Peppermint Ambient Odor Affects Cortisol Secretion And Task Performance In Selected Tests In School Children

Abstract

Federation There is a growing set of evidences that ambient odors of essential oils have various effects on human mood, behavior and physiological state. A very little published about the impact of odors on behavior and physiology of children though it is known that children surpass adults in the ability to detect and recognize odors, describe their perceptions and preferences. The aim of our study: to evaluate the effect of low concentrations (~ 0.13 mg/m3) of peppermint oil (Sigma‐ Aldrich) on the performance of school ‐ children (age 10–11) in the course of ordinary lessons and investigate possible mechanisms underlying the effects. Among different school tests we selected arithmetic dictationtest which mainly relies on memory retrieval process. During 15 minutes the teacher dictates with pauses 8 short math exercises, adapted to the student's grade. Students write down only the answers in the corresponding order. Each experiment was set as a series of control tests with no odor alternated with tests accompanied by exposures to peppermint oil. We recorded number of errors and self‐corrections. Saliva cortisol was monitored using an ELISA technique (EIA Can‐C‐290, DBC). Individual saliva samples were taken every 15 minutes during control lesson (no odor, 45 min) and during experimental lesson (peppermint, 45 min). For the reference we also collected in identical manner individual saliva samples from adult students (age 18–21 years, n=20). All samples were kept frozen (‐30°C) until analyzed. All experiments were performed at the same time of the day. Peppermint improved performance in children (age 10–11) in arithmetic dictation test causing a significant decrease in number of mistakes as well as in number of self‐corrections. This effect was highly significant (p < 0.001, n=51) and confirmed by observations in different independent groups: students of 5‐th grade (p < 0.001, n= 25) and students of 6‐th grade (p < 0.001, n=30) as well as by repeated observations (n=3) in the same group. In our previous research (Rodionova, Minor, 2017) peppermint odor also improved performance of children (8–9 years old) in another test ‐ word dictation but not in text copying test. Word dictation and arithmetic dictation tests depend both on memory retrieval process while text copying test relies mostly on the attention. Saliva cortisol was significantly lowered by peppermint odor in children of both sexes (p< 0.001, n=14) while in adults we observed significant drop of cortisol only in female students (p< 0.01, n=10). In adult male students we did not observe changes of cortisol secretion under peppermint exposure (p>0.05, n=10). Stressful events are very common in educational settings. Stress markedly impairs memory retrieval (Vogel, Schwabe, 2016). We hypothesize that peppermint odor may facilitate memory retrieval by lowering cortisol which results in improved performance in word dictation and arithmetic dictation tests.Support or Funding InformationSupported by Russian Science Foundation 16‐15‐10312This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.