Physiological Measures Of Stress Research Articles

The feasibility of using real-time, objective measurements of physiological stress among law enforcement officers in Dallas, Texas

Purpose Law enforcement officers (LEOs) suffer from premature mortality, intentional and unintentional injury, suicide and are at an increased risk for several non-communicable disease outcomes including cardiovascular disease and several cancers, compared to those employed in other occupations. Repeated exposure to stressful and traumatic stimuli is a possible mechanism driving these adverse health outcomes among LEOs. To better identify the sources of these health problems, the purpose of this paper is to determine the feasibility of conducting a cohort study using physiological measures of stress (e.g. heart rate) with LEOs; perceptions of the FitBit device, including LEO buy-in and attitudes associated with the protocol. Design/methodology/approach Data were collected from ten recent graduates of the Dallas Police Training Academy. Findings Results suggest that officer buy-in and protocol compliance was high. Officers were eager to participate in this study, and completion of weekly surveys was 100 percent. Minute-level missing data from wearable devices was relatively low (25 percent), and 90 percent of participants wore the FitBit devices on more than 90 percent of study days. Originality/value Results from this study suggest that wearable physiological devices can be effectively used in law enforcement populations to measure stress.

Changes in tinnitus and physiological biomarkers of stress in response to short-term broadband noise and sounds of nature

BackgroundTinnitus is the perception of sound when no external sound source is present. In some cases, this perception coincides with, or results in, stress. Tinnitus-related distress has been associated with increased levels of cortisol and elevated levels of sympathetic tone. Our primary hypothesis was that short-term sound exposure would reduce tinnitus perception and various physiological measures of stress. A secondary hypothesis was that a self-selected nature sound would reduce physiological markers of stress more than broadband noise. MethodsTwenty-one participants with constant bothersome tinnitus underwent an audiological assessment. Measurements of blood pressure, heart rate, salivary cortisol and cortisone concentrations, and tinnitus ratings were carried out three times: prior to and, in a counterbalance order, after 30 min of broadband noise and after 30 min of a self-selected nature sound (from: ocean waves, stream, rain or shower sounds). ResultsFindings revealed significant reductions in blood pressure measurements following broadband noise. None of the other stress measures demonstrated a statistically significant change. Both broadband noise and nature sounds elicited significant improvements in ratings of tinnitus. ConclusionsWhile both sound types had a positive impact on many dimensions of tinnitus, only the broadband noise was associated with a reduction in blood pressure. These results are consistent with a complex interaction between sound and tinnitus and suggest a multifactorial basis to sound therapy that includes a reduction in arousal.

Individual Differences in the Association Between Subjective Stress and Heart Rate Are Related to Psychological and Physical Well-Being

The physiological response to stress is intertwined with, but distinct from, the subjective feeling of stress, although both systems must work in concert to enable adaptive responses. We investigated 1,065 participants from the Midlife in the United States 2 study who completed a self-report battery and a stress-induction procedure while physiological and self-report measures of stress were recorded. Individual differences in the association between heart rate and self-reported stress were analyzed in relation to measures that reflect psychological well-being (self-report measures of well-being, anxiety, depression), denial coping, and physical well-being (proinflammatory biomarkers interleukin-6 and C-reactive protein). The within-participants association between heart rate and self-reported stress was significantly related to higher psychological well-being, fewer depressive symptoms, lower trait anxiety, less use of denial coping, and lower levels of proinflammatory biomarkers. Our results highlight the importance of studying individual differences in coherence between physiological measures and subjective mental states in relation to well-being.

The Acute Effects of Yoga on Physiological and Psychological Measures of Stress in College Students

College students commonly report high levels of stress due to academic pressures and social challenges. Subsequently, the use of yoga as a form of stress-relief has become increasingly popular among college students. PURPOSE: to determine the acute effects of yoga on physiological and psychological measures of stress in college students. METHODS: Participants (n=20, 16 female) were initially assessed for baseline proxy measures of psychological and physiological stress. Psychological stress was assessed via the Positive and Negative Affect Schedule (PANAS) Questionnaire. Physiological stress was assessed by outfitting each subject with a five-lead EKG Holter monitor to measure heart rate variability (HRV). HRV was determined as the time interval between R-R waves (ms). Once baseline levels of stress were recorded, participants then completed a 20 min video of a Vinyasa Flow Sun Salutation yoga practice, while supervised by a certified yoga instructor. After the conclusion of the yoga session, participants’ post-baseline stress levels were re-assessed via PANAS and HRV. RESULTS: There was a statistically significant increase in positive affect scores from pre (26.7 ± 8.79) to post (31.0 ± 8.47), p = 0.004. The mean increase in positive affect scores (4.30 ± 5.9) indicated a moderate effect size, d = 0.73. There was a statistically significant decrease in negative affect scores from pre (15.95 ± 4.74) to post (11.35 ± 4.21), p < 0.001. The mean decrease in negative affect scores (4.6 ± 3.76) indicated a large effect size, d = 1.22. —There was a statistically significant increase in HRV scores from pre (665.5 ± 104.36 ms) to post (924.3 ± 122.98 ms), p < 0.001. The mean increase in HRV score (258.8 ± 102.32 ms) indicated a large effect size, d = 2.52. CONCLUSIONS: The results of this study indicated that a 20 min yoga practice resulted in a significant improvement in positive affect scores (16%), a significant decrease in negative affect scores (29%), and a significant improvement in HRV (39%), all indicative of a reduction in psychological and physiological measures of stress levels.

Determining the effect of stress on analytical skills performance in digital decision games towards an unobtrusive measure of experienced stress in gameplay scenarios

This study aims to develop an unobtrusive measure for experienced stress in a digital serious gaming environment involving decision making in crisis management, using only in-game measures in a digital decision game called the Mayor Game. Research has shown that stress has an influence on a decision-maker's behavior, and also on the learning experience in training scenarios. Being able to assess unobtrusively the level of stress experienced would allow manipulation of the game so as to improve the learning experience. An experiment was conducted with two conditions, one paced and one non-paced. In the paced condition, participants were exposed to in-game changes that aimed to induce stress by creating information overload, uncertainty and time pressure. While pacing caused differences between the conditions with respect to in-game performance for analytical skills, several simple unobtrusive in-game measures were not consistent enough to serve as indicators for experienced stress. Further, physiological measurements of stress did not show significant differences between the conditions, indicating that the employed methods to induce stress did not work sufficiently. These results call for testing of more sophisticated methodologies to unobtrusively assess experienced stress in the given type of serious game.

Colony size affects nestling immune function: a cross-fostering experiment in a colonial waterbird

Elevated transmission rate of pathogens and parasites is considered one of the major costs of sociality in birds. However, greater risk of infection in colonial birds might be compensated by specific immune adaptations. Here, we predicted that nestlings raised in larger colonies should invest more in their immune function. To test this hypothesis, we manipulated colony size and conduced cross-fostering experiment in a colonial waterbird, the common tern Sterna hirundo. Establishment of different size colonies under uniform environmental conditions was induced by providing large and small patches of attractive nesting area for terns (floating rafts). Then, pairs of clutches were swapped between large and small tern colonies, and skin-swelling response to phytohaemagglutinin (PHA) was assessed for nestlings from experimental and control broods. Contrary to our expectations, we found a negative effect of foster colony size on nestling PHA response (nestlings raised in the larger colony had lower PHA response). In addition, nestling PHA response correlated negatively with heterophil/lymphocyte ratio used as a measure of physiological stress. This suggested that low PHA response of nestlings raised in the larger colony could be mediated by an elevated level of social stress. We suggest that depression of immune function via social stress may constitute a strong selective pressure against large colony size in the common tern, and possibly in other colonial species. We also recommend that this largely overlooked cost of sociality should be considered in the further studies on the evolution and ecology of avian coloniality.

Chronic Effects of Euphytose® on Psychological and Physiological Measures of Stress

Chronic Effects of Euphytose® on Psychological and Physiological Measures of Stress

Combining driving simulator and physiological sensor data in a latent variable model to incorporate the effect of stress in car-following behaviour

Car-following models, which are used to predict the acceleration-deceleration decisions of drivers in the presence of a closely spaced lead vehicle, are critical components of traffic microsimulation tools and useful for safety evaluation. Existing car-following models primarily account for the effects of surrounding traffic conditions on a driver’s decision to accelerate or decelerate. However, research in human factors and safety has demonstrated that driving decisions are also significantly affected by individuals’ characteristics and their emotional states like stress, fatigue, etc. This motivates us to develop a car-following model where we explicitly account for the stress level of the driver and quantify its impact on acceleration-deceleration decisions. An extension of the GM stimulus-response model framework is proposed in this regard, where stress is treated as a latent (unobserved) variable, while the specification also accounts for the effects of drivers’ sociodemographic characteristics. The proposed hybrid models are calibrated using data collected with the University of Leeds Driving Simulator where participants are deliberately subjected to stress in the form of aggressive surrounding vehicles, slow leaders and/or time pressure while driving in a motorway setting. Alongside commonly used variables, physiological measures of stress (i.e. heart rate, blood volume pulse, skin conductance) are collected with a non-intrusive wristband. These measurements are used as indicators of the latent stress level in a hybrid model framework and the model parameters are estimated using Maximum Likelihood Technique. Estimation results indicate that car-following behaviour is significantly influenced by stress alongside speed, headway and drivers’ characteristics. The findings can be used to improve the fidelity of simulation tools and designing interventions to improve safety.

The efficacy of stress reappraisal interventions on stress responsivity: A meta-analysis and systematic review of existing evidence.

BackgroundThe beliefs we hold about stress play an important role in coping with stressors. Various theoretical frameworks of stress point to the efficacy of reframing stress-related information through brief reappraisal interventions in order to promote adaptive coping.PurposeThe goal of the current meta-analysis and systematic review is to substantiate the efficacy of reappraisal interventions on stress responsivity compared to control conditions. Differences in experimental methodologies (e.g., type of stressor used, timing of reappraisal intervention, and content of intervention instructions) will be examined to further delineate their effects on intervention outcomes.MethodsThe literature searches were conducted on May 16, 2018 using PsycINFO, ProQuest Dissertations and Theses, and PILOTS databases with no date restriction. The search terms included stress, reframing, reappraisal, mindset and reconceptualising. A total of 14 articles with 36 independent samples were included in the meta-analysis, while 22 articles with 46 independent samples were included in the systematic review. Random-effects model was used to test the null hypothesis using two-tailed significance testing. Fisher’s Z value was reported for each corresponding test. Heterogeneity tests are reported via Cochran’s Q-statistics.ResultsFindings from both the meta-analysis and systematic review revealed that overall, reappraisal interventions are effective in attenuating subjective responsivity to stress. Standard differences in means across groups are 0.429 (SE = 0.185, 95% CI = 0.067 to 0.791; z = 2.320, p = .020). However, reappraisal intervention groups did not outperform control groups on measures of physiological stress, with standard differences of -0.084 (SE = 0.135, 95% CI = -0.349 to 0.180; z = -0.627, p = .531). Moderator analysis revealed heterogeneous effects suggesting large variability in findings.ConclusionsOn one hand, findings may suggest a promising avenue for the effective management of self-reported stress and optimization of stress responses. However, more research is needed to better elucidate the effects, if any, of reappraisal interventions on stress physiology. Implications for the use of reappraisal interventions on stress optimization are discussed in the context of theoretical frameworks and considerations for future studies.

Subjective and physiological stress measurement in a multiple sclerosis sample and the relation with executive functions performance.

In multiple sclerosis (MS), hypothalamic-pituitary-adrenal (HPA) axis functioning may be dysregulated due to the high cortisol levels involved in the disease activity. HPA axis dysregulation can affect cognitive performance, including executive functions. This study aimed to evaluate hair cortisol concentration and perceived stress as well as verify the association with the performance of executive function in both individuals diagnosed with MS and control individuals. Hair cortisol concentration and perceived stress were evaluated and their association with the performance of healthy individuals (n = 33) and those with MS (n = 64), most of them with remitting-relapsing multiple sclerosis (RRMS) assessed using the Expanded Disability Status Scale (EDSS). Instruments that were employed to measure perceived stress and health aspects included the Behavioral Assessment Dysexecutive Syndrome, Wisconsin Card Sorting Test, Stroop Test, and Perceived Stress Scale. No significant statistical difference was found in the comparison of means among the groups; however, an association was found when using statistical correlation tests between cortisol and cognitive performance in the clinical group (r = 0.31, p = 0.10). Further, an absence of correlations with perceived stress measure was noted. It was possible to observe interaction between group factors and low level of cortisol and problem-solving/cognitive flexibility in the MS group. The results indicated that stress measures used in the present study seem to influence the performance of inhibitory control and problem-solving/cognitive flexibility, the latter with low levels of cortisol in individuals with MS. We suggest studies that examine different measures of physiological stress and characteristics of the disease such as more time of stress.

Differences in development of neurocognitive functions in premature and healthy full-term infants

This study had two specific objectives, 1) to investigate the impact of being on-call on overnight heart rate variability during sleep and; 2) to examine whether being on-call overnight impacted next-day salivary cortisol concentrations.Data are reported from three within-subject laboratory studies (n = 24 in each study) that assessed varying on-call conditions. Healthy male participants (n = 72 total) completed a four-night laboratory protocol, comprising an adaptation night, a control night, and two counterbalanced on-call nights with varying on-call conditions. These on-call conditions were designed to determine the impact of, Study 1: the likelihood of receiving a call (definitely, maybe), Study 2: task stress (high-stress, low-stress), and Study 3: chance of missing the alarm (high-chance, low-chance), on measures of physiological stress. Overnight heart rate variability (HRV) (during sleep) was measured using two-lead electrocardiography, and time- and frequency-domain variables were analysed. Saliva samples were collected at 15-min time intervals from 0700-0800 h to determine cortisol awakening response outcomes and at four daily time points (0930 h, 1230 h, 1430 h, and 1730 h) to assess diurnal cortisol profiles.There were few differences in HRV measures during sleep across all three studies. The only exception was in Study 1 where the standard deviation of the time interval between consecutive heartbeats and the root mean square of consecutive differences between heartbeats were lower across all sleep stages in the definitely condition, when compared to control. Across all three studies, being on-call overnight also had little impact on next-day cortisol awakening response (CAR), with the exception of Study 2 where the 1) CAR area under the curve with respect to increase was blunted in the high-stress condition, compared to the control and low-stress conditions and, 2) CAR reactivity was higher in low-stress condition, compared with the high-stress condition. In Study 1, diurnal cortisol area under the curve with respect to ground was lower in the on-call conditions (definitely and maybe) when compared to control. There were no differences in diurnal cortisol measures in Study 3.This is the first study to investigate how different aspects of being on-call affect physiological stress responses. Overall, relatively little differences in measures of overnight heart rate variability and next-day cortisol response were recorded in all three studies. Further research utilising real on-call work tasks, not just on-call expectations (as in the current study) will help determine the impact of on-call work on the physiological stress response.

The psychometric properties and temporal dynamics of subjective stress, retrospectively assessed by different informants and questionnaires, and hair cortisol concentrations

To date, there is only scarce evidence for a considerable association of subjective and objective stress measures, which might be attributable to method bias (e.g., confounding) and/or asynchrony of their temporal changes. To validate different subjective stress measures by a physiological measure of long-term stress (hair cortisol concentrations; HCC), 37 heterosexual couples (N = 74) completed a 12-week internet-based assessment protocol comprised of a weekly hassle scale (WHS; once per week), a perceived stress scale (PSS; once per month), and a chronic stress scale (TICS; once after three months). Partners provided vicarious stress ratings. When averaged across time, self-reported WHS significantly predicted HCC (r = 0.27), whereas the PSS and TICS did not (r < 0.22). Dynamic factor analysis (i.e., state-space modelling) confirmed that WHS was the most valid indicator of subjective stress, explaining up to 16% of the variance in HCC (r = 0.37) with a time lag of ~4 weeks. This temporally delayed effect of subjective stress is consistent with the presumed retrospective character of HCC, but also suggests that the majority of variance in hair cortisol is attributable to other causes than subjective stress such as individual disposition to display increased adrenocortical activity.

Evolution of heterophil/lymphocyte ratios in response to ecological and life-history traits: A comparative analysis across the avian tree of life.

Lymphocytes and heterophils are the two most abundant leucocyte types, which play a major role in adaptive and innate immune defence, respectively. The ratio of heterophils to lymphocytes (H/L ratio) may reflect a readiness to cope with infection through injury (via heterophils) rather than with a communicable disease (via lymphocytes). Since elevated H/L ratio constitutes a corticosterone-mediated response to external stressors, this trait is generally acknowledged as the robust measure of physiological stress in vertebrates. Here, I hypothesized that baseline H/L ratios of birds (as measured under normal physiological function) could be an important evolutionary trait shaped by species' ecology and life history. I predicted that H/L ratios should be determined by traits related to pathogen exposure (migratoriness, sociality, breeding latitude) and trade-offs between investment in reproduction (clutch size) and self-maintenance (longevity). I compiled published data on leucocyte profiles for nearly 250 bird species representing over half of all extant avian orders and nearly 30% of all extant avian families. Phylogenetically informed comparative methods were used to assess evolutionary associations of H/L ratios with ecological and life-history traits across the avian tree of life. Relatively strong phylogenetic signal and phylogenetic autocorrelation in avian H/L ratios indicated that most diversification in this trait occurred relatively early in bird radiation. Fluctuating selection and drift were identified as the major forces responsible for the evolution of H/L ratios in birds, while low H/L ratios were identified as an ancestral state in birds. Finally, phylogenetically informed Bayesian models showed that H/L ratios correlated negatively with longevity and positively with sociality and breeding latitude. This study was the first to describe the patterns of avian H/L ratio evolution in a broad phylogenetic framework. The results indicate that H/L ratios should not be merely recognized as a proxy for the intraspecific variation in physiological stress, but also as an important evolutionary trait, which probably have adaptive significance visible in a wider phylogenetic perspective.

Validation of the Teacher Stress Inventory (TSI) in a multicultural context: The SABPA study

The aim of this study was to validate the Teacher Stress Inventory (TSI) for use in a South African context. The process of scale validation also sheds significant light on this culturally diverse group of participants’ levels of psychological well-being and physical health, and its association with the level of stress that teachers reported. Using a cross-sectional survey design, Caucasian ( n = 209) and African ( n = 200) educators’ subsiding in the North-West Province of South Africa, completed the TSI, together with a number of self-report and physiological measures of stress and well-being. In contrast to the five factors of the TSI identified in US samples, statistical analysis yielded a two-factor model (i.e. General circumstance-related stress and Learner-related stress ) with satisfactory reliability indices. Significant correlation with measures of psychological and physiological health also reflected positively on the criterion-related validity of the scale. The TSI proved to be a useful, brief self-report questionnaire for the assessment of teacher stress in this cohort of South African teachers. Keywords: psychological well-being; reliability; South African context; stress; Teacher Stress Inventory (TSI); validity

Positive verbal feedback about task performance is related with adaptive physiological responses: An experimental study of the effort-reward imbalance stress model.

Effort-reward imbalance in the workplace has been related with poor mental and physical health and a variety of negative organisational outcomes including increased rates of absenteeism, presentism, and job turnover, but the model has rarely been assessed using experimental designs. Female participants (N = 90) were randomly assigned to positive verbal feedback and no verbal feedback conditions. Within a simulated office environment, all participants were under time-pressure to successfully complete computer-based tasks in order to gain remuneration. Positive verbal feedback about task performance was provided to improve the aspect of 'esteem reward' (while keeping effort constant) using a mixed within-between subjects design. Psychological, behavioural (task performance), and physiological (heart rate variability, salivary alpha amylase) measures assessed the impact of the positive verbal feedback. Participants receiving the esteem manipulation did not self-report increased rewards, but performed moderately better on the task, and had more adaptive physiological reactivity in the high reward versus the standard condition. Similar to recent research our findings highlight the importance of concurrent assessments of both self-reports and physiological measures of stress, and suggest that positive verbal feedback about work performance can elicit adaptive physiological responses and may also positively influence task efficacy.

An online mindfulness-based program is effective in improving affect, over-commitment, optimism and mucosal immunity

Previous studies have demonstrated mindfulness-based programs are effective in reducing workplace stress; however, few have investigated the effectiveness of online mindfulness-based programs. Physiological measures are also underutilised when examining the efficacy of these programs. Therefore, we assessed the efficacy of an online mindfulness-based program on both short-term and more enduring aspects of psychological and physiological measures of stress and ill-health. Participants (N = 22) completed an 8-week online mindfulness-based program. Immediately before and after a mindfulness session, participants completed questionnaires to assess the short-term effects on mood and state anxiety and provided saliva samples to assess salivary alpha amylase (sAA) concentrations. Additionally, pre and post the 8-week intervention, participants completed questionnaires assessing workplace stress, over-commitment, work engagement, dispositional mindfulness and personal resources. Saliva samples were collected to measure the cortisol awakening response, sAA awakening response and secretory immunoglobulin A (sIgA). Our findings demonstrate that online mindfulness-based programs induce short-term improvements in fatigue and anxiety in employees. Additionally, we also report a decrease in over-commitment and increases in optimism and mucosal immunity (sIgA) following the program.

Aerobic physical activity and salivary cortisol levels among women with a history of breast cancer

BackgroundPhysical activity (PA) helps reduce cancer-related symptoms and improves overall functioning for women with and without a history of breast cancer (BC). Few researchers have examined the associations between PA and physiological stress measures. The aim of this study was to determine whether aerobic PA was associated with diurnal and reactive cortisol patterns, and whether these associations differed for women with and without a history of BC. MethodsParticipants were 25 women with a history of BC and 23 women without a history of BC who self-reported aerobic PA frequency. To assess diurnal cortisol patterns, participants provided five saliva samples collected on two consecutive days at the following times: upon awakening, 30 min after waking, 12 PM, 4 PM, and 9 PM. To measure reactive cortisol patterns, participants provided seven saliva samples collected before, during, and after doing the Trier Social Stress Test. ResultsCortisol patterns differed statistically based on women’s cancer history, whereby women without a history of BC had significantly higher overall cortisol reactivity to an acute stressor, and a marginally significant (p = .05) cancer experience by aerobic PA interaction was observed when analyzing diurnal cortisol data. ConclusionsFindings suggest that PA may not have the same effect on women with and without a history of BC.

Physiological stress measures in preschool children and their relationship with body composition and behavioral problems.

The relationship between physiological stress measures and body composition or behavioral problems in older children remains controversial, and data in young children are lacking. The aim of the study was to investigate this relationship in predominantly healthy preschool children. Physiological stress measures were assessed using diurnal salivary alpha-amylase (sAA) and salivary cortisol, nail cortisol and parasympathetic activation (PNS) by overnight heart rate variability, and body composition (body mass index, skinfold thickness) and behavior problems (using the Strengths and Difficulties Questionnaire) in 324 children aged 2-6years of the SPLASHY study. Parasympathetic nervous system was inversely related to body fat, to emotional, and to peer problems. Diurnal sAA was related to hyperactivity problems and moderated the relationship of cortisol and hyperactivity problems. Cortisol was not related to any other health problems. The relationship of PNS with body composition and behavioral problems might highlight the protective role of the parasympathetic system early in life.

229. Hair cortisol concentration and reported anxiety are elevated in preeclampsia

Introduction While some studies argue that maternal stress during pregnancy is a risk-factor for preeclampsia (PE), other studies do not support this hypothesis. These studies did not incorporated physiological stress measures and recall bias may explain their results. Objective To investigate whether maternal stress during pregnancy, as measured by questionnaires and cortisol concentrations in hair, differ between a group of women with early onset PE, late onset PE and uncomplicated pregnancies. Methods This multicentre case-controlled study included women with early-onset PE ( 34 wks gestation; n = 18), and uncomplicated pregnancies (n = 26). At admission in the hospital (early-onset PE and late-onset PE), or at term pregnancy (controls), mothers filled out stress and anxiety questionnaires. Participants also donated a strand of hair at admission, not influenced by corticosteroid administration. The average hair growth rate is 1 cm a month, with the hair closest to the scalp representing the most recent part of pregnancy. Cortisol concentration in hair were analyzed in three periods: 3 months before conception (preconception), 0–3 months of pregnancy (1st trimester) and 3–6 months pregnancy (2nd trimester). Results ANOVA’s showed that reported anxiety levels were higher in women with preeclampsia compared to the controls (p Discussion These results indicate that measures of psychosocial anxiety and physiological stress differ between early-onset PE, comparing to late-onset PE and uncomplicated pregnancies. Late-onset PE might be associated with a higher level of preconceptional cortisol concentration, although these results were underpowered, cortisol concentrations may be utilized to assess the differentiation between early-onset and late-onset PE.

A Brief Report on the 2.4-Year Test-Retest Agreement of Morning Cortisol and Anxiety in Boys with Autism Spectrum Disorder

Children with Autism Spectrum Disorder (ASD) also often suffer from elevated stress and anxiety. These states can be measured via reports of behaviour (from self or others) or from physiological measures of stress, including the symptoms of Generalised Anxiety Disorder (GAD) and salivary cortisol, respectively. The use of these measures assumes a degree of reliability over time so that data from a specific period may be generalised to other periods. To measure the test-retest reliability of salivary cortisol and self-ratings of GAD in 27 high-functioning boys with ASD (M age = 12.1 yr., SD = 2.8 yr), samples were collected a mean of 2.4 yr. (SD = 0.5 yr) apart and analysed to test for the presence of a significant correlation within each variable over time. Results indicated that, although the concentrations of salivary cortisol increased over the period of the study, there was a significant correlation between the two measures of cortisol. GAD scores also showed a significant correlation over the period of the study. These findings suggest that both GAD and salivary cortisol data collected from boys with ASD may be reasonably inferred to represent fairly stable phenomena over time in research and clinical settings.