Search resultsEffects of lifestyle factors on concentrations of salivary cortisol in healthy individuals
Title
Effects of lifestyle factors on concentrations of salivary cortisol in healthy individuals
Publication type
Journal Article
Year of Publication
2009
Authors
Journal
Scandinavian Journal of Clinical and Laboratory Investigation
Volume
69
Issue
2
Pagination
242 - 250
Date published
2009
ISBN
00365513 (ISSN)
Keywords
Adult, alcohol consumption, Alcohol Drinking, arousal, article, Awakening, chemistry, coffee, controlled study, drinking, drinking behavior, Exercise, Female, Field study, food, food intake, human, Humans, hydrocortisone, Life Style, lifestyle, male, Middle Aged, normal human, priority journal, protein diet, radioimmunoassay, reference value, Reference Values, saliva, smoking, vegetable
Abstract
Objective. Salivary cortisol is widely used in occupational health research. However, many ordinary daily activities can influence the concentrations of cortisol and the interpretation of field studies. The aim of the present study was to evaluate the effect of lifestyle factors on salivary cortisol in everyday settings. Material and methods. Healthy employees participated in one or more sub-studies on the effect of eating a vegetable salad versus protein-rich mid-day meal (n=40), drinking coffee and smoking (n=12), drinking alcohol (n=32), awakening at different times (n=29) and exercising (n=21). Cortisol in saliva was measured by radioimmunoassay (RIA). Results. When eating a mid-day meal, salivary cortisol was increased by 10 % (CI -1 % to 24 %) 1 h after eating compared to before eating in the case of both types of meal. Salivary cortisol increased by 80 % (CI 9 % to 199 %) after exercising compared to before exercise. The relative awakening response was approximately 100 % when using an alarm clock on both work-days and days off. However, the awakening response was 39 % (CI 10 % to 75 %) on a day off with spontaneous awakening. No effects of alcohol, coffee or smoking were observed. Discussion. In field studies, the biological variation in salivary cortisol may be reduced by restricting physical exercise and in collecting pre-meal samples. However, the protein content of food and moderate consumption of alcohol had no effect on concentrations of cortisol. Differences in relative awakening responses on work-days and days off are related to time and mode of awakening.