Indicators Of Stress In Humans Research Articles

Signal value of stress behaviour

Physiological and psychological stress are accompanied by nonverbal behaviour across a wide range of species. The function of this ‘stress behaviour’ is not well understood but is often assumed to be read by others as a cue to stress. Displaying signs of weakness is, however, difficult to understand from an evolutionary perspective and therefore further investigation into why these behaviours exist is needed. Here, we test whether displacement behaviours (i.e., those known to be associated with stress) are reliable indicators of stress in humans. To do this, we presented raters ( N = 133) with videos of individuals ( N = 31) undergoing a stress-inducting task. Self-directed displacement behaviours and self-reported stress were both associated with stress ratings given by raters. Therefore, such behaviours can provide reliable information to others and can be considered communicative. Individuals producing more nonverbal stress behaviour were rated as more likeable by raters (perhaps presenting as more honest signallers), indicating a benefit and potential adaptive function of displaying stress. Raters also differed in their accuracy in detecting stress from nonverbal cues. Findings suggest that the accuracy with which individuals were able to detect stress was linked to the number of social connections they reported to have. However, this association was non-linear, with individuals who were most and least accurate reporting the least network connections. This could indicate that the ability to read behaviour is associated with an ability to form and maintain social networks.

Vocal stress associated with a translocation of a family herd of African elephants (Loxodonta africana) in the Kruger National Park, South Africa

We used vocal indicators to examine the effect of a translocation of an African elephant family herd within the Kruger National Park. These animals were moved 300 km from their home range, but returned unaided to this range within 23 days. We found that translocation resulted in a change in the mean fundamental frequency of low-frequency elephant vocalizations, known as rumbles. The rumbles increased significantly in pitch compared with pre-translocation levels during the 23 days the animals spent outside their normal home range. Mean fundamental frequency returned close to pre-translocation level by the time the animals had navigated their way back to their previous home range. Raised pitch is known to be an indicator of stress in humans and other animals. The observed acoustic results are consistent with a physiological measure of stress, faecal glucocorticoid metabolite levels, which were monitored from the same animals during the study and have already been reported elsewhere. To our knowledge, this is the first report of prolonged monitoring of vocal stress response in free-ranging animals. Measuring behavioural responses, such as vocalizations, may provide an objective non-invasive method for assessing stress. This could help in determining the effects that particular management actions might have on elephants.

ChemInform Abstract: Beyond Prostaglandins — Chemistry and Biology of Cyclic Oxygenated Metabolites Formed by Free‐Radical Pathways from Polyunsaturated Fatty Acids

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Is allantoin in serum and urine a useful indicator of exercise-induced oxidative stress in humans?

To assess whether allantoin levels in serum and urine are influenced by exhaustive and moderate exercise and whether allantoin is a useful indicator of exercise-induced oxidative stress in humans, we made subjects perform exhaustive and moderate (100% and 40% VO2max) cycling exercise and examined the levels of allantoin, thiobarbituric acid reactive substances (TBARS) and urate in serum and urine. Immediately after exercise at 100% VO2max, the serum allantoin/urate ratio was significantly elevated compared with the resting levels while the serum urate levels was significantly elevated 30 min after exercise. The serum TBARS levels did not increase significantly compared with the resting levels. Urinary allantoin excretion significantly increased during 60 min of recovery after exercise, however, urinary urate excretion decreased significantly during the same period. The urinary allantoin/urate ratio also rapidly increased during 60 min of recovery after exercise. Urinary TBARS excretion decreased during the first 60 min of the recovery period and thereafter significantly increased during the latter half of the recovery period. On the contrary, after 40% VO2max of exercise, no significant changes in the levels of urate, allantoin and TBARS in serum or urine were observed. These findings suggest that allantoin levels in serum and urine may reflect the extent of oxidative stress in vivo and that the allantoin which appeared following exercise may have originated not from urate formed as a result of exercise but from urate that previously existed in the body. Furthermore, these findings support the view that allantoin in serum and urine is a more sensitive and reliable indicator of in vivo oxidative stress than lipid peroxidation products measured as TBARS.

The effect of stressful behavioural exposure on endocrine and immune parameters in the rat

AbstractStress and depression are associated with a variety of alterations in the endocrine and immune systems. Leucocyte adhesiveness/aggregation (LAA) has recently been proposed as a simple indicator of stress in humans. The objective of the present study was to examine the serum concentration of corticosterone, neutrophil phagocytosis, lymphocyte proliferation, LAA and differential white blood cell (WBC) count in rats at different time intervals following an exposure to the behavioural despair and ‘open field’ tests. Thirty min following exposure to the behavioural despair test, the concentration of corticosterone was significantly elevated. An increase in the percentage of neutrophils and LAA, and a decrease in the percentage of lymphocytes and monocytes in the WBC count, were also found 30 min and 60 min after exposure to both the behavioural despair and ‘open field’ tests. A reduction in neutrophil phagocytosis was also observed 60 min after the exposure to these situations. The results show that there are endocrine and immune changes following exposure to these experimental situations. LAA appears to be a particularly useful indicator of acute stress in rats.