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2.
J Acoust Soc Am ; 152(5): 2588, 2022 11.
Article in English | MEDLINE | ID: mdl-36456287

ABSTRACT

Descriptions of the acoustic characteristics of Swedish voiceless fricatives are scarce and are limited to static measures derived from the speech of a small number of speakers. The current study provides an updated acoustic description of the static (spectral, temporal, and intensity) characteristics of word-initial voiceless fricatives in Central Standard Swedish. In addition, temporal variation of spectral centre of gravity is modelled using a generalized additive mixed model. Results show that fricatives were differentiated in terms of spectral properties, duration, and intensity level, such that sibilant fricatives were generally longer and more intense than non-sibilant fricatives. Spectral centre of gravity differentiated between all places of articulation apart from labio-dental /f/. Gender differences were found for centre of gravity in /s/ but overall, sex/gender differences were small. Dynamic analyses revealed differences in curvature as well as overall level of spectral centre of gravity across the duration of the fricative, associated with place of articulation and mediated by vowel context, fricative duration, and speaker specific patterns. The results from the present study are valuable for future cross-linguistic research, and as reference for investigations concerning children's acquisition of Swedish voiceless fricatives.


Subject(s)
Language , Linguistics , Child , Humans , Sweden , Speech , Acoustics
3.
Healthcare (Basel) ; 10(6)2022 May 25.
Article in English | MEDLINE | ID: mdl-35742030

ABSTRACT

The wellbeing benefits of engaging in a nature-based programme, delivered by the Voluntary, Community and Social Enterprise sector, were examined in this study. Prior to attending The Conservation Volunteers' Green Gym™, attendees (n = 892) completed demographics, health characteristics and the Warwick Edinburgh Mental Wellbeing Short-Form Scale. Attendees (n = 253, 28.4%) provided a measure on average 4.5 months later. There were significant increases in wellbeing after engaging in Green Gym, with the greatest increases in those who had the lowest starting levels of wellbeing. Wellbeing increases were sustained on average 8.5 months and 13 months later in those providing a follow up measure (n = 92, n = 40, respectively). Attendees who continued to engage in Green Gym but not provide follow up data (n = 318, 35.7%) tended to be more deprived, female and self-report a health condition. Attendees who did not continue to engage in Green Gym (n = 321, 36.0%) tended to be less deprived and younger. These findings provide evidence of the wellbeing benefits of community nature-based activities and social ('green') prescribing initiatives and indicate that Green Gym targets some groups most in need.

4.
Healthcare (Basel) ; 9(6)2021 Jun 12.
Article in English | MEDLINE | ID: mdl-34204685

ABSTRACT

There are known links between the hypothalamic-pituitary-adrenal (HPA) axis and systems responsible for regulating posture. Our aim was to explore directly, for the first time, whether an aspect of circadian HPA axis activity (the cortisol awakening response: CAR) was associated with greater visual dependency in postural control. For measurement of the CAR, electronically monitored saliva samples were collected by participants following morning awakening in their home environment. On the afternoons of the same days, postural sway was measured in the laboratory by exposing participants to static (control) and moving visual stimuli whilst standing still and upright on a force platform. Visual dependence was assessed as the increase in postural sway (path length) during exposure to the moving compared with the static condition. The 44 measurement days were derived from four days for each of eleven healthy participants (mean ± SD age: 51.18 ± 3.3 years). As expected, postural sway was greater when exposed to moving versus static cues. Mixed regression modelling showed that participants with smaller four day average CARs had greater deterioration in postural sway when presented with moving stimuli. These data are the first to document associations between the CAR and visual dependency in postural sway.

5.
Int J Psychophysiol ; 158: 27-33, 2020 12.
Article in English | MEDLINE | ID: mdl-32979414

ABSTRACT

The cortisol awakening response (CAR) is associated with various aspects of cognition, including executive function, in older adult and clinical samples. However, the association between these variables in the healthy functioning population is not well understood due to the limited number of appropriately controlled studies. This study explored the association between the CAR and a set shifting index of executive function in 55 (44 females) healthy participants aged 20.2 ± 3.0 years. Notoriously, assessment of the CAR from self-collected saliva samples within the domestic setting is subject to sample timing error, so electronic monitoring of both awakening and sampling times were employed. Participants attended the laboratory in the afternoon of CAR assessment for testing on the Attention Switching Task of the CANTAB neuropsychological testing battery. A positive association was found between CAR magnitude and attention-switching performance in the afternoon of the same day. This was independent of known relevant CAR covariates, but only evident in CAR data collected without delay exceeding 8 min post-awakening. These findings offer insight into a potential role for the CAR in modulating cognitive functions associated with the pre-frontal cortex.


Subject(s)
Executive Function , Hydrocortisone , Aged , Circadian Rhythm , Female , Humans , Saliva , Time Factors , Wakefulness , Young Adult
6.
Psychoneuroendocrinology ; 74: 380-386, 2016 12.
Article in English | MEDLINE | ID: mdl-27750142

ABSTRACT

The cortisol awakening response (CAR) is typically measured in the domestic setting. Moderate sample timing inaccuracy has been shown to result in erroneous CAR estimates and such inaccuracy has been shown partially to explain inconsistency in the CAR literature. The need for more reliable measurement of the CAR has recently been highlighted in expert consensus guidelines where it was pointed out that less than 6% of published studies provided electronic-monitoring of saliva sampling time in the post-awakening period. Analyses of a merged data-set of published studies from our laboratory are presented. To qualify for selection, both time of awakening and collection of the first sample must have been verified by electronic-monitoring and sampling commenced within 15min of awakening. Participants (n=128) were young (median age of 20 years) and healthy. Cortisol values were determined in the 45min post-awakening period on 215 sampling days. On 127days, delay between verified awakening and collection of the first sample was less than 3min ('no delay' group); on 45days there was a delay of 4-6min ('short delay' group); on 43days the delay was 7-15min ('moderate delay' group). Cortisol values for verified sampling times accurately mapped on to the typical post-awakening cortisol growth curve, regardless of whether sampling deviated from desired protocol timings. This provides support for incorporating rather than excluding delayed data (up to 15min) in CAR analyses. For this population the fitted cortisol growth curve equation predicted a mean cortisol awakening level of 6nmols/l (±1 for 95% CI) and a mean CAR rise of 6nmols/l (±2 for 95% CI). We also modelled the relationship between real delay and CAR magnitude, when the CAR is calculated erroneously by incorrectly assuming adherence to protocol time. Findings supported a curvilinear hypothesis in relation to effects of sample delay on the CAR. Short delays of 4-6min between awakening and commencement of saliva sampling resulted in an overestimated CAR. Moderate delays of 7-15min were associated with an underestimated CAR. Findings emphasize the need to employ electronic-monitoring of sampling accuracy when measuring the CAR in the domestic setting.


Subject(s)
Hydrocortisone/metabolism , Specimen Handling/standards , Adolescent , Adult , Circadian Rhythm/physiology , Female , Humans , Male , Saliva/chemistry , Time Factors , Young Adult
7.
Int J Psychophysiol ; 102: 12-17, 2016 04.
Article in English | MEDLINE | ID: mdl-26948137

ABSTRACT

Hair cortisol concentration (HCC) provides a retrospective measure of long-term (i.e. over a period of months) cortisol secretion and has been shown to be elevated in relation to chronic stress conditions. However associations in healthy participants with subjective ill-being are less clear and associations with well-being have not been explored. The current study examined HCC in relation to independent comprehensive measures of ill-being (stress, depression, anxiety) and well-being (subjective happiness, life satisfaction, psychological well-being) in healthy young and old females (mean±SD: 19.5±2.2years and 78.6±6.7years respectively, total N=115). The data supported evidence of increased total cortisol secretion with increased age. No association between ill-being and HCC was found in either the young or older group of participants. A positive association between HCC and well-being was found in the older participant group which was independent of ill-being and potential confounds. These findings do not support associations between HCC and ill-being in healthy young or old females. However the results suggest that HCC is able to distinguish levels of well-being in healthy older females.


Subject(s)
Aging , Hair/chemistry , Hydrocortisone/metabolism , Mood Disorders/metabolism , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Female , Happiness , Humans , Mood Disorders/psychology , Principal Component Analysis , Self Report , Young Adult
8.
Stress ; 19(2): 260-3, 2016.
Article in English | MEDLINE | ID: mdl-26809638

ABSTRACT

We report the relationship between patterns of post-awakening salivary melatonin and cortisol secretion in healthy participants (n = 51; mean age 21.6 ± 5.0 years). Saliva samples were collected within the domestic setting, at 0-, 15-, 30-, and 45-min post-awakening on 2 consecutive typical weekdays. Analyses were undertaken on data with electronically verified sample timing accuracy (<5-min delay between awakening and the start of saliva sampling). Melatonin secretion declined linearly by an average of 29% within the first 45-min post-awakening. In contrast, there was a marked 112% surge in cortisol, characteristic of the cortisol awakening response. No day differences in melatonin or cortisol secretion were observed but melatonin concentrations were lower with later awakening. Despite contrasting post-awakening changes in these hormones, there was a lack of relationship between overall levels or patterns of melatonin and cortisol during this period.


Subject(s)
Circadian Rhythm/physiology , Hydrocortisone/analysis , Melatonin/analysis , Adolescent , Adult , Female , Healthy Volunteers , Humans , Male , Saliva/chemistry , Young Adult
9.
Stress ; 18(6): 616-21, 2015.
Article in English | MEDLINE | ID: mdl-26382884

ABSTRACT

A relationship between individual differences in trait estimates of the cortisol-awakening response (CAR) and indices of executive function (EF) has been reported. However, it is difficult to determine causality from such studies. The aim of the present study was to capitalise upon state variation in both variables to seek stronger support for causality by examining daily co-variation. A 50 days researcher-participant case study was employed, ensuring careful adherence to the sampling protocol. A 24-year-old healthy male collected saliva samples and completed an attention-switching index of EF on the morning of each study day. Subsidiary control measures included wake time, sleep duration, morning fatigue, and amount of prior day exercise and alcohol consumption. As the CAR preceded daily measurement of EF, we hypothesised that, over time, a greater than average CAR would predict better than average EF. This was confirmed by mixed regression modelling of variation in cortisol concentrations, which indicated that the greater the increase in cortisol concentrations from 0 to 30 min post-awakening (CAR) the better was subsequent EF performance at 45 min post-awakening (t = 2.29, p = 0.024). This effect was independent of all potential confounding measures. Results are discussed in terms of implications for the understanding of the relationship between the CAR and the cognitive function, and the previously suggested role of the CAR in "boosting" an individual's performance for the day ahead.


Subject(s)
Circadian Rhythm/physiology , Executive Function/physiology , Hydrocortisone/analysis , Wakefulness/physiology , Cognition/physiology , Humans , Individuality , Male , Neuropsychological Tests , Saliva/chemistry , Young Adult
10.
Psychoneuroendocrinology ; 62: 200-3, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26318630

ABSTRACT

The cortisol awakening response (CAR) can be assessed from saliva samples collected at home, which confers ecological validity but lacks researcher oversight. Participant non-adherence to requested saliva sampling regimes leads to inaccurate CAR estimates. Moderate sampling delays of just 8 (5-15) min between awakening and commencement of saliva sampling are reported to result in over-estimated CAR magnitude and earlier peaking. This has been attributed to an observed 'latent' period in which cortisol secretion does not increase for up to 10-min after awakening. Replication of this finding is essential as the findings have considerable implications for CAR research. Healthy participants (n=26) collected saliva samples at 5-min intervals for 60min on 2 consecutive typical weekdays. Full electronic monitoring of awakening and sampling enabled exclusion of non-adherent data (i.e., delays of greater than 5min between awakening and collection of the first sample). In the 0-15min post awakening segment of the CAR a quadratic effect was observed, with no difference between the awakening and 5 and 10min samples. Moderate sampling delays will shift assessment of the CAR just sufficiently along the time axis to not impact upon measurement of the first sample but to remove the immediate post-awakening latent period from CAR estimates-whilst retaining later estimates of elevated cortisol secretion. The implication from these results is that accurate CAR measures can only be determined from data with strict adherence to commencement of saliva sampling following awakening.


Subject(s)
Hydrocortisone/analysis , Wakefulness/physiology , Adolescent , Adult , Circadian Rhythm/physiology , Female , Healthy Volunteers , Humans , Hypothalamo-Hypophyseal System/physiology , Male , Pituitary-Adrenal System/physiology , Saliva/chemistry , Specimen Handling , Time Factors , Young Adult
11.
Psychoneuroendocrinology ; 58: 141-51, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25988832

ABSTRACT

Indices of post awakening cortisol secretion (PACS), include the rise in cortisol (cortisol awakening response: CAR) and overall cortisol concentrations (e.g., area under the curve with reference to ground: AUCg) in the first 30-45 min. Both are commonly investigated in relation to psychosocial variables. Although sampling within the domestic setting is ecologically valid, participant non-adherence to the required timing protocol results in erroneous measurement of PACS and this may explain discrepancies in the literature linking these measures to trait well-being (TWB). We have previously shown that delays of little over 5 min (between awakening and the start of sampling) to result in erroneous CAR estimates. In this study, we report for the first time on the negative impact of sample timing inaccuracy (verified by electronic-monitoring) on the efficacy to detect significant relationships between PACS and TWB when measured in the domestic setting. Healthy females (N=49, 20.5±2.8 years) selected for differences in TWB collected saliva samples (S1-4) on 4 days at 0, 15, 30, 45 min post awakening, to determine PACS. Adherence to the sampling protocol was objectively monitored using a combination of electronic estimates of awakening (actigraphy) and sampling times (track caps). Relationships between PACS and TWB were found to depend on sample timing accuracy. Lower TWB was associated with higher post awakening cortisol AUCg in proportion to the mean sample timing accuracy (p<.005). There was no association between TWB and the CAR even taking into account sample timing accuracy. These results highlight the importance of careful electronic monitoring of participant adherence for measurement of PACS in the domestic setting. Mean sample timing inaccuracy, mainly associated with delays of >5 min between awakening and collection of sample 1 (median=8 min delay), negatively impacts on the sensitivity of analysis to detect associations between PACS and TWB.


Subject(s)
Affect/physiology , Circadian Rhythm/physiology , Hydrocortisone/analysis , Personal Satisfaction , Specimen Handling/methods , Actigraphy , Adolescent , Adult , Female , Humans , Saliva/chemistry , Salivation , Time Factors , Wakefulness/physiology , Young Adult
12.
Stress ; 18(2): 143-8, 2015.
Article in English | MEDLINE | ID: mdl-25758939

ABSTRACT

Insecure attachment style is associated with poor health outcomes. A proposed pathway implicates the hypothalamic-pituitary-adrenal axis (HPA-axis), dysregulation of which is associated with a wide range of mental and physical ill-health. However, data on stress reactivity in relation to attachment style is contradictory. This relationship was examined using the novel Trier Social Stress Test for groups (TSST-G): a group-based acute psychosocial stressor. Each participant, in the presence of other group members, individually performed public speaking and mental arithmetic tasks. Seventy-eight healthy young females (20.2 ± 3.2 years), in groups of up to six participants completed demographic information and the Vulnerable Attachment Style Questionnaire (VASQ), and were then exposed to the TSST-G. Physiological stress reactivity was assessed using salivary cortisol concentrations, measured on seven occasions at 10-min intervals. Vulnerable attachment predicted greater cortisol reactivity independent of age, smoking status, menstrual phase and body mass index. Supplementary analysis indicated that insecure anxious attachment style (high scores on the insecurity and proximity-seeking sub-scales of the VASQ) showed greater cortisol reactivity than participants with secure attachment style. Avoidant attachment style (high scores for insecurity and low scores for proximity seeking) was not significantly different from the secure attachment style. Attachment style was not associated with the timing of the cortisol peak or post-stress recovery in cortisol concentrations. These findings in healthy young females indicate subtle underlying changes in HPA axis function in relation to attachment style and may be important for future mental health and well-being.


Subject(s)
Anxiety/metabolism , Hydrocortisone/metabolism , Object Attachment , Stress, Psychological/metabolism , Adolescent , Adult , Body Mass Index , Female , Humans , Hypothalamo-Hypophyseal System/metabolism , Pituitary-Adrenal System/metabolism , Saliva/chemistry , Social Behavior , Speech , Surveys and Questionnaires , Young Adult
13.
Stress ; 16(5): 483-92, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23805796

ABSTRACT

The cortisol awakening response (CAR) is a much studied but poorly understood aspect of the circadian pattern of cortisol secretion. A Scopus search of "cortisol" and "awakening" reveals 666 publications in this area since 1997 when it was first identified by Pruessner and colleagues as a "reliable biomarker of adrenocortical activity". The primary focus of the majority of these studies is centered on its utility as a biomarker associated with a range of psychosocial, physical and mental health variables. Such studies typically examine differences in the CAR (studied on 1 or 2 days) between healthy participants and other comparator groups of interest. Fewer studies (25 in our estimation) have examined correlates of day-to-day variation in the CAR in healthy participants, informing its role and regulation within the healthy circadian pattern of cortisol secretion. This is the first review to examine these studies which, although limited in number, offer a relatively coherent emerging story about state factors that influence the CAR and the impact of the CAR on daily functioning. Greater understanding of these issues helps illuminate the utility of the CAR as a promising biomarker in psychophysiological and epidemiological research. The review also highlights areas that require greater clarification and points to potentially fruitful areas of further research.


Subject(s)
Circadian Rhythm/physiology , Hydrocortisone/metabolism , Wakefulness/physiology , Biomarkers/analysis , Female , Humans , Hypothalamo-Hypophyseal System/physiology , Light , Male , Pituitary-Adrenal System/physiology , Saliva/chemistry , Seasonal Affective Disorder/physiopathology , Sleep/physiology
14.
Psychoneuroendocrinology ; 38(9): 1476-83, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23312064

ABSTRACT

Linking psychosocial measures to the cortisol awakening response (CAR) demands accurate saliva sampling times. Monitoring adherence to the saliva sampling protocol requires electronic monitoring of both awakening and sampling times since self-reported times are inaccurate. Delays greater than 15 min between awakening and commencement of saliva sampling reduce CAR magnitude. Less delay has been judged tolerable but remains unexplored for different magnitude measures, and for timing of the CAR peak. Study 1: Fifty healthy females (21 ± 4 years) were instructed to collect saliva on four days at 0, 15, 30 and 45 min post-awakening (samples 1-4). Both self-reported awakening and sampling times were electronically monitored using actigraphy and track caps. Self-reported awakening was later than actigraph estimated awakening (median difference of 4 min). Estimates of CAR magnitude were significantly greater on non-adherent days (delay of 5-15 min) compared to adherent days (delay<5 min). On non-adherent compared to adherent days cortisol on average peaked earlier, at sample 3 rather than at sample 4. Study 2: Accurately timed cortisol values were obtained in an intensive investigation of 10 participants who collected saliva on 2 days every 5 min for 30 min post-awakening. Cortisol did not significantly increase until 10 min post-awakening, suggesting a time lag may be typical between awakening and observation of a cortisol increase. We conclude that moderate delays between awakening and collection of saliva samples previously considered tolerable result in erroneous estimation of CAR magnitude and timing of the peak. These results are attributed to an approximate 10 min time lag between awakening and the start of the cortisol rise. The absence of this latent period in calculations leads to overestimation of the CAR magnitude on moderately non-adherent sampling days. These findings, if more universally generalizable, will further theoretical understanding of the physiology of the CAR, but are methodologically challenging for researchers since self-reported awakening times are not accurate enough to override the concerns raised. However accurate electronic measurement of adherence to protocol would enable sampling delays to be taken into account in computing CAR estimates.


Subject(s)
Circadian Rhythm/physiology , Hydrocortisone/metabolism , Patient Compliance , Saliva/chemistry , Specimen Handling , Time Factors , Wakefulness/physiology , Actigraphy , Adult , Artifacts , Female , Humans , Male , Medical Records , Polysomnography/instrumentation , Polysomnography/methods , Secretory Rate , Self Report , Sex Factors , Specimen Handling/instrumentation , Specimen Handling/methods , Young Adult
15.
Stress ; 15(6): 601-7, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22356124

ABSTRACT

Although there is well-documented evidence for hyperactivity of hypothalamic-pituitary-adrenal (HPA) axis function in anorexia nervosa (AN), there has been little research into secretory patterns of salivary cortisol and dehydroepiandrosterone (DHEA) in this condition. The cortisol awakening response (CAR), a prominent and discrete feature of the cortisol cycle, has not been extensively explored in adolescent AN. Saliva samples were collected at awakening, 30 min and 12 h post-awakening on two consecutive weekdays from eight female adolescents with clinically diagnosed AN and 41 healthy control (HC) age-matched females. Adolescent AN patients had greater salivary cortisol and DHEA concentrations than HC girls at all points. Increased hormone secretion was unrelated to body mass index. However, despite hypersecretion of both hormones, the circadian pattern including the CAR paralleled that of the HC group. Findings from this preliminary study confirm dysregulation of HPA axis function in adolescent AN as evidenced by hypersecretion of both cortisol and DHEA, which share the common secretagogue adrenocorticotropic hormone. However, the parallel diurnal profiles for AN and HC participants, including the CAR, may indicate hypersecretion per se rather than differential regulation of the diurnal pattern of these two adrenal steroids in AN.


Subject(s)
Anorexia Nervosa/physiopathology , Circadian Rhythm/physiology , Dehydroepiandrosterone/metabolism , Hydrocortisone/metabolism , Saliva/metabolism , Adolescent , Female , Humans , Hypothalamo-Hypophyseal System/physiopathology , Pituitary-Adrenal System/physiopathology
16.
Anxiety Stress Coping ; 25(6): 711-8, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22091838

ABSTRACT

Retrieval-induced forgetting (RIF) refers to the finding that the retrieval of a memory trace suppresses the retrieval of rival memory traces, and there is evidence that RIF reflects the effects of cognitive inhibition. The Attentional Control Theory (ACT) postulates that cognitive inhibition will be impaired by a high level of state anxiety, but the effect of anxiety on RIF has not previously been investigated. A sample of 116 participants were tested on the RIF procedure, and were also administered the Spielberger State Anxiety Inventory and the Big Five Personality Inventory. The results indicated a significant negative correlation between RIF scores and state anxiety, and a significant positive correlation between RIF scores and extraversion. However, a multiple regression analysis identified extraversion as the main predictor of RIF performance. None of the other personality factors correlated with RIF scores. These findings are consistent with the predictions of the ACT.


Subject(s)
Anxiety/psychology , Mental Recall , Personality , Adolescent , Adult , Attention , Female , Humans , Male , Middle Aged , Models, Psychological , Personality Inventory , Psychological Tests , Young Adult
17.
J Child Psychol Psychiatry ; 52(2): 111-8, 2011 Feb.
Article in English | MEDLINE | ID: mdl-20695930

ABSTRACT

BACKGROUND: Attachment style has been linked with basal cortisol secretion in healthy adult women. We investigated whether dysregulation in basal cortisol secretion may be evident in younger healthy females. METHODS: Sixty healthy females aged 9-18 years (mean 14.16, SD ± 2.63 years) participated in the Attachment Style Interview (ASI). Eight saliva samples, synchronised to awakening, were collected per day on two consecutive weekdays to examine the cortisol awakening response (CAR) and the subsequent diurnal decline. RESULTS: Participants exhibiting an anxious attachment style had higher cortisol levels on awakening, in contrast to those who were securely attached. The anxious insecure group also showed an attenuated CAR compared to all other participants. Attachment style groups did not differ in cortisol secretion over the remainder of the day. CONCLUSIONS: These findings indicate that the same pattern of cortisol dysregulation associated with disorder in adulthood manifests as a function of anxious (but not avoidant) insecure attachment style in females during healthy childhood and adolescence.


Subject(s)
Anxiety/metabolism , Hydrocortisone/metabolism , Object Attachment , Saliva/metabolism , Adolescent , Child , Circadian Rhythm , Female , Humans , Time Factors
18.
Psychoneuroendocrinology ; 36(6): 816-23, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21145663

ABSTRACT

This study compared the daily pattern of free salivary cortisol secretion in winter and in summer between two groups; participants with self-assessed seasonal affective disorder (SAD) and age- and sex-matched healthy controls. Fifty-two participants completed the study with an equal number in each group. The diurnal pattern of cortisol secretion was assessed across two consecutive weekdays in summer, and two in winter, with conditions being counterbalanced. On each study day participants collected multiple saliva samples in the domestic setting to capture the cortisol awakening response (CAR) and declining levels across the day. In addition, perceived stress, anxiety, depression, state stress and state arousal were assessed using validated questionnaires. There was no evidence for any seasonal changes in psychological data or cortisol pattern for the healthy control population. In summer, self-assessed SAD and control participants had similar psychological and cortisol profiles. In winter however, SAD participants reported greater depression, stress and anxiety, and lower levels of arousal. Furthermore, the CAR was significantly attenuated in SAD participants during winter months. There was no difference in cortisol levels during the rest of the day between controls and SAD participants in winter. In line with the above findings and previous research, there was an inverse relationship between the increase in cortisol following awakening and a measure of seasonality in winter. Furthermore in winter, a general dysphoria construct correlated inversely with the CAR, indicating that participants reporting greater depression, stress and anxiety and lower arousal, exhibited lower CARs. In conclusion, during the shortened photoperiod in winter, the cortisol response to awakening is attenuated in participants with self-assessed SAD in comparison to controls. These findings contribute to the understanding of the physiology of SAD.


Subject(s)
Circadian Rhythm/physiology , Hydrocortisone/metabolism , Seasonal Affective Disorder/physiopathology , Seasons , Adult , Aged , Diagnostic Self Evaluation , Female , Humans , Hydrocortisone/analysis , Male , Middle Aged , Photoperiod , Saliva/chemistry , Suprachiasmatic Nucleus/physiopathology , Wakefulness
19.
Int Rev Neurobiol ; 93: 153-75, 2010.
Article in English | MEDLINE | ID: mdl-20970005

ABSTRACT

The cortisol awakening response (CAR) is a crucial point of reference within the healthy cortisol circadian rhythm, with cortisol secretion typically peaking between 30 and 45 min post awakening. This chapter reviews the history of investigation into the CAR and highlights evidence that its regulation is relatively distinct from cortisol secretion across the rest of the day. It is initiated by awakening, under the influence of the hypothalamic suprachiasmatic nucleus, and "fine tuned" by a direct neural input to the adrenal cortex by the sympathetic nervous system. This chapter also examples the CAR in relation to other awakening-induced processes, such as restoration of consciousness, attainment of full alertness, changes in other hormones, changes in the balance of the immune system, and mobilization of the motor system, and speculates that there is a role for the CAR in these processes.


Subject(s)
Hydrocortisone/metabolism , Hypothalamo-Hypophyseal System/metabolism , Pituitary-Adrenal System/metabolism , Wakefulness/physiology , Adrenal Cortex/blood supply , Adrenal Cortex/metabolism , Animals , Humans , Hydrocortisone/blood , Hypothalamo-Hypophyseal System/blood supply , Pituitary-Adrenal System/blood supply , Suprachiasmatic Nucleus/blood supply , Suprachiasmatic Nucleus/metabolism
20.
Neurosci Biobehav Rev ; 35(1): 97-103, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20026350

ABSTRACT

In most healthy people morning awakening is associated with a burst of cortisol secretion: the cortisol awakening response (CAR). It is argued that the CAR is subject to a range physiological regulatory influences that facilitate this rapid increase in cortisol secretion. Evidence is presented for reduced adrenal sensitivity to rising levels of ACTH in the pre-awakening period, mediated by an extra-pituitary pathway to the adrenal from the suprachiasmatic nucleus (SCN). A role for the hippocampus in this pre-awakening regulation of cortisol secretion is considered. Attainment of consciousness is associated with 'flip-flop' switching of regional brain activation, which, it is argued, initiates a combination of processes: (1) activation of the hypothalamic pituitary adrenal (HPA) axis; (2) release of pre-awakening reduced adrenal sensitivity to ACTH; (3) increased post-awakening adrenal sensitivity to ACTH in response to light, mediated by a SCN extra-pituitary pathway. An association between the CAR and the ending of sleep inertia is discussed.


Subject(s)
Hydrocortisone/physiology , Hypothalamo-Hypophyseal System/physiology , Pituitary-Adrenal System/physiology , Wakefulness/physiology , Animals , Humans , Sleep/physiology
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