ANOVA and post-hoc tests, a significant difference in the mean values of detection thresholds between the measurements at rest and during cycling as well as between the recovery and load phases was observed. However, the mean values of the detection thresholds between the resting and recovery phases did not differ. CONCLUSION: The worsening of olfactory detection thresholds during acute aerobic physical exercise and their immediate improvement during recovery phase to rest values suggests that the detection threshold is influenced by exercise. The most probable cause for this is a dilution effect caused by additional inflowing neutral ambient air in the case of forced nasal breathing.

[Testing the sense of smell using validated procedures]. / Die Prüfung des Riechvermögens mit validierten Verfahren.

There is a growing interest into the investigation of smell disorders in both research and clinical practice. For psychophysical ("subjective") investigations related to the sense of smell a variety of test kits are available, namely the various "Sniffin' Sticks" kits, the UPSIT (University of Pennsylvania Smell Identification Test) or the CCSIT (Cross-Cultural Smell Identification Test). Recording of olfactory evoked potentials (OEPs) and respiration olfactometry can be used for diagnosing smell dysfunctions in a more objective way.

[Testing the sense of taste using validated procedures]. / Die Prüfung des Schmeckvermögens mit validierten Verfahren.

Psychophysical tests related to the sense of taste are usually less complex than those of the sense of smell. In addition to global tests a regional examination of the sense of taste might be indicated to search for nerve lesions. There are numerous validated psychophysical tests available based on the administration of liquid or solid substrates. The use of electrical currents (electrogustometry) is especially feasible for a rapid regional testing. The registration of gustatory event-related potentials to objectify results from psychophysical examination is possible although limited to a few centers world-wide.