Mark P. Roy

Life events and social support as moderators of individual differences in cardiovascular and cortisol reactivity.

Whether prior stress increases acute stress reactivity is unresolved. The impact of life events (within the past 12 months) and social support on cardiovascular responses was investigated in 90 young male firefighters. Cardiovascular and cortisol measures were collected across baseline, arithmetic, and speech tasks; intertask recovery; and three recovery trials. Reactivity differences were not independently associated with life events. High social support was associated with greater arithmetic cardiovascular reactivity and faster recovery. Combined life events and social support grouping showed that effects of support were accentuated when event frequency was high, suggesting that life events and support interacted to sensitize future stressor responses. Support may promote the alerting response mobilization but prevent chronic allostatic load by enhancing recovery.

Psychological, cardiovascular, and metabolic correlates of individual differences in cortisol stress recovery in young men

The relationship of free salivary cortisol stress recovery and basal cortisol with psychological, cardiovascular and metabolic factors was investigated in 82 healthy young men. Blood pressure, heart rate, cortisol and mood were assessed during a single laboratory session involving mental arithmetic and speech tasks, and lipid profiles were analysed from a fasting blood sample. Participants were divided into high (n=31) and low (n=51) cortisol stress recovery groups on the basis of the magnitude of changes between the peak cortisol responses to tasks and the lowest levels recorded at the end of a 30 min post-stress rest period. The high recovery group showed consistent increases in cortisol following each of the tasks, while the low recovery group showed little change across the session. Cortisol levels in the two groups did not differ at the end of the post-stress recovery period. The groups were indistinguishable in age, body mass index, smoking and alcohol consumption, and did not differ in psychological characteristics including anxiety, depression and perceived social support. However, the high stress recovery group had elevated low density lipoprotein cholesterol and total cholesterol/high density lipoprotein ratios, suggesting raised cardiovascular disease risk. The high stress recovery group also reported greater psychological activation during tasks, and greater recent minor life stress, than did the low recovery group. There was no association between rate of cortisol recovery and cardiovascular responses to tasks. But resting cortisol was related to blood pressure stress reactivity, suggesting that cortisol played a permissive role in augmenting sympathetically-driven cardiovascular responses. The results suggest that the rate of cortisol stress recovery is associated with variations in metabolic risk, and with differences in psychological state but not trait characteristics.

Cardiovascular stress reactivity and job strain as determinants of ambulatory blood pressure at work.

Objective To test the hypothesis that cardiovascular reactivity to laboratory mental stressors interacts with job strain in predicting blood pressure at work. Design Ambulatory monitoring of blood pressure and heart rate was carried out for an 8-h period on a work day and on an equivalent non-work day in 49 male firefighters. Methods Participants were recruited from a larger cohort (n = 90) on the basis of showing high or low systolic reactions to mental arithmetic 15–24 months previously, coupled with high or low ratings of perceived job strain (high demand-low control). Four groups were tested: low job strain-low systolic reactors (n = 12), low job strain-high systolic reactors (n = 12), high job strain-low systolic reactors (n = 12) and high job strain-high systolic reactors (n = 13). Results Systolic blood pressure (SBP) was higher on work than non-work days, and diastolic blood pressure and heart rate were higher at work in the morning but not in the afternoon. These effects were due partly to posture and physical activity differences between the two days. Neither job strain nor laboratory reactivity independently predicted ambulatory blood pressure. However, SBP was significantly higher during the afternoon at work in the high job strain-high systolic reactors than in the other groups. This was independent of baseline SBP, and was not due to differences in posture or activity at the time of recordings. Ambulatory SBP reactivity (difference between ambulatory values and workplace resting levels) in the afternoon at work was also elevated significantly in high job strain-high systolic reactors compared with in the other groups. Conclusions The results support the hypothesis that individual differences in the appraisal of work stress modulate the relationship between stress reactivity and ambulatory blood pressure.

Patterns of cortisol reactivity to laboratory stress

Cortisol responses to a laboratory stress protocol were investigated in 82 male firefighters. Saliva samples were collected during an adaptation period beginning between 9 and 10 am, and then at the end of each of six 10-min trials (a mental arithmetic task, an inter-task recovery period, a speech task, and three recovery periods). Individual differences in the mean cortisol response to the stress tasks were characterized by variation in the direction of the response, as well as the size of the response. Neither pre-stress cortisol levels nor responses were correlated with cardiovascular and mood responses. Cortisol levels before stress task presentation were negatively correlated with recent stress severity. Larger mean cortisol responses were associated with lower reports of recent stress exposure, lower negative affect scores, and a coping style characterized less experience of anger, more control over anger expression, and a tendency to screen out threatening information in stressful situations. Thus, increased cortisol activity was associated with less recent stress exposure and a more adaptive behavioral style than for those whose cortisol levels fell or were largely unchanged in response to a laboratory stressor.

Daily stressors and social support availability as predictors of depressed mood in male firefighters

Abstract The influence of daily stressors and social support availability on depressed mood was assessed over a 9-month period in 68 male firefighters. At 3-monthly intervals, an abbreviated Daily Stress Index (DSI) was completed for 16 days prior to administration of the Beck Depression Inventory (BDI). After negative affectivity, depressed mood and daily stress levels 3 months previously had been taken into account statistically, the DSI predicted subsequent BDI scores at the 3-, 6- and 9-month assessments. At the 3-and 6-month assessments, social support buffered the impact of DSI on depressed mood. By contrast, daily stress scores were not predicted by prior depressed mood or social support. The results are interpreted to support the causal influence of daily stressors on depressed mood, and the protective effect of social support.

Intraindividual variation in recent stress exposure as a moderator of cortisol and testosterone levels.

Intraindividual variation in recent stress exposure and its impact upon cortisol and testosterone was investigated. Over 1 year, 72 young male firefighters completed the Daily Stress Inventories, for 2 shift cycles (16 days), every 3 months. At the end of each 16-day period each participant attended a 1-hr morning assessment session. Saliva samples and blood pressure measurements were taken at 10-min intervals, and at 30 min, a blood sample was drawn. Across the year of assessment, there were significant linear relationships in reported stress and in neuroendocrine activity. In contrast to expectations, as daily stress decreased across the year (p < .008), salivary cortisol increased (p < .001) and testosterone levels decreased (p < .001). Within-subjects comparisons of the sessions with the highest and lowest stress confirmed these linear relationships: Lower stress prior to the assessment session was associated with higher cortisol levels (p < .01). These results, though in contrast to the orthodoxy concerning the association between stress and cortisol, are supported by findings in a number of other studies and may constitute down regulation of cortisol activity following an increment in stress exposure.

Testicular Self-Examination in an Adult Community Sample

The study investigated the impact of relationship status on participants’ knowledge of testicular cancer and their current and planned testicular self-examination (TSE) behavior. Adult male civil servants (N = 188) were recruited in the northwest of the United Kingdom (mean age = 33.37 years, SD = 10.77). The survey instrument asked about current and intended TSE practice, knowledge of testicular cancer, as well as attitudes and beliefs toward testicular cancer and self-examination. Factor analysis identified five factors equating to the benefits of TSE, fear, perceived risk, knowledge, and fatality. In logistic regression models, the benefits of TSE, fear, and knowledge significantly predict current TSE behaviors, whereas the benefits of TSE and perceived risk predicted future TSE intentions. Models predicting TSE practice differed according to relationship status. The findings suggest that strategies designed to promote TSE should be sensitive to individual differences in the influences on a person’s motivation to engage in TSE.

Pins & Needles: Towards Limb Disownership in Augmented Reality

The seemingly stable construct of our bodily self depends on the continued, successful integration of multisensory feedback about our body, rather than its purely physical composition. Accordingly, pathological disruption of such neural processing is linked to striking alterations of the bodily self, ranging from limb misidentification to disownership, and even the desire to amputate a healthy limb. While previous embodiment research has relied on experimental setups using supernumerary limbs in variants of the Rubber Hand Illusion, we here used Augmented Reality to directly manipulate the feeling of ownership for one’s own, biological limb. Using a Head-Mounted Display, participants received visual feedback about their own arm, from an embodied first-person perspective. In a series of three studies, in independent cohorts, we altered embodiment by providing visuotactile feedback that could be synchronous (control condition) or asynchronous (400ms delay, Real Hand Illusion). During the illusion, participants reported a significant decrease in ownership of their own limb, along with a lowered sense of agency. Supporting the right-parietal body network, we found an increased illusion strength for the left upper limb as well as a modulation of the feeling of ownership during anodal transcranial direct current stimulation. Extending previous research, these findings demonstrate that a controlled, visuotactile conflict about one’s own limb can be used to directly and systematically modulate ownership – without a proxy. This not only corroborates the malleability of body representation but questions its permanence. These findings warrant further exploration of combined VR and neuromodulation therapies for disorders of the bodily self.