Afternoon Salivary Cortisol Research Articles

Impact of modified yoga compared to conventional therapy on pain characteristics, cardiorespiratory endurance, body flexibility, salivary cortisol levels, and levels of depression, in patients with cervicogenic headache, a randomized clinical trial

Introduction: Cervicogenic Headache (CGH) is a chronic headache with a significant prevalence. The pain intensity associated with CGH is usually severe, significantly diminishing the quality of life for those affected. Yoga is thought to promote muscle endurance, body flexibility, and muscle elasticity. The author seeks to explore the potential benefits of yoga for individuals suffering from CGH. Methods: This was a Randomized Control Trial (RCT), conducted at Qadr Hospital, Banten, focusing on patients aged 18-60 years who visited the neurologist with headaches. The inclusion criteria were patients who had chronic headache originating from the neck (CGH) for a minimum of 12 weeks with at least 6 weeks of treatment. The subjects were divided into two groups; the control group, which received medication, and the yoga group, which received medication as well as participated in modified yoga exercises for 12 weeks, 2 times per week with duration of 90 minutes. After 3 months of intervention, the predictors were re-examined. Result: Out of 53 subjects, 26 were in the control group and 27 were in the yoga group. There were significant differences between the two groups in mean VO2max after the intervention (p = 0.048), mean body flexibility after the intervention (p < 0.001), mean afternoon salivary cortisol after the intervention (p = 0.027), pain characteristics (intensity, frequency, duration (p < 0.001)), and level of depression (p < 0.001). Conclusion: Modified yoga gives better clinical improvement compared to conventional therapy for CGH patients.

Is There a Relationship Between Cortisol and Treatment Response in Chronic Aphasia?

Purpose: To evaluate whether levels of cortisol, a stress-related hormone, predicted response to intensive speech–language intervention for individuals with chronic aphasia (IWA). Secondary analyses explored baseline cortisol levels, change following intervention, association between cortisol levels and aphasia severity, self-reported communicative distress, and chronic stress. Method: Afternoon salivary cortisol levels were measured in 14 IWA during the first and last weeks of a 4-week intensive speech–language intervention epoch. Behavioral outcome measures were collected pre- and postintervention. Results: Cortisol levels did not significantly predict treatment response in this sample of IWA, although a positive trend was present. Baseline cortisol levels were not abnormally elevated, did not change from pre- to postintervention, and were not significantly correlated with any of the behavioral outcome measures. Discussion: Although afternoon salivary cortisol levels did not robustly predict treatment response in this participant sample, future studies may be warranted that include IWA with elevated levels of cortisol at pretreatment.

Hospitalization stress and coping in children

Hospitalization is stressful for children and their families that can affect health outcomes, depending on how they face the situation. This study analyzed how children deal with indicators of physiological and psychological stress related to hospitalization. Participants were 20 children aged five years old, most of them hospitalized for chronic diseases, in a public hospital in Cuiabá, MT. The following were applied individually in the playroom library: a) Morning and late afternoon salivary cortisol index to measure physiological stress; b) Interview script on illness and hospitalization - child version; and c) Hospitalization Coping Scale (COPE-H). Salivary cortisol was above that indicated in four children. More than half of the sample reported having difficulties caused by the disease to perform several activities; invasive medical procedures are more aversive. They also presented psychological stress responses, with coping of involuntary and voluntary disengagement within the mean age. They reported adaptive strategies to deal with hospitalization, such as watching TV, talking, taking medication and, especially, playing, evaluated as a stress reducer by almost half of the children. However, half of the sample presented a poorly adaptive coping pattern of hospitalization below that expected for their age. There were no significant correlations between salivary cortisol index and coping. Consistent with the literature of the area on the limitations imposed by hospitalization and psychosocial consequences for the child and the caregiving family, the results indicate the importance of interventions in the coping of hospitalization for this population in this age group.

Estresse da hospitalização e seu enfrentamento em crianças

Hospitalization is stressful for children and their families that can affect health outcomes, depending on how they face the situation. This study analyzed how children deal with indicators of physiological and psychological stress related to hospitalization. Participants were 20 children aged five years old, most of them hospitalized for chronic diseases, in a public hospital in Cuiabá, MT. The following were applied individually in the playroom library: a) Morning and late afternoon salivary cortisol index to measure physiological stress; b) Interview script on illness and hospitalization - child version; and c) Hospitalization Coping Scale (COPE-H). Salivary cortisol was above that indicated in four children. More than half of the sample reported having difficulties caused by the disease to perform several activities; invasive medical procedures are more aversive. They also presented psychological stress responses, with coping of involuntary and voluntary disengagement within the mean age. They reported adaptive strategies to deal with hospitalization, such as watching TV, talking, taking medication and, especially, playing, evaluated as a stress reducer by almost half of the children. However, half of the sample presented a poorly adaptive coping pattern of hospitalization below that expected for their age. There were no significant correlations between salivary cortisol index and coping. Consistent with the literature of the area on the limitations imposed by hospitalization and psychosocial consequences for the child and the caregiving family, the results indicate the importance of interventions in the coping of hospitalization for this population in this age group.

DNA methylation of the glucocorticoid receptor gene predicts substance use in adolescence: longitudinal data from over 1000 young individuals

Early life stress has been linked to increased methylation of the Nuclear Receptor Subfamily 3 Group C Member 1 (NR3C1) gene, which codes for the glucocorticoid receptor. Moreover, early life stress has been associated with substance use initiation at a younger age, a risk factor for developing substance use disorders. However, no studies to date have investigated whether NR3C1 methylation can predict substance use in young individuals. This study included adolescents 13–14 years of age that reported no history of substance use at baseline, (N = 1041; males = 46%). Participants contributed saliva DNA samples and were followed in middle adolescence as part of KUPOL, a prospective cohort study of 7th-grade students in Sweden. Outcome variables were self-reports of (i) recent use, (ii) lifetime use, and (iii) use duration of (a) alcohol, (b) tobacco products, (c) cannabis, or (d) any substance. Outcomes were measured annually for three consecutive years. The predictor variable was DNA methylation at the exon 1 F locus of NR3C1. Risk and rate ratios were calculated as measures of association, with or without adjustment for internalizing symptoms and parental psychiatric disorders. For a subset of individuals (N = 320), there were also morning and afternoon salivary cortisol measurements available that were analyzed in relation to NR3C1 methylation levels. Baseline NR3C1 hypermethylation associated with future self-reports of recent use and use duration of any substance, before and after adjustment for potential confounders. The overall estimates were attenuated when considering lifetime use. Sex-stratified analyses revealed the strongest association for cigarette use in males. Cortisol analyses revealed associations between NR3C1 methylation and morning cortisol levels. Findings from this study suggest that saliva NR3C1 hypermethylation can predict substance use in middle adolescence. Additional longitudinal studies are warranted to confirm these findings.

Extremely low birth weight influences the relationship between stress and telomere length in adulthood.

This study examined the link between two biological markers of stress vulnerability at 22-26 years of age and telomere length at 30-35 among extremely low birth weight (ELBW; <1000 g) survivors and normal birth weight (NBW; >2500 g) control participants. Sixteen ELBW and 22 NBW participants provided baseline afternoon salivary cortisol samples and resting frontal electroencephalogram (EEG) alpha asymmetry data at 22-26 years. Buccal cells were assayed for telomere length at 30-35 years. Analyses controlled for sex, postnatal steroid exposure, childhood socioeconomic status, time of cortisol sample collection, and body mass index at 22-26 years. Salivary cortisol and frontal asymmetry at age 22-26 independently predicted telomere length at age 30-35, such that relatively higher cortisol and greater relative right frontal asymmetry at rest predicted telomere shortening among NBW controls, but not among ELBW survivors. However, similar associations were not noted in ELBW survivors, suggesting that ELBW survivors may have different mechanisms of stress coping as a result of their early-life exposures. These findings offer preliminary evidence in support of the role of stress in the genesis of cellular senescence at least among those born at NBW, but that these links may differ in those born preterm.

Remitted depression and cognition in HIV: The role of cortisol and inflammation

In major depressive disorder (MDD) and remitted MDD (rMDD) alterations in cortisol and inflammation are associated with cognitive difficulties, but these relationships have not been investigated in HIV. We used secondary data from a placebo-controlled, cross-over study of cognitive performance following a probe of the hypothalamic-pituitary-adrenal (HPA) axis (low dose hydrocortisone; LDH 10 mg) in 65 people with HIV (PWH; 36 women). Using placebo data, we examined sex-specific associations between two biomarkers - basal afternoon salivary cortisol and salivary inflammatory cytokines - cognition, and rMDD. Salivary cortisol and inflammatory biomarkers were sampled across the 5 -h study. The panel of inflammatory markers included interleukin (IL)-6, IL-8, IL-1β, tumor necrosis factor-(TNF)-α, CRP, interferon gamma-induced protein (IP-10), monocyte chemotactic protein (MCP)-1, monokine induced by interferon (MIG), matrix metalloproteinase MMP-9, and MMP-1. Learning, memory, attention/concentration, and executive function were assessed 30 min and 4 h after the placebo intervention; visuospatial ability was also assessed 30 min after the placebo intervention. For women but not men with HIV, basal cortisol concentrations were higher in rMDD versus noMDD groups, and related to poorer learning and memory. For men and women with HIV, basal inflammatory cytokines were higher in rMDD versus noMDD groups, but were negatively related to cognition independent of rMDD status. Cortisol and cytokines relate to cognition in PWH, but the associations depended on sex, rMDD status, and their interaction.

Evidence for a physiologic home–school gap in children of Latina immigrants

Abstract The “Latino Health Paradox” denotes a well-established trend wherein foreign-born Latino immigrants arrive with protective health benefits which dissipate and sometimes reverse into health disparities in the second and subsequent generations. The origins and mechanism behind this paradox remain poorly understood. This study investigates whether physiological stress profiles in children of Latina immigrants (CoLIs) as compared with the children of Latina Americans (CoLAs) and of non-Latina Americans (ConLAs) might help explain how health advantages can be lost during acculturation to even result in health disparities. Because studies of ethnicity/nativity often confound poverty and ethnicity/nativity groups, we also examine differences in physiologic stress profiles by income. We focus on physiologic profile differences between ethnicity/nativity groups and by poverty category at home and in Early Childhood Education (ECE) environments. Using multi-level modeling, we compare morning and afternoon salivary cortisol levels between ECE and home environments in 256 children (32% CoLIs), while controlling for child, child care, and teacher characteristics. Results demonstrated that overall, cortisol on child care mornings was lower than on home mornings, and that among children living in poverty home and child care morning cortisol differed less than for children not living in poverty. We find that CoLIs exhibit a flatter slope on child care days than do ConLAs. We also find that among children in classrooms with lower average poverty exposure, cortisol decline across the day is steeper on child care days. Importantly, teacher language may act as a buffer to CoLIs on child care days, resulting in a steeper decline at child care. Implications for policy and practice, including supporting the availability of bilingual teachers are discussed.

Behavioral Interventions for Infant Sleep Problems: A Randomized Controlled Trial.

To evaluate the effects of behavioral interventions on the sleep/wakefulness of infants, parent and infant stress, and later child emotional/behavioral problems, and parent-child attachment. A total of 43 infants (6-16 months, 63% girls) were randomized to receive either graduated extinction (n = 14), bedtime fading (n = 15), or sleep education control (n = 14). Sleep measures included parent-reported sleep diaries and infant actigraphy. Infant stress was measured via morning and afternoon salivary cortisol sampling, and mothers' self-reported mood and stress. Twelve months after intervention, mothers completed assessments of children's emotional and behavioral problems, and mother-child dyads underwent the strange situation procedure to evaluate parent-child attachment. Significant interactions were found for sleep latency (P < .05), number of awakenings (P < .0001), and wake after sleep onset (P = .01), with large decreases in sleep latency for graduated extinction and bedtime fading groups, and large decreases in number of awakenings and wake after sleep onset for the graduated extinction group. Salivary cortisol showed small-to-moderate declines in graduated extinction and bedtime fading groups compared with controls. Mothers' stress showed small-to-moderate decreases for the graduated extinction and bedtime fading conditions over the first month, yet no differences in mood were detected. At the 12-month follow-up, no significant differences were found in emotional and behavioral problems, and no significant differences in secure-insecure attachment styles between groups. Both graduated extinction and bedtime fading provide significant sleep benefits above control, yet convey no adverse stress responses or long-term effects on parent-child attachment or child emotions and behavior.

Autonomic reactivity and hypothalamic pituitary adrenal axis dysregulation in spouses of Oklahoma City bombing survivors 7 years after the attack

The objective of this exploratory pilot study was to examine autonomic reactivity and hypothalamic pituitary adrenal axis dysregulation in spouses of highly exposed survivors of the 1995 Oklahoma City bombing. This study compared psychiatric diagnoses and biological stress markers (physiological reactivity and cortisol measures) in spouses of bombing survivors and matched community participants. Spouses were recruited through bombing survivors who participated in prior studies. Individuals with medical illnesses and those taking psychotropic medications that would confound biological stress measures were excluded. The final sample included 15 spouses and 15 community participants. The primary outcome measures were psychiatric diagnoses assessed with the Diagnostic Interview Schedule for DSM-IV (DIS-IV). Biological stress markers were physiological reactivity and recovery in heart rate and blood pressure responses to a trauma interview and cortisol (morning, afternoon, and diurnal variation). Compared to the community participants, spouses evidenced greater reactivity in heart rate, systolic blood pressure, and diastolic blood pressure; delayed recovery in systolic blood pressure; and higher afternoon salivary cortisol. The results support the need for further research in this area to clarify post-disaster effects on biological stress measures in the spouses of survivors and the potential significance of these effects and to address the needs of this important population which may be overlooked in recovery efforts.

Aphasia severity and salivary cortisol over time

The current study explored the complicated interplay between aphasia and the stress biomarker, cortisol, in left-hemisphere (LH) and right-hemisphere (RH) stroke patients. Nineteen LH patients and 12 RH patients began the study between one to six months post stroke and were followed for three months. During this time, language skills were assessed monthly while afternoon salivary cortisol samples were collected biweekly. The LH and RH groups showed improvements in language test scores over the course of three months; however, only naming skills in the RH group appeared to be associated with afternoon salivary cortisol levels. Furthermore, contradicting previous reports regarding laterality and cortisol regulation in humans, the current study found that both LH patients and RH patients exhibited similar afternoon salivary cortisol levels across all time points.

Exploring Biobehavioral Outcomes in Mothers of Preterm Infants

To evaluate physiologic measures of stress with self-reported perceived stress and depressive symptoms among mothers of preterm babies currently hospitalized in an NICU. This was a cross-sectional, descriptive, single-visit study of 20 mothers of hospitalized preterm infants. Data collected included self-report behavioral measures and a brief structured interview. Biological data were available on 17 mothers. Data were analyzed using descriptive and inferential statistics. Mothers reported high levels of stress and depressive symptoms. Higher levels of stress and more depressive symptoms were associated with higher levels of certain serum cytokines, higher levels of waking and afternoon salivary cortisol, and abnormal diurnal patterns of salivary α-amylase. A NICU admission is a stressful time for which families typically have not had the opportunity to prepare. Mothers with higher levels of stress and depressive symptoms may be at higher risk for poorer physical and mental health. This study highlights the high levels of stress and depressive symptoms that may be experienced by mothers of preterm infants, and suggests the potential value of developing effective strategies to target maternal psychological distress.

Abolished circadian rhythm of salivary cortisol in elite artistic gymnasts

The aim of this study was to evaluate the effects of intensive physical exercise and acute psychological stress during high level athletic competition as reflected on the levels of salivary cortisol in elite artistic gymnasts (AGs). The study included 239 AGs (142 females-97 males) who participated in the European Championship of Gymnastics in 2006 and 81 adolescents (40 females-41 males), matched for age, as controls. All athletes participated voluntarily in all or parts of the study, providing samples or data for each of the variables measured. Height, weight, body fat, lean body mass (LBM), bone age and Tanner stage of puberty were assessed and data concerning the time of thelarche, adrenarche and menarche as well as, the onset and the intensity (hours per week) of training were obtained. Saliva samples were collected, the morning before training and in the afternoon shortly after the competition. From controls, the saliva samples were collected in the morning. Cortisol concentrations were measured using a chemiluminescence method. Acute stress was assessed using a questionnaire designed for the study. No difference was found between morning and afternoon salivary cortisol levels in both male and female AGs (females: AM: 15.45±7.45nmol/l vs PM: 15.73±9.38nmol/l; males: AM: 10.21±5.52nmol/l vs PM: 9.93±13.8nmol/l, p>0.05). Female AGs presented higher levels of morning salivary cortisol than female controls (p<0.05). Both male and female AGs had higher degree of psychological stress in comparison with controls (p<0.001, p<0.013, respectively). Female AGs had higher morning and afternoon salivary cortisol levels (p<0.01, p<0.01, respectively) and higher degree of stress (p<0.003) than males. In elite AGs the diurnal rhythm of salivary cortisol has been abolished, probably due to the strenuous training and competition conditions. Female AGs presented higher levels of morning salivary cortisol and psychological stress compared to both male AGs and female controls. The long term consequences of these modifications of the HPA axis remain to be elucidated.

Trauma exposure and hypothalamic–pituitary– adrenal axis functioning in mentally healthy Dutch peacekeeping veterans, 10–25 years after deployment

Hypothalamic-pituitary-adrenal (HPA) axis alterations have been found in veterans with posttraumatic stress disorder (PTSD). It is unclear whether trauma exposure during adulthood in the absence of psychopathology is also associated with HPA-axis dysregulation. Thirty-six trauma-exposed peacekeepers, 23 nonexposed peacekeepers, and 25 nonexposed civilians, all without lifetime psychopathology were studied. Basal HPA-axis functioning was assessed with salivary cortisol samples obtained over 2 days. HPA-axis reactivity was assessed with the dexamethasone/corticotropin-releasing hormone test. Lower afternoon salivary cortisol levels were found in both veteran groups versus controls after adjustment for confounders. The authors concluded that this study does not support the idea that HPA-axis functioning is durably altered by trauma exposure during adulthood in men.

Early Risk Factors and Developmental Pathways to Chronic High Inhibition and Social Anxiety Disorder in Adolescence

Evidence suggests that chronic high levels of behavioral inhibition are a precursor of social anxiety disorder. The authors sought to identify early risk factors for, and developmental pathways to, chronic high inhibition among school-age children and the association of chronic high inhibition with social anxiety disorder by adolescence. A community sample of 238 children was followed from birth to grade 9. Mothers, teachers, and children reported on the children's behavioral inhibition from grades 1 to 9. Lifetime history of psychiatric disorders was available for the subset of 60 (25%) children who participated in an intensive laboratory assessment at grade 9. Four early risk factors were assessed: female gender; exposure to maternal stress during infancy and the preschool period; and at age 4.5 years, early manifestation of behavioral inhibition and elevated afternoon salivary cortisol levels. All four risk factors predicted greater and more chronic inhibition from grades 1 to 9, and together they defined two developmental pathways. The first pathway, in girls, was partially mediated by early evidence of behavioral inhibition and elevated cortisol levels at age 4.5 years. The second pathway began with exposure to early maternal stress and was also partially mediated by childhood cortisol levels. By grade 9, chronic high inhibition was associated with a lifetime history of social anxiety disorder. Chronic high levels of behavioral inhibition are associated with social anxiety disorder by adolescence. The identification of two developmental pathways suggests the potential importance of considering both sets of risk factors in developing preventive interventions for social anxiety disorder.

Effects of Physical Workload on Salivary Cortisol Level

Objectives: Workload is known to affect the hypothalamus-pituitary-adrenal axis. Although many studies had revealed that job stress related factors could affect the neuroendocrine system among blue-collar workers, these studies had limitations as they had not evaluated the workload by objective methods which took into consideration individual physiological differences. This study was conducted to evaluate the effects of physical workload adjusted job stress on cortisol regulation by using objective tools for workers having various job tasks. Methods: Among 110 foundry workers, shipyard workers, and fine machine assemblers for whom saliva samples were obtained, 102 without any past history of conditions that could affect hormonal regulation such as diabetes, and hypertension were included in this study. Among the 102 study participants, 15 workers whose saliva for morning or afternoon or heart rate monitoring data was not attained were excluded from the final analysis. Workload was evaluated by RHR (relative heart rate) using a heart rate monitor, and job stress was evaluated by Karasek’s Job Content Questionnaire. Saliva samples were gathered during 8~9 am and 5~6 pm, and salivary cortisol levels were analysed by radioimmunoassay. Results: After adjusting several variables which could effect cortisol secretion including job stress, among the higher RHR group morning salivary cortisol level was increased (β=60.32, S.E.=26.35, p=0.0266), afternoon salivary cortisol level was decreased (β=-7.43, S.E.=29.73, p=0.8044), and salivary cortisol level difference between morning and afternoon was increased (β=72.10, SE=35.50, p=0.0509). Conclusions: As physical workload increases morning cortisol level, which is caused by the effect of arousal, and decreases afternoon cortisol level, which is caused by exhaustion, physical workload enlarges the width of diurnal cortisol variance. Therefore, physical exhaustion due to excessive workload could have adverse effects on the neuroendocrine system.

Increased beclomethasone-induced vasoconstriction in women with posttraumatic stress disorder

It has been hypothesized that patients with posttraumatic stress disorder (PTSD) show increased glucocorticoid sensitivity. The study tested beclomethasone-induced vasoconstriction (BIV), a measure of peripheral glucocorticoid sensitivity, in women with PTSD. A case-control design was employed in 33 PTSD patients and 33 healthy controls. BIV was tested using beclomethasone dipropionate (1-100 micro g/ml). Vasoconstriction was assessed after 15-18 h. Waking and afternoon salivary cortisol concentrations were measured. BIV ratings were significantly increased in PTSD at beclomethasone concentrations from 10-100 micro g/ml. Salivary cortisol concentrations did not differ between groups or correlate with BIV. Preliminary evidence has been found for increased peripheral glucocorticoid sensitivity in PTSD. Further study is required to replicate this finding and assess its relationship to the pathophysiology of the disorder.

Salivary cortisol as a predictor of socioemotional adjustment during kindergarten: a prospective study.

This study, based on a sample of 172 children, examined the relation between average afternoon salivary cortisol levels measured at home at age 4.5 years and socioemotional adjustment a year and a half later, as reported by mothers, fathers, and teachers. Cortisol levels were hypothesized to be positively associated with withdrawal-type behaviors (e.g., internalizing, social wariness) and inversely related to approach-type behaviors, both negative and positive (e.g., externalizing, school engagement). Higher cortisol levels at age 4.5 predicted more internalizing behavior and social wariness as reported by teachers and mothers, although child gender moderated the relation between cortisol and mother report measures. An inverse relation was found between boys' cortisol levels and father report of externalizing behavior. A marginal inverse relation was found between child cortisol levels and teacher report of school engagement. Behavior assessed concurrently with cortisol collection did not account for the prospective relations observed,suggesting that cortisol adds uniquely to an understanding of behavioral development.

Salivary Cortisol Levels and Work-Related Stress Among Emergency Department Nurses

The objective of this study was to assess and compare the self-perceived work-related stress of emergency department (ED) and general ward (GW) nurses and to assess the relationship between self-perceived stress and salivary cortisol levels in these groups of nurses. Seventy-three female ED (n = 23) and GW (n = 50) nurses from a general hospital completed a self-administered questionnaire. A modified mental health professional stress scale (PSS) was used to measure self-perceived work-related stress. Salivary samples were collected at the start and end of morning shiftwork. An enzyme-linked immunosorbent assay method was used to determine the salivary cortisol concentration (nmol/L). ED nurses perceived that nursing was more stressful (mean, 1.58; 95% confidence interval [CI], 1.35 to 1.81) than did GW nurses (mean, 1.30; 95% CI, 1.18 to 1.40). On the PSS subscales, scores of organizational structure and process, lack of resources, and conflict with other professionals were higher in ED nurses (all P < 0.01). The morning cortisol was significantly lower in ED (geometric mean, 9.10; 95% CI, 6.62 to 12.42 nmol/L) than in GW (geometric mean, 15.45; 95% CI, 11.86 to 20.14 nmol/L) nurses. Log morning salivary cortisol was negatively correlated with PSS (r = -0.255), scores of organizational structure and process, and conflict with other professionals (all P < 0.05). The difference between morning and afternoon cortisol concentration in ED nurses (geometric mean, 6.35; 95% CI 4.14 to 9.93 nmol/L) was lower than in GW nurses (geometric mean, 12.42; 95% CI, 9.38 to 16.28 nmol/L). The log value of the difference correlated marginally with PSS (r = -0.21, P = 0.07) and significantly with scores of organizational structure and process, lack of resources, and conflict with other professionals (all P < 0.05). There was no difference between the two groups in afternoon salivary cortisol level. ED nurses perceived more stress compared with GW nurses. Morning salivary cortisol concentration is better correlated with PSS compared with the morning-afternoon salivary cortisol difference. The result raises the possibility of using a single morning salivary cortisol sample to reflect self-perceived stress.