Saliva cortisol in school children after acute physical exercise

We investigated if 12 min of high-intensity exercise performed within a regular school break lead to an increase in cortisol levels in primary school students. 53 students of a 4th grade (9–10 years of age) were randomly assigned to an experimental (EG) and a control group (CG). Saliva collection took place after a normal school lesson (pre-test) and after 12 min of intensive exercise in a defined heart rate (HR) interval (EG, n = 32) and control condition (movie watching) (CG, n = 21), respectively (post-test). Saliva was analyzed for cortisol. We observed a significant group by test interaction indicating a different pre-to-post-test development for EG as compared to CG. The interaction effect, however, was caused by an attenuated cortisol concentration in the control group. We argue that the control condition, in which the students watched a joyful movie, acted as a distractor, which led to a reduction of general school stress.     

Chronic stress, salivary cortisol, and alpha-amylase in children with asthma and healthy children

The present study examined whether chronic stress is related to daily life levels of salivary alpha-amylase (sAA), a marker for sympathetic activity, and cortisol in healthy children versus children with asthma. Children's sAA and cortisol levels were measured repeatedly over 2 days. Chronic stress measures included interviews with children about chronic home life stress and interviews with parents about one marker of socioeconomic status, parental education. Among children with asthma, higher chronic stress was associated with lower daily sAA output, while among healthy children, higher chronic stress was associated with flatter cortisol slopes. In conclusion, chronically stressed children with asthma showed lower salivary alpha-amylase output, indicating lower sympathetic activity, and implying a possible mechanism for increased susceptibility to symptom exacerbations. In contrast, higher cortisol levels in healthy children with chronic stress may indicate, for example, an increased risk for infectious diseases. This dichotomy emphasizes the different biological effects of chronic stress depending on illness status.     

Social influences on cortisol and behavioral responses of preweaning,periadolescent, and adult guinea pigs

In various species, the presence of an attachment figure can reduce hypothalamic-pituitary-adrenal (HPA) responses. In the guinea pig, the mother reduces HPA elevations of her young both prior to and following weaning. Recently, an unfamiliar female was also found to reduce the HPA responses of postweaning guinea pigs. The present study evaluated the specificity and ontogenetic course of the effect of the unfamiliar female. Experiment 1 found that an unfamiliar adult male did not reduce the cortisol response of periadolescent subjects during novelty exposure. Experiment 2 showed that the effect of the unfamiliar female was present as early as the second week of life. Experiment 3 found that neither an unfamiliar adult female nor male affected the cortisol response in adult guinea pigs. In all experiments, the mother reduced the cortisol elevations of her offspring. The ability to buffer the cortisol response could not be explained by the amount of agonistic behavior subjects received from the stimulus animals. Results indicate that the mother guinea pig has a persisting ability to buffer HPA responses in her developing offspring; that during at least a large portion of the time that the mother can moderate the cortisol response of her young, so too can an unfamiliar adult female, but not an unfamiliar adult male; and that the ability of social partners to moderate HPA activity is not readily predictable from behavioral interactions.     

Relationship between salivary cortisol and progesterone levels in humans

In four studies, each with multiple hormone assessments before and after positive emotion-arousing laboratory manipulations, salivary progesterone positively correlated with salivary cortisol in men and women taking hormonal contraceptives but not in freely cycling women. This is consistent with the idea that progesterone in men is largely adrenal in origin, whereas in women its sources are both ovarian and adrenal. In addition, bi-partial correlations revealed that change in cortisol was positively related to change in progesterone levels; this effect was stronger in men than in women. These findings suggest that progesterone is released from the adrenal along with cortisol in humans, due to general adrenal activation and/or possibly as an additional negative feedback mechanism to down-regulate the stress response.     

Salivary alpha amylase and cortisol responses to different stress tasks: Impact of sex

Neuro-endocrine markers such as salivary alpha amylase (sAA) and cortisol (CORT) play an important role in establishing human responses to stressful events. Whereas sAA levels reflect sympathetic system activity, salivary cortisol appears to be a valid measure for HPA axis activity. Although many studies looked at either sAA or CORT responses in reaction to stress, work still has to be done to look at the way these systems interact, especially when both systems are activated. Additionally, sex effects in CORT responses have been investigated relatively often, but possible sex differences in sAA levels and responses, or the way both systems interact has not been the focus of sufficient studies to yield a univocal conclusion. In this study we presented a group of healthy participants (n=80) with two mildly stressful tasks, consisting of an aversive picture rating task and a cold pressor stress (CPS) task. The second task was compared with a control task. We expected a rise in sAA level in response to the first task and sAA as well as CORT responses on the second task and explored the interaction between the two responses. Results indicate that sAA is indeed a sensitive marker in both psychologically and physically induced arousal paradigms, whereas a cortisol response was only observed in the CPS task. Men had higher sAA levels than women during the complete course of the study, but men and women were comparable in their responsivity to the tasks. No strong correlations between sAA and CORT responses were found.     

Patterns of salivary cortisol secretion in pregnancy and implications for assessment protocols

Cortisol is used in research as a biomarker of psychological stress. Logistical considerations argue for collecting as few samples as possible, balanced against diurnal rhythms and intra-individual variations. 100 pregnant women gave five saliva samples a day for 3 days, at waking, 30 min after waking, and 11:00 a.m., 5:00 p.m., and 9:00 p.m. Timing of collection was confirmed by monitors. Another sample was taken during a clinic visit. Using the 15 measures as the gold standard, correlations and mean area under the curve (AUC) were compared with subsets and the single clinic sample to evaluate alternate collection protocols. Five samples in 1 day, or protocols involving morning and night samples, had the highest correlations with mean AUC (correlation coefficient ranging from 0.82 to 0.88). Standardizing the clinic measurement to a single time of day did not substantially improve correlations with mean AUC. Correlations with measures of reported stress were also not strong.     

Age, rank, and personality effects on the cortisol sedation stress response in young chimpanzees

Primates and other mammals exhibit a glucocorticoid response to somatic and psychosocial stressors. The pattern and degree of response varies both within and between species, but the factors affecting within-species variability have rarely been considered. Here we describe the 90-min serum cortisol response of 14 juvenile and adolescent chimpanzees to the stress of sedation with ketamine hydrochloride. We show age differences in both baseline cortisol and time of peak cortisol, with younger individuals (ages 4-5 years) showing higher baseline levels and an earlier peak response than older individuals (ages 8-9 years). However, we found no sex or rank-related differences in any of the sedation measures: baseline cortisol, cortisol peak time, peak cortisol level, or cortisol change from baseline. We also examined the relationship between these sedation stress measures and behavioral style score, and found that individuals scoring high in the "mellow" behavioral style component showed a greater stress response than individuals scoring lower in this component. Future studies should consider the role of individual differences in age and personality in the cortisol response to stress.     

How stressful are 105 days of isolation? Sleep EEG patterns and tonic cortisol in healthy volunteers simulating manned flight to Mars

Spaceflights “environment” negatively affects sleep and its functions. Among the different causes promoting sleep alterations, such as circadian rhythms disruption and microgravity, stress is of great interest also for earth-based sleep medicine. This study aims to evaluate the relationships between stress related to social/environmental confinement and sleep in six healthy volunteers involved in the simulation of human flight to Mars (MARS500).     

Cardiovascular and cortisol reactions to acute psychological stress and cognitive ability in the Dutch Famine Birth Cohort Study

Given evidence linking blunted cardiovascular and cortisol reactions to acute stress and a range of adverse behavioral outcomes, the present study examined the associations between cardiovascular and cortisol reactivity and cognitive ability measured independently of the stress task exposure. Cognitive ability was assessed using the Alice Heim-4 test of general intelligence and two memory tasks in 724 men and women who were part of the Dutch Famine Birth Cohort Study. Blood pressure and heart rate, as well as cortisol reactivity, were measured to a battery of three standard acute stress tasks. Poorer cognitive ability was associated with lower cardiovascular reactions to stress and lower cortisol area under the curve. Our results are consistent with recent findings implicating low physiological stress reactivity in a range of adverse behavioral and health outcomes.     

A longitudinal evaluation of urinary cortisol in kennelled dogs, Canis familiaris

Urinary cortisol levels (based on cortisol : creatinine ratios) were evaluated in a randomly selected sample of shelter dogs kennelled over a 31-day period. Urine was collected on days 2, 5, 10, 17, 24 and 31 (with day 1 referring to the day of admittance to the shelter). Cortisol levels peaked on day 17 and steadily declined thereafter, although a high degree of individual variation was found, with cortisol levels peaking sooner in some dogs. Cortisol levels in kennelled dogs were significantly higher on all days except d 31 than the baseline measures taken from 20 dogs in their home environments. There were no differences between cortisol levels in male and female dogs on each day of sampling and there was no significant linear correlation between age and cortisol levels. The results are discussed in relation to stress management and the welfare of kennelled dogs.     

Diet choice, cortisol reactivity, and emotional feeding in socially housed rhesus monkeys

Chronic psychosocial stress produces an array of adverse health consequences that are highly comorbid, including emotional eating, affective disorders, and metabolic syndrome. The consumption of high caloric diets (HCDs) is thought to provide comfort in the face of unrelenting psychosocial stress. Using social subordination in female rhesus monkeys as a model of continual exposure to daily stressors in women, we tested the hypothesis that subordinate females would consume significantly more calories from a HCD compared to dominant females, and this pattern of food intake would be associated with reduced cortisol release and reduced frequency of anxiety-like behaviors. Food intake, parameters of cortisol secretion, and socio-emotional behavior were assessed for 3 weeks during a no choice phase when only a low caloric diet (LCD) was available and during a choice condition when both a LCD and HCD were available. While all animals preferred the HCD, subordinate females consumed significantly more of the HCD than did dominant females. A flattening of the diurnal cortisol rhythm and a greater increase in serum cortisol to an acute social separation occurred during the diet choice condition in all females. Furthermore, the rate of anxiety-like behavior progressively declined during the 3-week choice condition in subordinate but not dominant females. These data provide support for the hypothesis that daily exposure to psychosocial stress increases consumption of calorically dense foods. Furthermore, consumption of HCDs may be a metabolic stressor that synergizes with the psychosocial stress of subordination to further increase the consumption of these diets.     

Salivary alpha-amylase,cortisol and chromogranin A responses to a lecture: impact of sex

The aim of this study was to (1) examine the presence of stress on professors when they teach in front of 200 students and analyse objectively such stress using biomarkers such as salivary cortisol, chromogranin A (CgA) and alpha-amylase (AA) (2) investigate whether sex affects the reactivity of salivary alpha-amylase (sAA) and cortisol concentrations and the interaction of both hormonal systems. Fifty-two participants (26 women and 26 men) collected nine unstimulated saliva samples on 2 days, (one working day, and one resting day). Cortisol concentrations and AA activity measured on the teaching day were significantly higher than those noted on the resting values. No differences between the resting day and the teaching day were reported for CgA. Our results showed a cortisol response to teaching, which was characterized by an anticipatory rise. The AA level was significantly increased after the end of the lecture, and returned to the pre-lecture level 30 min after the end of the lecture. The awakening cortisol response noted on the teaching day was significantly higher in females than in males. No baseline sex differences in sAA and CgA were observed and men and women seem to have a comparable reactivity in sAA, CgA and cortisol levels on lecture stress. The mechanisms that leads to modify activity of salivary AA and CgA due to stress is not entirely understood and further research is needed to elucidate them.     

Effects of mental workload on long-latency auditory-evoked-potential,salivary cortisol,and immunoglobulin A

This paper researches on the effects of mental workload on long-latency auditory-evoked-potential (AEP), salivary cortisol, and immunoglobulin A (IgA). 20 Healthy subjects (11 males and 9 females) participated in the experiment voluntarily. The mental task consisted of two parts: arithmetic task and reading comprehension task. The Latencies of N1, P2, N2, P3, and mismatch negativity (MMN) all increased significantly after the mental tasks were adopted at all of the three recording sites: Cz, Fz, and Pz (p < 0.05). In this experiment, changes of salivary cortisol and s-IgA levels due to mental tasks were not significant. With the introduction of mental tasks, more processing resources are allocated to the primary task (mental task), and decreased processing resources available for the secondary task (auditory task), which is reflected on the increases in the latencies of probe-evoked AEP components.     

Stress and selective attention: the interplay of mood,cortisol levels,and emotional information processing

The effects of a stressful challenge on the processing of emotional words were examined in college students. Stress induction was achieved using a competitive computer task, where the individual either repeatedly lost or won against a confederate. Mood, attention, and cortisol were recorded during the study. There were four findings: (1) Participants in the negative stressor condition were faster to shift attention away from negative words than positive or neutral words; (2) attentional shifts away from negative words were associated with stress-induced mood lowering; (3) participants in the negative stress condition with elevated scores on the Beck Depression Inventory were slow to disengage attention from all stimuli; and (4) elevated depression scores were associated with lower cortisol change from baseline during the experimental phase, and with higher cortisol levels during the recovery phase. These findings point to information-processing strategies as a means to regulate emotion, and to atypical features of cognitive and adrenocortical function that may serve as putative risk markers of depression.     

Blunted cardiovascular and cortisol reactivity to acute psychological stress: A summary of results from the Dutch Famine Birth Cohort Study

The Dutch Famine Birth Cohort Study is a large population based study of late middle aged, overall healthy men and women whose health has been followed from 50 to 65 years of age. In a sample of 725 cohort members, an extensive psychological stress protocol was performed during which cardiovascular and cortisol responses were measured. In line with many previous studies, results showed that increased blood pressure responsiveness to the stress protocol was associated with an increased risk for hypertension 5 years later. However, decreased cardiovascular and/or cortisol stress reactivity were associated with obesity and the risk of becoming obese, symptoms of depression and anxiety, a poor self-reported health, poor lung function, and poor cognitive function (all p for statistical tests < 0.05). These associations generally survived adjustment for a range of potential confounders, including resting cardiovascular and cortisol activity, commitment to the stress tasks, sex, age, smoking and use of medication. Results from these studies agree with recent evidence that low biological reactivity to acute psychological stress may not always be beneficial for health but instead seems to be a marker for a range of negative health outcomes. Future studies have to point out whether low stress reactivity precedes or follows these negative health outcomes.     

The predictive value of low heart rate and heart rate variability during stress for reoffending in delinquent male adolescents

Low autonomic (re)activity is a consistent correlate of antisocial behavior in juveniles. However, longitudinal research relating autonomic measures to persistent antisocial behavior has remained scarce. Therefore, in the present study we examined the predictive value of heart rate (HR) and heart rate variability (HRV, often studied as respiratory sinus arrhythmia) for reoffending in delinquent male adolescents. At initial assessment, HR and HRV were measured at rest and in response to a public speaking task. Registered reoffending was assessed after 5-year follow-up. Attenuated HR response and stronger HRV response to stress predicted higher reoffending rates. Results provide evidence that HR/HRV reactivity are neurobiological markers for persistent juvenile antisocial behavior. Although effect sizes were small to moderate, our findings underscore the consistency of the relationship between autonomic markers and antisocial behavior.     

Interactions between salivary cortisol and alpha-amylase as predictors of children's cognitive functioning and academic performance

We examined relations between salivary cortisol, alpha-amylase (sAA), and children's cognitive and academic functioning. Of interest were curvilinear and interactive effects of these salivary measures on cognitive and academic performance. Data were based on a sample of 28 boys and 36 girls (ages 8 and 9) in the Southeastern U.S.A. Children provided resting afternoon saliva samples. Children completed standardized tests of Intellectual Ability and schools provided academic achievement information. Regression analyses demonstrated significant curvilinear relations and interactions between cortisol and sAA in the prediction of child functioning. Contrary to current models of interactions among biological systems, findings indicated some of the highest and lowest scores were predicted at moderate levels of physiological arousal. For example, children with moderate sAA and either higher or lower cortisol had low predicted scores for Reading Ability. Children with moderate cortisol and lower sAA had the highest predicted scores for Intellectual Ability. Findings suggest that the study of interactions between biological stress response systems should not be based on models of rectilinear interactions.     

Surplus dietary tryptophan reduces plasma cortisol and noradrenaline concentrations and enhances recovery after social stress in pigs

Social stress occurs in intensive pig farming due to aggressive behavior. This stress may be reduced at elevated dietary levels of tryptophan (TRP). In this study, we compared the effects of high (13.2%) vs. normal (3.4%) dietary TRP to large neutral amino acid (LNAA) ratios on behavior and stress hormones in catheterized pigs ( approximately 50 kg BW), which were exposed to social stress by placing them twice into the territory of a dominant pig ( approximately 60 kg) for 15 min. Pre-stress plasma TRP concentrations were 156+/-15 vs. 53+/-6 micromol/l (p<0.01) in pigs on the high vs. normal TRP diets, respectively. Pre-stress plasma cortisol and noradrenaline concentrations were twofold (p<0.01) and 1.4-fold (p<0.05) lower but plasma adrenaline concentration was similar in pigs on the high vs. normal TRP diets, respectively. During the social confrontations, pigs on the high vs. normal TRP diets show a tendency towards reduced active avoidance behavior (3.2+/-1.1 vs. 6.7+/-1.2 min, p<0.1) but their physical activity (8.5+/-0.6 vs. 10.2+/-0.8 min) and aggressive attitude towards the dominant pig (11+/-3 vs. 7+/-2 times biting) were similar. Immediate (+5 min) post-stress plasma cortisol, noradrenaline and adrenaline responses were similar among dietary groups. After the social confrontations, the post-stress plasma cortisol, noradrenaline and adrenaline concentrations and/or curves (from +5 min to 2 h) were lower/steeper (p<0.05) in pigs on the high vs. normal TRP diets. In summary, surplus TRP in diets for pigs (1) does not significantly affect behavior when exposed to social stress, (2) reduces basal plasma cortisol and noradrenaline concentrations, (3) does not affect the immediate hormonal response to stress, and (4) reduces the long-term hormonal response to stress. In general, pigs receiving high dietary TRP were found to be less affected by stress.     

Salivary cortisol, stress and mood in healthy older adults: the Zenith study

The aims of this study were to investigate the relationship between salivary cortisol, stress and mood and to look at the circadian rhythms of positive (PA) and negative (NA) mood in older adults. The participants were 41 healthy adults aged 55-69 years, recruited in Northern Ireland as part of the European Commission-funded Zenith project. Salivary cortisol samples were obtained twice a day (2.30 p.m. and 10.30 p.m.) for 7 consecutive days in conjunction with momentary measures of positive (PA) and negative mood (NA), using PANAS and a trait measure of perceived stress (Perceived Stress Scale). Salivary cortisol levels were measured using an enzyme-linked immunoassay kit. Higher perceived stress levels were associated with lower afternoon PA (r=-0.46, p=0.003) and higher afternoon (r=0.43, p=0.007) and evening (r=0.45, p=0.004) NA. Lower afternoon PA was correlated with higher evening cortisol concentrations (r=-0.47, p=0.002). Greater afternoon PA variability was associated with higher evening cortisol concentrations (r=0.38, p=0.015). A high intra-class correlation between cortisol and positive mood was found (r=0.67, p=0.009). Previously established rhythms for positive and negative mood were confirmed. Interestingly, there was no association between salivary cortisol levels and perceived stress in these healthy older adults. Further, more extensive research is required to better understand the apparent interplay between these variables and ageing.