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This study aimed to examine the relationship between trait resilience and salivary cortisol in a group of Chinese undergraduates. The Chinese versions of the Brief Resilience Scale and a measure of optimism, the revised Life Orientation Test were administered to 49 Chinese undergraduates who provided self-collected saliva samples six times per day (immediately after waking; 0.5, 3, 6, and 12 h thereafter; and at bedtime) over 3 consecutive weekdays. The cortisol data were aggregated across the 3 days to examine the association between resilience and components of the diurnal rhythm of cortisol using multiple regression. The results showed that higher resilience was associated with a stronger cortisol response to awakening and a steeper diurnal decline in cortisol from waking to bedtime. Resilience was positively associated with cortisol output over the course of the day but this relationship was not significant (p = 0.065). This pattern of diurnal rhythm is consistent with that typically observed in better adjusted individuals. Generated by an intensive protocol with compliance objectively monitored, these findings clearly indicate the important role of the hypothalamic-pituitary-adrenocortical axis in health and adjustment and contribute to the growing literature on resilience and cortisol in humans.

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This study used an intensive protocol to examine the effects of daily hassles and loneliness on diurnal salivary cortisol levels. Fifty Chinese undergraduates (28 females) provided six saliva samples each day for two consecutive days (at 0, 0.5, 3, 6, and 12 h after waking and at bedtime) and completed a questionnaire that included scales to measure daily hassles experienced over the previous month, trait loneliness, and depression. Cortisol data were aggregated over two days and used in subsequent analyses, focusing on the cortisol awakening response, diurnal slope, and overall cortisol output operationalized as the area under the curve with reference to the ground (AUCG). Multiple regression analysis showed that an increase in loneliness had a significant association with an increase in the AUCG and with a steeper diurnal slope. Loneliness also showed a significant interaction with daily hassles in that the positive association between daily hassles and AUCG was accentuated in the participants who reported a greater degree of loneliness. Our findings demonstrate for the first time the importance of trait loneliness in modulating the association between daily hassles and diurnal cortisol levels, which has significant clinical implications. Interventions to reduce loneliness should help college students to better cope with daily stressors. Increased attention should also be paid to the health implications of an elevated cortisol level in this relatively young and healthy population.

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A stronger motivation to cultivate social ties in older adults (ages range from 62 to 86 years) has been associated with a cortisol profile similar to that observed in undergraduate students, who are decades younger. We have shown the cultivation of social networks buffers against increases in diurnal cortisol common in old age. Cortisol is crucial for the response to stress and the process of ageing, and a recent study has demonstrated that a lower cortisol level is associated with longevity. We link the findings of social network cultivation and cortisol profile to the processes of biological ageing through DNA telomere length. Telomeres are repeated DNA sequences that cap and protect the ends of chromosomes, and telomere length is considered a potential biomarker for biological age because it is closely related to the cellular process of ageing and chronic stress and is inversely related to chronological age. Studies examining biological ageing have shown an association between an altered cortisol profile and telomere length dynamics. Together, these findings on social networks, cortisol profiles and telomere length suggest that seniors who are motivated to maintain social ties are biologically younger. We therefore propose the 'rejuvenation hypothesis', which posits that seniors with a stronger motivation for social network cultivation are biologically younger, as measured by cortisol levels and telomere length, than their peers who are less motivated to pursue social relationships. This idea suggests a new perspective and potentially fruitful direction for geriatric research. The focus on social network cultivation adds an important psychosocial dimension to rejuvenation therapies that so far have been dominated by biomedical approaches. The rejuvenation hypothesis also has important implications for social policy by supporting the viability of promoting network cultivation among the elderly to facilitate healthy ageing.

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BACKGROUND: Caregivers of relatives with Alzheimer's disease are highly stressed and at risk for physical and psychiatric conditions. Interventions are usually focused on providing caregivers with knowledge of dementia, skills, and/or support, to help them cope with the stress. This model, though true to a certain extent, ignores how caregiver stress is construed in the first place. Besides burden, caregivers also report rewards, uplifts, and gains, such as a sense of purpose and personal growth. Finding benefits through positive reappraisal may offset the effect of caregiving on caregiver outcomes. DESIGN: Two randomized controlled trials are planned. They are essentially the same except that Trial 1 is a cluster trial (that is, randomization based on groups of participants) whereas in Trial 2, randomization is based on individuals. Participants are randomized into three groups - benefit finding, psychoeducation, and simplified psychoeducation. Participants in each group receive a total of approximately 12 hours of training either in group or individually at home. Booster sessions are provided at around 14 months after the initial treatment. The primary outcomes are caregiver stress (subjective burden, role overload, and cortisol), perceived benefits, subjective health, psychological well-being, and depression. The secondary outcomes are caregiver coping, and behavioral problems and functional impairment of the care-recipient. Outcome measures are obtained at baseline, post-treatment (2 months), and 6, 12, 18 and 30 months. DISCUSSION: The emphasis on benefits, rather than losses and difficulties, provides a new dimension to the way interventions for caregivers can be conceptualized and delivered. By focusing on the positive, caregivers may be empowered to sustain caregiving efforts in the long term despite the day-to-day challenges. The two parallel trials will provide an assessment of whether the effectiveness of the intervention depends on the mode of delivery. TRIAL REGISTRATION: Chinese Clinical Trial Registry (http://www.chictr.org/en/) identifier number ChiCTR-TRC-10000881.

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Psychobiological research on aging in humans has been confounded by individual differences that have not been adequately characterized in the literature. This paper is an attempt to shed light on this issue by examining the impact of social network characteristics predictive of successful aging on salivary cortisol among 78 older Chinese people in Hong Kong. Eight salivary cortisol samples were collected each day for two consecutive days from immediately after awakening to 12 hours later. Two components of the cortisol diurnal cycle, response to awakening and diurnal decline, were examined in relation to social network characteristics including size, emotional support, and cultivation. ANOVAs with repeated measured were run to examine influences of the three social network characteristics on the cortisol awakening response and diurnal decline, with the effects of gender, age, socioeconomic status, and waking time controlled. Results indicated that those who spent more time and effort in developing and strengthening their social ties (i.e., those high in "cultivation") exhibited a significantly greater rise in cortisol in the morning and a significantly steeper decline over the day, thus attesting to more effective activation and deactivation of the HPA axis. Network cultivation reflected a positive motivation to nurture social relationships more than the other two network characteristics. Its effect on cortisol might stem from the positivity underlying the motivation.

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This study examined the impact of an important factor contributing to successful aging, humor, on post-awakening cortisol levels among a group of 45 older men whose ages ranged from 64 years to 86 years (mean=73.6 years). Four saliva samples were collected from the participants for 2 days immediately after waking and every 15 min thereafter for three times. Cortisol data of the 2 days were aggregated for analysis. Two separate indices of cortisol awakening response reflecting the mean level of secretion and the rise from immediately to 45 min post-awakening, AUC(G) and AUC(I), were computed using the trapezoid formula. The relation of these two indices to humor (operationalized as coping) was examined in a multiple regression analysis while controlling for the effect of age, socioeconomic status, and self-esteem. Results indicated that higher humor scores were associated with lower AUC(G) but had no relation with AUC(I). Findings of the present study suggest that the hypothalamic-pituitary-adrenocortical axis is the major pathway whereby positive psychological dispositions, such as humor, exert their health effects in the aging population. Moreover, cortisol levels in the awakening period may be particularly sensitive to the influences of psychosocial factors.

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OBJECTIVES: Research on stress and salivary cortisol has focused almost exclusively on the effects of negative psychological conditions or emotional states. Little attention has been drawn to the impact associated with positive psychological conditions, which have been shown recently to have significant influences on neuroendocrine regulation. The aim of this study is to examine the impact of optimism and positive affect on salivary cortisol with the effects of their negative counterparts controlled for. DESIGN: Optimism and pessimism, and positive and negative affectivity were studied in relation to the diurnal rhythm of salivary cortisol in a group of 80 Hong Kong Chinese, who provided six saliva samples over the course of a day on two consecutive days. The separate effects of optimism and positive affect on two dynamic components of cortisol secretion, awakening response, and diurnal decline were examined. METHODS: Optimism and pessimism were measured using the Chinese version of the revised Life Orientation Test while generalized affects and mood states were assessed by the Chinese Affect Scale. An enzyme-linked immunoabsorbent assay kit (EIA) developed for use in saliva was adopted for the biochemical analysis of cortisol. Testing of major group differences associated with positive psychological conditions was carried out using two-way (group by saliva collection time) ANOVAs for repeated measures with negative psychological conditions and mood states as covariates. RESULTS: Participants having higher optimism scores exhibited less cortisol secretion in the awakening period when the effect of pessimism and mood were controlled. This effect was more apparent in men than in women who had higher cortisol levels in the awakening period. Optimism did not have similar effect on cortisol levels during the underlying period of diurnal decline. On the other hand, higher generalized positive affect was associated with lower cortisol levels during the underlying period of diurnal decline after the effects of negative affect and mood states had been controlled. Generalized positive affect did not significantly influence cortisol secretion during the awakening period. CONCLUSIONS: These findings suggest that positive psychological resources including optimism and generalized positive affect had higher impact on cortisol secretion than their negative counterparts, and point to the need for increased attention to the potential contribution of positive mental states to well-being.

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