Showing papers on "Morning published in 2008"
TL;DR: The hypothesis that sleep plays an active role in declarative memory consolidation even if delayed is supported and the results show for the first time the importance of sleep for declaratives memory consolidation during childhood.
149 citations
TL;DR: This work has implications for the study of physiological recovery from work, and also suggests a pathway by which marital satisfaction influences allostatic load and physical health.
Abstract: Design: Multilevel modeling was used to model relationships between salivary cortisol, daily diary ratings of work experiences, and Marital Adjustment Test scores (Locke & Wallace, 1959), in a sample of 60 adults who sampled saliva 4 times per day over 3 days. Results: Among women but not men, marital satisfaction was significantly associated with a stronger basal cortisol cycle, with higher morning values and a steeper decline across the day. For women but not men, marital satisfaction moderated the within-subjects association between afternoon and evening cortisol level, such that marital quality appeared to bolster women’s physiological recovery from work. For both men and women, evening cortisol was lower than usual on higher-workload days, and marital satisfaction augmented this association among women. Men showed higher evening cortisol after more distressing social experiences at work, an association that was strongest among men with higher marital satisfaction. Conclusion: This work has implications for the study of physiological recovery from work, and also suggests a pathway by which marital satisfaction influences allostatic load and physical health.
147 citations
TL;DR: A two-stage differential method is used to establish a daily traffic pattern that links the morning and evening commutes as an integrated one, and a location-dependent parking fee regime with no road tolls is proposed to optimize the morning commute pattern.
Abstract: For decades, the dynamic traffic patterns of morning and evening commutes have been investigated separately, and it is often assumed that they are simple mirror symmetries. In this paper, we use a two-stage differential method to establish a daily traffic pattern that links the morning and evening commutes as an integrated one. Based on a bi-direction bottleneck network with a spatial pattern of parking, we use analytical models to describe travelers’ behavior in choosing departure times in their morning and evening trips, where a commuter’s morning and evening decisions are joined by a parking location. Given fixed parking locations of commuters, we firstly derive the evening commute pattern, which is a Nash equilibrium in the sense that no one can reduce her/his travel cost given other commuters’ decisions. Then the individual evening commute costs are allocated to different parking locations in modeling the morning commuting behavior, and the morning travel pattern is a user equilibrium in the sense that everyone has equal daily travel cost and no one can reduce private travel cost by unilaterally changing travel decisions. Then we propose a time-varying road toll regime to eliminate queuing delay and reduce schedule delay penalty. Furthermore, a time-varying road toll and location-dependent parking fee regime is developed to achieve a system optimum where the morning schedule delay cost is further reduced to the minimum by reversing the spatial order of parking. In view of the fact that road pricing is hard to implement, we propose a location-dependent parking fee regime with no road tolls to optimize the morning commute pattern, without improving the evening commute pattern.
145 citations
TL;DR: A 4 h partial sleep deprivation at the end of the night appears to be more disturbing than partial sleep deprived at the beginning of thenight.
Abstract: The purpose of this study was to determine whether delaying bedtime or advancing rising time by 4 h affects anaerobic performance of individuals the following day in the morning and afternoon. Eleven subjects participated in the study, during which we measured the maximal, peak, and mean powers (i.e., P(max) [force-velocity test], P(peak), and P(mean) [Wingate test], respectively). Measurements were performed twice daily, at 07:00 and 18:00 h, following a reference normal sleep night (RN), a partial sleep deprivation timed at the beginning of the night (SDB), and a partial sleep deprivation timed at the end of the night (SDE), and oral temperature was measured every 4 h. Each of the three experimental conditions was separated by a one-week period. Our results showed a circadian rhythm in oral temperature, and analysis of variance revealed a significant sleep x test-time effect on peak power (P(peak)), mean power (P(mean)), and maximal power (P(max)). These variables improved significantly from the morning to the afternoon for all three experimental conditions. Whereas the morning-afternoon improvement in the measures was similar after the RN and SDB conditions, it was smaller following the SDE condition. There was no significant difference in the effect of the two sleep-deprivation conditions on anaerobic performances at 07:00 and at 18:00 h under the SDB condition in comparison with the post-reference night. However, the performance variables were significantly lower at 18:00 h after the SDE condition. In conclusion, a 4 h partial sleep deprivation at the end of the night appears to be more disturbing than partial sleep deprivation at the beginning of the night.
123 citations
TL;DR: Findings from this study suggest that younger men with a higher level of fatigue at the time of the simulation visit were at increased risk for higher levels of evening and morning fatigue over the course of RT.
107 citations
TL;DR: The results show the three‐dimensional model of mood is more advantageous in M‐types than in E‐types during the hours of typical human activity.
Abstract: The aim of the present study was to examine levels of energetic arousal (EA), tense arousal (TA), and hedonic tone (HT) in individuals with different circadian preferences. Subjects were males with extreme either morning (M-type) or evening (E-type) preferences (N=31), selected using the Morningness-Eveningness Questionnaire cutoff points derived from the Polish population norms. They completed the UWIST Mood Adjective Check List every 1.5 h between 08:00 to 20:00 h in laboratory conditions. The obtained data showed higher levels of TA and lower levels of HT in E-types over the whole day as compared to M-types. As for EA, M-types showed higher levels than E-types between 08:00 to 17:00 h, but the two groups showed no differences during the later hours of the day. Both groups were found to exhibit similar diurnal patterns in TA and HT, and dissimilarity between M-types and E-types appeared in the daily course of EA. The results show the three-dimensional model of mood is more advantageous in M-types than in E-types during the hours of typical human activity.
91 citations
TL;DR: It is concluded that the acutely hypotensive effects following 30 min of steady state exercise are less marked in the morning, probably because the exercise-mediated decrease in peripheral resistance is not as apparent at this time of day.
Abstract: The reactivity of ambulatory blood pressure following a given change in everyday physical activities is highest in the morning. Whether the acute response of blood pressure following a controlled bout of steady-state exercise is influenced by time of day is examined in this study. After 45 min of supine rest, 12 male normotensives completed 30 min of cycling at 70% $$ \dot V{\text{O}}_{{2{\text{peak}}}} $$
which began at either 0800 or 1600 hours. Arterial blood pressure, cardiac output, total peripheral resistance, cutaneous blood flow and temperature were determined before, and up to 90 min after, exercise. Mean ± SE arterial pressure, averaged over the acute (20-min) period, reduced by 7 ± 2 mmHg following exercise at 1600 hours but increased by 3 ± 3 mmHg following exercise at 0800 hours (P = 0.03). Total peripheral resistance fell by 4.2 ± 0.8 mmHg l−1 min−1 after exercise at 1600 hour, but increased slightly by 0.1 ± 0.5 mmHg l−1 min−1 after morning exercise (P = 0.02). We conclude that the acutely hypotensive effects following 30 min of steady state exercise are less marked in the morning, probably because the exercise-mediated decrease in peripheral resistance is not as apparent at this time of day.
88 citations
01 Jan 2008
TL;DR: The degree of frequency of microbial distribution was high in the bacteriological laboratory and female ward and lowest in the operating room (Theater) of the two major hospitals studied.
Abstract: The level of airborne microbial load of hospitals indoor is unknown in Benin City, Nigeria. A study of the quality and quantity of airborne microflora in two major hospitals, the Faith Medical Center and Central Hospital in Benin City was carried out to establish standard for future reference. Samples were collected using the settled plate techniques for the enumeration of bacterial and fungal isolates. Each day, the air samples were collected three times: in the morning between 10 and 11 am, in the afternoon between 12 noon and 2 pm and in the evening between 5 and 6 pm. The total heterotrophic microbial population of the five different wards studied from the two hospitals varied from wards to wards. The highest bacterial population was recorded in the evening between time 5 pm and 6 pm compared to the morning and afternoon, ranging from 15 cfu m to 47 3 cfu m in the Faith Medical Hospital and 17 cfu m to 52 cfu m in the Central Hospital, with the children 3 33 ward recording the highest bacterial counts of 47 cfu m and 52 cfu m in the Faith Medical Center and 33 Central Hospital respectively. The concentration of fungal population in air of the five different wards in the two hospitals studied was recorded high in the evening, with values ranging from 10 cfu m to 53 cfu m . 33 At the three different times of study, the male, female, children wards and bacteriological laboratory were observed to record high fungal population in the Faith Medical Center and the Central Hospital. The microbial isolates characterized and identified include six bacterial and four fungal genera, among which are the bacterial isolates: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis and Klebsiella aerogenes and the fungal isolates include Aspergillus, Penicillum, Mucor and Fusarium. The degree of frequency of microbial distribution was high in the bacteriological laboratory and female ward and lowest in the operating room (Theater).
87 citations
TL;DR: It is concluded that partial circadian realignment to night work in combination with reduced homeostatic pressure contributed to the greater efficacy of a schedule of Evening Sleep with a phase-advancing light exposure as a countermeasure against attentional impairment, over adule of Morning Sleep withA phase-delaying light exposure.
Abstract: The prevalence of hazardous incidents induced by attentional impairment during night work and ensuing commute times is attributable to circadian misalignment and increased sleep pressure. In a 10-day shift work simulation protocol (4 day shifts and 3 night shifts), the efficacies of 2 countermeasures against nighttime (2300 to 0700 h) attentional impairment were compared: (1) Morning Sleep (0800 to 1600 h; n = 18) in conjunction with a phase-delaying light exposure (2300 to 0300 h), and (2) Evening Sleep (1400 to 2200 h; n = 17) in conjunction with a phase-advancing light exposure (0300 to 0700 h). Analysis of the dim light salivary melatonin onset indicated a modest but significant circadian realignment in both sleep groups (evening sleep: 2.27 +/- 0.6 h phase advance, p 0.05). However, on the final night shift, the evening sleep subjects had 37% fewer episodes of attentional impairment (long response times: 22 +/- 4 vs. 35 +/- 4; p = 0.02) and quicker responses (p < 0.01) on the Psychomotor Vigilance Task than their morning sleep counterparts. Their response speed recovered to near daytime levels (p = 0.47), whereas those of the morning sleep subjects continued to be slower than their daytime levels (p = 0.008). It is concluded that partial circadian realignment to night work in combination with reduced homeostatic pressure contributed to the greater efficacy of a schedule of Evening Sleep with a phase-advancing light exposure as a countermeasure against attentional impairment, over a schedule of Morning Sleep with a phase-delaying light exposure. These results have important implications for managing patients with shift work disorder.
87 citations
TL;DR: The increased efficacy on ambulatory BP as well as the significantly reduced prevalence of edema after bedtime as compared to morning ingestion of nifedipine should be taken into account when prescribing this medication to patients with essential hypertension.
85 citations
TL;DR: The results support the idea that social schedules have an impact on the expression of circadian rhythmicity but this impact depends on the individual chronotype.
Abstract: Inter-individual differences in the phase of the endogenous circadian rhythms have been established. Individuals with early circadian phase are called morning types; those with late circadian phase are evening types. The Horne and Ostberg Morningness-Eveningness Questionnaire (MEQ) is the most frequently used to assess individual chronotype. The distribution of MEQ scores is likely to be biased by several fact, ors, such as gender, age, genetic background, latitude, and social habits. The objective of the present study was to determine the effect of different social synchronizers on the sleep/wake cycle of persons with different chronotypes. Volunteers were selected from a total of 1232 UFPR undergraduate students who completed the MEQ. Thirty-two subjects completed the study, including 8 morning types, 8 evening types and 16 intermediate types. Sleep schedules were recorded by actigraphy for 1 week on two occasions: during the school term and during vacation. Sleep onset and offset times, sleep duration, and mid-sleep time for each chronotype group were compared by the Mann-Whitney U-test separately for school term and vacation. School term and vacation data were compared by the Wilcoxon matched-pair test. Morning types showed earlier sleep times and longer sleep duration compared with evening types (23:00 ± 44 and 508.9 ± 50.27 vs 01:08 ± 61.95 and 456.44 ± 59.08, for the weekdays during vacation). During vacation, the subjects showed later sleep times, except for the morning types, who did not exhibit differences for sleep onset times. The results support the idea that social schedules have an impact on the expression of circadian rhythmicity but this impact depends on the individual chronotype.
TL;DR: This data indicates that pre‐existing long‐term glucocorticoid replacement therapy is suboptimal as the normal nocturnal rise and waking morning peak of serum cortisol is not reproduced.
Abstract: Summary
Background All existing long-term glucocorticoid replacement therapy is suboptimal as the normal nocturnal rise and waking morning peak of serum cortisol is not reproduced.
Aim To test whether it is possible to reproduce the normal overnight rise and morning peak in serum cortisol using an oral delayed and sustained release preparation of hydrocortisone (Cortisolds).
Subjects and methods Six healthy normal male volunteers attended on two occasions, in a single-dose, open-label, nonrandomized study. Endogenous cortisol secretion was suppressed by administration of dexamethasone. Cortisolds (formulation A or B) was administered at 2200 h on day 1. Blood samples for measurement of cortisol were taken from 2200 h every 30 min until 0700 h, then hourly until 2200 h on day 2. Fifteen body mass index (BMI)-matched control subjects had serum cortisol levels measured at 20-min intervals for 24 h. Serum cortisol profiles and pharmacokinetics after Cortisolds were compared with those in controls.
Results Formulations A and B were associated with delayed drug release (by 2 h and 4 h, respectively), with median peak cortisol concentrations at 4·5 h (0245 h) and 10 h (0800 h), respectively, thereby reproducing the normal early morning rise in serum cortisol. Total cortisol exposure was not different from controls.
Conclusions For the first time we have shown that it is possible to mimic the normal circadian rhythm of circulating cortisol with an oral modified-release formulation of hydrocortisone, providing the basis for development of physiological circadian replacement therapy in patients with adrenal insufficiency.
TL;DR: Midnight salivary cortisol is a simple, robust marker of remission after TSS for CD and is now recognized as a reliable index for Cushing's syndrome diagnosis but has to be validated for the follow-up of treated patients.
Abstract: Context: Midnight salivary cortisol (MSC) is now recognized as a reliable index for Cushing’s syndrome diagnosis but has to be validated for the follow-up of treated patients. Objective: Our objective was to evaluate MSC for assessing the outcome of transsphenoidal surgery (TSS) in patients with Cushing’s disease (CD). Design: We conducted a retrospective cohort study in a single center. Patients and Methods: Sixty-eight patients treated by TSS between 1996 and 2006 and followed for at least 6 months with postoperative MSC were included. Mean follow-up (± sd) was 45 ± 31 months. Morning plasma cortisol was determined 5 d after TSS, and MSC and urinary cortisol (UC) were determined 6–12 months after surgery. The remission group included hypocortisolic (morning plasma cortisol < 50 ng/ml and/or insufficient response to cosyntropin) and eucortisolic (midnight plasma cortisol < 75 ng/ml and normal UC) patients. Patients in the treatment failure group had high midnight plasma cortisol and UC concentrations. Re...
TL;DR: Adding a bedtime dose of an α-adrenergic blocker titrated by self-measured morning blood pressure in treated hypertensive patients with uncontrolled morning hypertension significantly reduced blood pressure and urinary albumin excretion rate, particularly in those with microalbuminuria.
Abstract: BackgroundThe impact on microalbuminuria of strict treatment aimed at lowering of self-measured morning blood pressure using an adrenergic blockade is unclear.MethodsWe conducted an open-label multicenter trial, the Japan Morning Surge-1 Study, that enrolled 611 hypertensive patients, whose self-mea
TL;DR: Although chronic isostrain did not affect the morning saliva cortisol measures, evening cortisol secretion was significantly elevated in the chronic high isstrain group throughout the whole week, concordant with the findings in other studies on long-term strain.
Abstract: The objective of this study was to assess long-term job strain impact on morning and evening salivary cortisol secretion. In all 77 white-collar workers (31% women; sample mean age, 42 years at baseline) volunteered to sample morning (immediately after waking up) and evening (10 p.m.) salivary cortisol for 7 consecutive days. By median split on aggregated self-reported isostrain from three consecutive questionnaires distributed in a period of approximately 3.5 years the participants were classified into a high or low long-term isostrain condition. Regardless of strain condition, there was a significant reduction in morning salivary cortisol secretion from the working week to the weekend, whereas evening salivary cortisol secretion showed no significant variation during the week. Although chronic isostrain did not affect the morning saliva cortisol measures, evening cortisol secretion was significantly elevated in the chronic high isostrain group throughout the whole week. The elevated evening cortisol measures associated with chronic high strain are concordant with the findings in other studies on long-term strain.
TL;DR: With recent advances in ambulatory BP monitoring and BP self-measurement and the inclusion of antihypertensive agents that target the underlying pathophysiological mechanisms related to the morning BP surge, control of morning hypertension is clinically feasible and should be an important therapeutic target.
Abstract: The early morning surge in blood pressure (BP) in patients with hypertension is associated with an increased risk of cardiovascular events, such as myocardial infarction and stroke, especially in the presence of comorbidities of diabetes, cardiac and renal disease. A variety of nonhemodynamic factors contribute to the early morning prothrombotic state, including increased atherothrombotic plaque vulnerability and endovascular shear stress, increased coagulability, platelet aggregation, and blood viscosity, and reduced fibrinolysis. In addition, there is a strong association between morning hypertension and vascular damage throughout the circulation, which may involve the myocardium, large arteries, and other target organs. Because morning hypertension is often unrecognized, the resultant target-organ damage may progress relentlessly. With recent advances in ambulatory BP monitoring and BP self-measurement and the inclusion of antihypertensive agents that target the underlying pathophysiological mechanisms related to the morning BP surge (ie, the sympathetic nervous system and the renin-angiotensin-aldosterone system), control of morning hypertension is clinically feasible and should be an important therapeutic target.
TL;DR: The results indicate that increased consumption of vegetables raises circulatory melatonin concentrations, which is contained in certain vegetables, which may have an influence on circulatorymelatonin concentrations.
Abstract: Melatonin, which is contained in certain vegetables, may have an influence on circulatory melatonin concentrations. This study examined the effects of the consumption of vegetables on 6-sulfatoxymelatonin concentrations in morning urine. Ninety-four healthy women aged 24-55 were recruited through a city public health center in Japan. The women randomly allocated to the intervention group were requested to consume high amounts of six selected vegetables, with a target of 350 g/day for 65 days, while those in the control group were asked to avoid the same six vegetables during the same period. First-void morning urine was collected before and at the end of the intervention period, and creatinine-adjusted 6-sulfatoxymelatonin concentrations were measured. At the end of the intervention period, daily mean intake of melatonin from the six vegetables was 1288.0 ng in the intervention group and 5.3 ng in the control group. In the intervention group, the mean concentration of 6-sulfatoxymelatonin changed from 48.1 [95% confidence interval (CI): 40.4-57.2] ng/mg creatinine to 49.6 (95% CI: 42.8-57.3) ng/mg creatinine across the intervention period. In the control group, the mean concentration of 6-sulfatoxymelatonin changed from 55.5 (95% CI: 48.7-63.2) ng/mg creatinine to 50.8 (95% CI: 44.0-58.7) ng/mg creatinine across the intervention period. A comparison of the two groups with regard to the changes in the 6-sulfatoxymelatonin concentrations across the intervention period showed a significant difference (P = 0.03). The results indicate that increased consumption of vegetables raises circulatory melatonin concentrations.
TL;DR: The morning surge of blood pressure is poorly reproducible, irrespective of whether it is analysed as continuous or categorical variable.
Abstract: Objective Using 24-h ambulatory blood pressure monitoring, we studied the repeatability of the morning blood pressure in older (>= 60 years) patients with isolated systolic hypertension.
Methods The sleep-through morning surge was the morning blood pressure minus the lowest nighttime blood pressure. The preawake morning surge was the morning blood pressure minus the preawake blood pressure. In addition, we determined the cusum plot height of blood pressure from 04: 00 to 10: 00 h from a plot of cumulative sums.
Results In 173 patients with repeat recordings within 33 days (median), the short-term repeatability coefficients, expressed as percentages of maximal variation, ranged from 35 to 41% for the daytime and nighttime blood pressures and from 50 to 56% for the night-to-day blood pressure ratios. Short-term repeatability ranged from 52 to 75% for the sleep-through and the preawake morning surge, and from 51 to 62% for the cusum plot height. In 219 patients with repeat recordings within 10 months (median), the corresponding long-term estimates ranged from 45 to 64%, from 69 to 71%, from 76 to 83%, and from 50 to 78%, respectively. In categorical analyses of the short-term repeatability of the sleep-through morning surge and the preawake morning surge, using the 75th percentile as arbitrary cut-off, surging status changed in 28.0 and 26.8% of patients (k-statistic <= 0.33). In the long-term interval, these proportions were 32.0 and 32.0%, respectively (k-statistic <= 0.20). The k-statistic threshold for moderate reproducibility is 0.4.
Conclusion The morning surge of blood pressure is poorly reproducible, irrespective of whether it is analysed as continuous or categorical variable.
TL;DR: Results indicate that it would be worthwhile testing the effect of morning versus afternoon vaccine administration on immune response in a large randomized control trial with vaccination during time periods representing the extremes of hormonal and cytokine diurnal rhythms.
Abstract: Variation in response to vaccination, particularly in vulnerable groups, provides a strong rationale for developing vaccine adjuvants. If there were consistent diurnal variation in immune response, this could inform a simple intervention for enhancing vaccine efficacy. Data from two studies are presented examining morning versus afternoon vaccine administration; in the first, hepatitis A vaccine was administered to young adults, and in the second, influenza vaccine to older community-based adults. Men, but not women, vaccinated in the morning mounted a better peak antibody response to both hepatitis A and the A/Panama influenza strain. These results indicate that it would be worthwhile testing this effect in a large randomized control trial with vaccination during time periods representing the extremes of hormonal and cytokine diurnal rhythms.
TL;DR: It is suggested that basic performance timing in young athletes is determined to some extent by naturally occurring M-E predispositions, and modification of time-of-day influences may be possible by routine practice at the same time each day, as was suggested here by the absence of evening superiority in performances.
Abstract: During adolescence and early adulthood, most humans are predisposed developmentally, both biologically and socially, toward evening/night activity. The morningness-eveningness (M-E) tendency to be an evening-preferring (E-type) rather than a morning-preferring (M-type) or intermediate/neither (N-type) "chronotype" may affect athletic performance at various times of day. This study evaluated M-E effects on rowing performance of an intact, experienced, university club crew with near-daily early morning (0500-0700 hours) and late afternoon (1630-1800 hours) training schedules. The hypothesis tested was that chronotype would modify circadian effects during morning and afternoon performances. Eight men and eight women (mean age 19.6 +/- 1.5 years) were tested in a randomized, counterbalanced design. A standard qualifying 2000-m ergometer rowing sprint and a nonroutine standing broad jump task were measured during early morning and late afternoon, separated by 3 days of rest. Each subject's chronotype was determined using two standard self-rating M-E scales, resulting in eight E-type (three women/five men), four M-type (two women/two men), and four N-type (three women/one man) subjects. The rowing results show that E-type and N-type subjects did not differ between morning and afternoon rowing performances, whereas M-type subjects rowed significantly faster in the morning. In contrast, the standing broad jump showed no consistent time-of-day or chronotype effect. These findings suggest that basic performance timing in young athletes is determined to some extent by naturally occurring M-E predispositions. Further, modification of time-of-day influences may be possible by routine practice at the same time each day, as was suggested here by the absence of evening superiority in performances. Understanding their personal M-E tendencies could allow young athletes to arrange training schedules at specific times of day to help counteract any natural circadian influences that might work against their performance.
TL;DR: This article conducted 262 call-broadcast point-count surveys using standardized North American Marsh Bird Monitoring Protocols between 31 May and 7 July 2006 on St. Vincent National Wildlife Refuge, an island off the northwest coast of Florida.
Abstract: We conducted 262 call-broadcast point-count surveys (1–6 replicate surveys on each of 62 points) using standardized North American Marsh Bird Monitoring Protocols between 31 May and 7 July 2006 on St. Vincent National Wildlife Refuge, an island off the northwest coast of Florida. We conducted double-blind multiple-observer surveys, paired morning and evening surveys, and paired morning and night surveys to examine the influence of call-broadcast and time of day on detection probability. Observer detection probability for all species pooled was 75% and was similar between passive (69%) and call-broadcast (65%) periods. Detection probability was higher on morning than evening (t = 3.0, P = 0.030) or night (t = 3.4, P = 0.042) surveys when we pooled all species. Detection probability was higher (but not significant for all species) on morning compared to evening or night surveys for all five focal species detected on surveys: Least Bittern (Ixobrychus exilis), Clapper Rail (Rallus longirostris), Pur...
TL;DR: It is concluded that mean arterial BP shows highest reactivity to a controlled bout of exercise when performed in the morning, and cannot be attributed simply to the residual effects of sleep, as it was not observed when participants exercised after a period of daytime sleep.
Abstract: Recently, we found that the reactivity of ambulatory blood pressure (BP) to everyday physical activities is highest in the morning. All participants in that study slept normally at night and freely chose their activity levels, which did not allow a separation of any circadian influence on the BP response from the effects of sleep per se. Therefore, the aims of the present study were to investigate whether there is circadian variation in the BP response to a controlled bout of exercise, and whether or not such variation is explained by the residual masking effects of nocturnal sleep. Following 4 h of nocturnal sleep, six normotensive males exercised on a cycle ergometer at 04:00, 06:00, 08:00, and 10:00 h. On a separate day, participants also slept for 4 h in the afternoon and then exercised at 16:00, 18:00, 20:00, and 22:00 h. Mean arterial BP, cardiac output (CO), heart rate (HR), and total peripheral resistance (TPR) were measured for 5 min before and 5, 10, 15, and 20 min after each exercise bout. Post...
TL;DR: Findings are compatible with the notion that transference effects represent everyday social-cognitive functioning related to activation of social schemata, but suggest that such effects might be particularly likely to occur when an individual's mental resources are limited, as might be the case during circadian mismatches.
Abstract: A study examined the relation between individuals' circadian rhythm and their tendency to exhibit transference effects in social perception. Individuals tested at times of circadian mismatch (i.e., morning persons tested in the evening and evening persons tested in the morning) exhibited more pronounced transference effects than individuals tested at times of circadian match (i.e., morning persons tested in the morning and evening persons tested in the evening). These findings are compatible with the notion that transference effects represent everyday social-cognitive functioning related to activation of social schemata. Additionally, however, they suggest that transference effects are not the inevitable consequence of activating the significant other's schema. Rather, such effects might be particularly likely to occur when an individual's mental resources are limited, as might be the case during circadian mismatches. This latter suggestion differs from psychodynamic views of transference as exclusively a driven, energy-intensive phenomenon.
TL;DR: This study is the first to explore psychosocial influences on hypothalamic-pituitary-adrenal axis activity in 4-year-old children transitioning to primary school over a 12-month period and supports social isolation over time as a key element in developmental endocrine activation.
Abstract: This study examined psychosocial influences on hypothalamic-pituitary-adrenal axis activity in 105 4-year-old children transitioning to primary school. Measuring before, during, and after school transition over a period of up to 12 months, salivary cortisol was assessed on awakening and early evening. Parents reported child temperament and teachers recorded adaptive behavior. Whilst cortisol at awakening and early evening increased from baseline to school transition, effects were not significant. A significant decrease occurred between transition and follow-up and from baseline to follow-up for both awakening and evening cortisol. Poorer effortful control was associated with high morning and steeper diurnal slope of cortisol at transition whilst surgency/extroversion was associated individually with greater morning and evening cortisol at transition and adaptation. Greater increase in internalizing social isolation during the first 6 months of school in more surgent/extrovert children predicted higher morning and evening cortisol at follow-up. This study is the first to explore these adaptive relationships over a 12-month period and supports social isolation over time as a key element in developmental endocrine activation.
TL;DR: The results demonstrate the strong link between ingestion and digestion patterns, and its impact on nutrient supply at the same amount of resource allocation, nutrient supply to grazing cattle can be modified through strategic grazing management.
Abstract: This work aimed to assess the impact of timing of herbage allocation and fasting on patterns of ingestive behavior, herbage intake, ruminal fermentation, nutrient flow to the duodenum, and site and extent of digestion. Treatments were daily herbage allocation in the afternoon (1500 h, AHA), morning (0800 h, MHA), AHA after 20 h of fasting (AHAF), and MHA after 20 h of fasting (MHAF). Four ruminally and duodenally fistulated heifers (279 +/- 99 kg of BW) individually strip-grazed wheat pastures in a Latin-square design. Eating, rumination, and idling behavior were recorded every 2 min, and bite and eating step rates were measured hourly while the heifers were grazing (11 h MHA and AHA; 4 h MHAF and AHAF). Ruminal DM pools were measured 4 times daily (0800, 1200, 1500, and 1900 h) to estimate daily herbage DMI and its pattern. Ruminal fluid was sampled at these same times and also at 2300 h. Duodenal digesta was sampled over 2 d to determine the site of herbage digestibility. Treatments did not affect daily herbage DMI (16.5 g/ kg of BW, SE = 0.0025; P > 0.05). However, they altered the eating pattern; the evening grazing bout of AHA and AHAF was greater (P 0.05) among MHA, MHAF, and AHAF; however, it averaged 970, 40, 300, and 540 g/d, respectively, greater (P 0.05) for MHA, AHA, and AHAF, but was lower for MHAF (P 0.05) within fasted and nonfasted treatments; however, it was greater (P 0.05) among MHA, MHAF, and AHAF, but was greater (P < 0.05) for AHA. The results demonstrate the strong link between ingestion and digestion patterns, and its impact on nutrient supply. At the same amount of resource allocation, nutrient supply to grazing cattle can be modified through strategic grazing management.
TL;DR: This study managed many of the problems found in naturalistic research on cortisol and provides norms for morning cortisol levels in 15-year-old adolescents.
TL;DR: It is suggested that daily perceived stress in children may impoverish cognitive performance via its modulating effects on the HPA axis activity.
Abstract: The aim of the present study was to assess the effects of daily stress perception on cognitive performance and morning basal salivary cortisol and alpha-amylase levels in healthy children aged 9-12. Participants were classified by whether they had low daily perceived stress (LPS, n = 27) or a high daily perceived stress (HPS, n = 26) using the Children Daily Stress Inventory (CDSI). Salivary cortisol and alpha-amylase were measured at awakening and 30 minutes later. Cognitive performance was assessed using the Cognitive Drug Research assessment system. The HPS group exhibited significantly poorer scores on speed of memory (p < .05) and continuity of attention (p < .05) relative to the LPS group. The HPS group also showed significantly lower morning cortisol levels at awakening and at +30 minutes measures in comparison with the LPS group (p < .05), and mean morning cortisol levels were negatively correlated with speed of memory (p < .05) in the 53 participants. No significant differences were observed between both groups in alpha-amylase levels. These findings suggest that daily perceived stress in children may impoverish cognitive performance via its modulating effects on the HPA axis activity.
TL;DR: The findings show that self‐ratings of rest and recovery are related to cortisol, particularly to morning cortisol, and that self-ratings provide important information on physiological recovery in terms of cortisol output.
Abstract: To date, the understanding of how recovery from work relates to cortisol output is poor. Considering this, the present study set out to investigate the associations between self-ratings of 15 items of rest and recovery and salivary cortisol sampled every second hour across two working days. Data came from 12 female and 13 male white-collar workers and were analyzed by linear regression analyses and repeated measures ANOVA. Poor rest and recovery was associated with high levels of morning cortisol, with the strongest relationships emerging for "rested in the morning", "rested after a weekend", "feel energetic during the working day", "tired during the working day", "sufficient sleep" and "worry about something". Moreover, significant interaction effects emerged between sex and "rested after a weekend" and "worry about something". To conclude, the findings show that self-ratings of rest and recovery are related to cortisol, particularly to morning cortisol, and that self-ratings provide important information on physiological recovery in terms of cortisol output.
TL;DR: The stronger mother-infant than father-Infant cortisol level correlations probably mirror that mother and infant not only have genetic similarities but also have been exposed to similar environmental conditions to a higher degree than father and infant.
TL;DR: Data suggested that sleep loss at different times of the night affects the hypothalamic-pituitary-adrenal axis (HPA-axis) differentially, even though SWS time and anxiety levels changed roughly in the same manner in both conditions.