Physiological Stress Indicators Research Articles

Enhancing quality assessment of live Pacific oysters (Crassostrea gigas) using flexible sensors real‐time monitoring physiological signals

AbstractShell‐closing strength (SCS) is commonly used to assess oyster vigor and quality as an important physiological stress indicator of the oyster organism. In this study, a quality decision support system based on flexible wireless sensor network and web services was designed and developed to explore the application of SCS in the rapid assessment of vitality and quality. Based on physiological and environmental information collected by flexible wireless sensor networks, this study proposes a novel quantitative vitality assessment method to identify oyster life decline cycles and processes. Meanwhile, TVB‐N, TVC, and pH were selected as quality indicators, and a back‐propagation artificial neural network (BP‐ANN) was used to predict and evaluate oyster quality indicators. The results showed that the root mean square errors (RMSE) for TVB‐N, TVC, and pH were 0.4624, 0.8827, and 0.1941; the coefficients of determination (R2) were 0.8919, 0.8578, and 0.6249. Therefore, the rapid assessment of oyster vitality and quality based on a flexible wireless sensor network is a reliable and effective means.Practical applicationsThis study aims to explore the application of live oyster SCS for rapid quality evaluation. In this article, a quality decision support system based on a flexible wireless sensor network (WSN) and web services is developed to improve the quality and health of live oysters in the supply chain. The use of the multi‐sensor system enables the monitoring and collection of environmental and physiological signals of live oysters throughout the supply chain process. The evaluation of the quality of live oysters using physiological and environmental information collected by flexible wireless sensor networks is a reliable and efficient method. This will provide an effective and reliable quality evaluation and management for the oyster industry.

Analysis of the Effect and Efficiency of Tension-Free Hernia Repair and Traditional Surgery in The Treatment of Hernia

Objective: To analyze the efficiency of tension-free hernia repair and traditional surgery in the treatment of hernia. Methods: A total of 80 patients with hernias were selected and randomly into a control group (traditional hernia repair) and an observation group (tension-free hernia repair), of 40 cases each. The perioperative indicators, pain, physiological stress indicators, complications, and recurrence rates between the two groups were compared. Results: The perioperative indexes of the observation group were better than those of the control group (P < 0.05). The postoperative pain score, postoperative physiological stress index level, incidence of complications, and recurrence rate of the observation group were lower than those of the control group (P < 0.05). Conclusion: In the surgical treatment of hernia, tension-free hernia repair was less traumatic and had a better effect than traditional hernia repair.

Growth, body composition, lipid profile, and peroxidation, physiological stress, and blood metabolic indicators in Labeo rohita fed a fish oil replacement with blended linseed and sunflower oils

Growth, body composition, lipid profile, and peroxidation, physiological stress, and blood metabolic indicators in Labeo rohita fed a fish oil replacement with blended linseed and sunflower oils

Mapping pathways to neuronal atrophy in healthy, mid-aged adults: From chronic stress to systemic inflammation to neurodegeneration?

Growing evidence implicates systemic inflammation in the loss of structural brain integrity in natural ageing and disorder development. Chronic stress and glucocorticoid exposure can potentiate inflammatory processes and may also be linked to neuronal atrophy, particularly in the hippocampus and the human neocortex. To improve understanding of emerging maladaptive interactions between stress and inflammation, this study examined evidence for glucocorticoid- and inflammation-mediated neurodegeneration in healthy mid-aged adults.N = 169 healthy adults (mean age = 39.4, 64.5% female) were sampled from the general population in the context of the ReSource Project. Stress, inflammation and neuronal atrophy were quantified using physiological indices of chronic stress (hair cortisol (HCC) and cortisone (HEC) concentration), systemic inflammation (interleukin-6 (IL-6), high-sensitive C-reactive protein (hs-CRP)), the systemic inflammation index (SII), hippocampal volume (HCV) and cortical thickness (CT) in regions of interest. Structural equation models were used to examine evidence for pathways from stress and inflammation to neuronal atrophy. Model fit indices indicated good representation of stress, inflammation, and neurological data through the constructed models (CT model: robust RMSEA = 0.041, robust χ2 = 910.90; HCV model: robust RMSEA <0.001, robust χ2 = 40.95). Among inflammatory indices, only the SII was positively associated with hair cortisol as one indicator of chronic stress (β = 0.18, p < 0.05). Direct and indirect pathways from chronic stress and systemic inflammation to cortical thickness or hippocampal volume were non-significant. In exploratory analysis, the SII was inversely related to mean cortical thickness.Our results emphasize the importance of considering the multidimensionality of systemic inflammation and chronic stress, with various indicators that may represent different aspects of the systemic reaction. We conclude that inflammation and glucocorticoid-mediated neurodegeneration indicated by IL-6 and hs-CRP and HCC and HEC may only emerge during advanced ageing and disorder processes, still the SII could be a promising candidate for detecting associations between inflammation and neurodegeneration in younger and healthy samples. Future work should examine these pathways in prospective longitudinal designs, for which the present investigation serves as a baseline.

A multisite feasibility randomized clinical trial of mindfulness-based resilience training for aggression, stress, and health in law enforcement officers

BackgroundLaw enforcement officers (LEOs) are exposed to significant stressors that can impact their mental health, increasing risk of posttraumatic stress disorder, burnout, at-risk alcohol use, depression, and suicidality. Compromised LEO health can subsequently lead to aggression and excessive use of force. Mindfulness training is a promising approach for high-stress populations and has been shown to be effective in increasing resilience and improving mental health issues common among LEOs.MethodsThis multi-site, randomized, single-blind clinical feasibility trial was intended to establish optimal protocols and procedures for a future full-scale, multi-site trial assessing effects of mindfulness-based resilience training (MBRT) versus an attention control (stress management education [SME]) and a no-intervention control, on physiological, attentional, and psychological indices of stress and mental health. The current study was designed to enhance efficiency of recruitment, engagement and retention; optimize assessment, intervention training and outcome measures; and ensure fidelity to intervention protocols. Responsiveness to change over time was examined to identify the most responsive potential proximate and longer-term assessments of targeted outcomes.ResultsWe observed high feasibility of recruitment and retention, acceptability of MBRT, fidelity to assessment and intervention protocols, and responsiveness to change for a variety of putative physiological and self-report mechanism and outcome measures.ConclusionsResults of this multi-site feasibility trial set the stage for a full-scale, multi-site trial testing the efficacy of MBRT on increasing LEO health and resilience, and on decreasing more distal outcomes of aggression and excessive use of force that would have significant downstream benefits for communities they serve.Trial registrationClinicalTrials.gov, NCT03784846. Registered on December 24th, 2018.

Drought Responses in Three Apple Cultivars Using an Autonomous Sensor-based Irrigation System

Irrigation decision support systems evolving in the domestic temperate tree fruit production industry incorporate measures of soil moisture status, which diverges from classic physiological indicators of edaphic stress. This study used an autonomous sensor-based irrigation system to impose a water deficit (soil matric potential targets of –25, –40, –60, and –80 kPa) on ‘Autumn Gala’, ‘CrimsonCrisp’, and ‘Golden Delicious’ apple (Malus domestica) cultivars grafted to ‘Budagovsky 9’ rootstock in the greenhouse (n = 60). It was hypothesized that relationships between physiological plant function, assessed via infrared gas exchange and chlorophyll fluorescence, and the soil matric potential may be used to advance emerging irrigation decision support systems. Complications arising from defoliation by day 11 at –60 and –80 kPa indicate the generation of substrate-specific soil–water relationships in research applications of autonomous sensor-based irrigation systems. ‘Autumn Gala’ carbon assimilation rates at –80 kPa declined from day 0 to day 8 (9.93 and 5.86 μmol⋅m–2⋅s–1 carbon dioxide), whereas the transpiration rate was maintained, potentially reducing observed defoliation as other cultivars increased transpiration to maintain carbon assimilation. Correlation matrices revealed Pearson’s r ≤ |0.43| for all physiological metrics considered with soil matric potential. Nevertheless, exploratory regression analysis on predawn leaf water potential, carbon assimilation, transpiration, stomatal conductance, and nonphotochemical quenching exposed speculatively useful data and data shapes that warrant additional study. Nonlinear piecewise regression suggested soil matric potential may useful as a predictor for the rate of change in predawn leaf water potential upon exposure to a water deficit. The critical point bridging the linear spans, –30.6 kPa, could be useful for incorporating in emerging irrigation decision support systems.

Humic Acid Mitigates Drought Stress in Tomato

Drought stress, one of the most important abiotic stresses, severely limits global crop production. To increase tolerance to this stress, environmentally friendly practices are emphasised. Humic acid, one of the most important natural biostimulants, has positive effects on plant growth and yield. Recently, it has also been reported to play an important role in resistance to various abiotic stresses. However, many physiological and molecular mechanisms by which humic acid confers drought resistance have not been fully elucidated. Therefore, the effects of humic acid application on different morphological and physiological stress indicators and some antioxidative enzyme gene expressions of tomato seedlings under drought stress conditions were investigated in this study. It was found that drought stress decreased shoot fresh/dry weight, root fresh/dry weight, shoot and root length, chlorophyll and relative water content of plants by 67%, 56%, 31%, 38%, 22%, 20%, 15% and 25%, respectively. Humic acid application significantly increased these parameters, while reducing ion leakage, MDA and proline levels. The antioxidant enzyme gene expression of tomato seedlings under drought conditions showed no significant difference in SOD and APX gene expression, whereas CAT gene expression increased and GR gene expression decreased with humic acid application. Our results showed that humic acid application interacted with stress-related antioxidant enzyme gene expression and may be effective in reducing drought stress.

Physical injury, physiological stress, and behavior impairment of striped bass (Morone saxatilis) after catch‐and‐release by spin and fly angling

AbstractThe striped bass (Morone saxatilis) is one of the most important species for anglers along the Atlantic coast and a subject of intensive fisheries management. To promote best catch‐and‐release practices, understanding the physical and physiological consequences of angling is critical. We assessed the injury and stress of striped bass captured using rod and reel spin and fly tackle in a New England embayment. During 2010–2011, of 95 striped bass captured, only one died immediately after release. Behavioral impairment measured through reflex action mortality predictors increased when hooked in the gullet or gills. While 11.6% were critically hooked (in gills, gullet, or eyes), hooking severity was not related to terminal tackle (lure or fly). However, the most severely impaired were all hooked with J hooks. Physiological stress indicators (sodium, chloride, blood lactate) increased with longer fight times. Our results suggested that different components of an angling event drove physiological and behavioral responses.

Compromised health: Examining growth and health in a late antique Roman infant and child cemetery.

Combining research from infant and child development, public health, anthropology, and history, this research examines the relationship between growth, growth disruption, and skeletal indicators of chronic and/or episodic physiological stress (stress) among juvenile individuals (n = 60) interred at the late antique infant and child cemetery at Poggio Gramignano (PG) (ca. 5th century CE), associated with a rural agricultural community. Growth disruption-evidenced by decreased long bone length compared to dental age-and stress experience-evidenced by skeletal stress indicators-within these individuals are compared to those within juveniles from a comparative sample (n = 66) from two urban Roman-era cemeteries, Villa Rustica (VR) (0-250 CE) and Tragurium City Necropolis (TCN) (0-700 CE). Results indicate that individuals from PG had significantly smaller femoral lengths-for-age than those from VR and TCN; however, the frequency of skeletal stress indicators was higher among juveniles from VR and TCN. These differences in growth and stress experience are likely related to the different biosocial and ecological environments present in these two regions. For the community at PG, internal and external violent conflicts, as well as social, political, and economic turmoil, and subsistence shortages, endemic and epidemic infectious disease, nutritional deficiencies, and inherited or acquired anemia may have synergized to create chronically and/or episodically deleterious conditions for its juveniles.

Effects of stocking density during simulated transport on physiology and behavior of largemouth bass (Micropterus salmoides)

AbstractThe live transport of farmed fish is an important practice in Chinese aquaculture due to consumer preferences in its domestic market. However, live transport can be stressful for fish and may cause many welfare issues. This study aimed to examine the effects of transport density on the welfare of largemouth bass (Micropterus salmoides). Adult fish were allocated to four experimental treatments in a two‐factor design (N = 5 groups per treatment). Factor one was stocking density of either 39 (low density) or 78 (high density) g L−1. Factor two was transport, with half of the fish groups exposed to simulated transport stress for 3 h using a motion platform, and the other half kept in static tanks for the same length of time. Baseline behavior and physiology were determined from a subset of fish after acclimation but before selection into groups and application of transport. To determine the effects of transport, stocking density, and their interaction on the experimental groups, physiological sampling and behavioral recording were carried out immediately after simulated transport, and water quality was measured both before and after transport. Changes in water quality were observed between two timepoints, with decreased dissolved oxygen levels and increased water temperature. Total ammonia nitrogen levels significantly increased in all treatments over time, particularly in the high‐density groups. Fish ventilation rates were significantly elevated in the groups kept at a high stocking density regardless of whether they also experienced transport stress. Fish transported at a high stocking density also showed more fear‐related behaviors such as freezing and thigmotaxis than non‐transported groups. Serum cortisol, catalase, and aspartate transaminase levels were significantly higher in the transported treatment groups compared to the baseline fish, but no difference was found for serum glucose, lactate, and glutathione peroxidase. We concluded that 3 h of simulated transport was stressful to largemouth bass kept at 78 g L−1, as evidenced by altered fish physiological and behavioral indicators of stress, as well as deteriorated water quality. Additionally, we identified a positive correlation between serum and skin mucus samples for cortisol, glucose, and lactate in transported fish, providing important information for developing less invasive methods for the welfare assessment of largemouth bass.

A Relaxed Horse-A Relaxed Client? An Experimental Investigation of the Effects of Therapy Horses' Stress on Clients' Stress, Mood, and Anxiety.

Equine-assisted therapies are becoming increasingly popular for addressing physical and psychological disabilities in clients. The role of the horse's welfare in equine-assisted service receives increasing attention in research. Several studies have shown that horses are able to perceive human emotions and respond to human stress responses. However, no research has yet looked at the other side of the coin-whether and how humans perceive and react to equine stress levels during equine-assisted services. To fill this gap in the research, we employed a within-subjects design, in which horse-naïve participants had a standardized interaction with both an experimentally stressed horse and an experimentally relaxed horse. We assessed physiological indicators of stress (heart rate, heart rate variability, and salivary cortisol) in participants and horses, as well as psychological indicators of stress (state anxiety and positive and negative affect) in participants. Although our stress and relaxation manipulations were successful (indicated by horses' physiological indicators of stress), we did not find any difference in the participants' physiological or psychological indicators of stress between the interaction with a stressed and the interaction with a relaxed horse. Together with results from previous studies, this suggests that humans cannot intuitively recognize the (physiological) stress level of horses, which has important implications for effective communication and bonding between humans and horses and for the safety of equine activities.

Physiological response of Katahdin ewes to the absence of shadows in tropical region of Mexico

This study evaluated the effect of environmental conditions on the physiological and body infrared temperature traits of Katahdin sheep. Ten recently reproductive-managed ewes were randomly segregated into two groups. The control group (CG) was under outdoor conditions with shadow access, and the experimental group (EG) was under outdoor conditions without shadow access. Traits were measured for 16 days, and the environmental traits confirmed significant differences between groups, with an average temperature-humidity index (THI) of 68.64±1.46 for the CG and 72.98±3.17 for the EG, with a breach of five units between groups. The THI was subsequently used to evaluate the heat load. Respiratory frequency was the physiological variable that responded the most to heat stress. The rectal temperature of the sheep was greater in the experimental group than in the control group, indicating an increase in heat stress. The EG also presented higher heat emissions from body regions, which was associated with changes in core body temperature and blood flow at the body surface. Differences in hematological parameters, such as the erythrocyte count, mean corpuscular volume, and total plasma protein concentration, were found between the groups. Infrared thermography was found to be efficient for estimating heat stress in sheep species, and head temperature was found to be a reliable indicator of physiological thermal stress.

Effects of selling through an auction market on physiological variables in beef calves

In Chile, selling cattle through auction markets is common, and involves various stressful events. The objective of this study was to determine the effects of selling weaned beef calves through an auction market on indicators of physiological stress. Considering that transportation is invariably linked to any commercialization procedure, we compared the effects of exposing calves to transport and sale through an auction market versus transporting them directly between farms. Twenty calves of 175 (+/-37.5) kg live weight were transported from their origin farm to an auction market (2.5 h journey), where 10 calves were unloaded and exposed to regular handling within the market (unloading, sorting, regrouping, penning, sale yard showing) and thereafter loaded and transported back to the farm (TM). The remaining 10 calves were not unloaded at the market and were immediately transported back to the farm, simulating a direct sale (TD). Data collection (blood samples, body temperature, and live weight) was performed at the farm in both groups before loading (initial, 0 h), at the end of the process, after unloading TM calves back on the farm (after unloading, 12 h), and during recovery at 24, 48, and 72 h after the initial sampling. We used mixed-effects models to compare treatments and samplings. No differences were found between treatments in terms of live weight loss, maximum eye temperature, plasma beta-hydroxybutyrate, and serum cortisol concentrations. The rectal temperature was higher (p &lt; 0.05) in TM after treatment and remained higher (p &gt; 0.05) in the samples than in TD. Calves that passed through the market showed higher (p &lt; 0.05) plasma CK activity after unloading (12 h) than did those that did not. The mean glucose concentration increased (p &lt; 0.05) at 12h and remained higher than the initial value (0 h) in both the calf groups. This was a preliminary study, and according to the results, experiments should be repeated to test more animals under different situations and premises.

Marine heatwaves recurrence aggravates thermal stress in the surfgrass Phyllospadix scouleri

The surfgrass Phyllospadix scouleri grows in highly productive meadows along the Pacific coast of North America. This region has experienced increasingly severe marine heatwaves (MHWs) in recent years. Our study evaluated the impact of consecutive MHWs, simulated in mesocosms, on essential ecophysiological features of P. scouleri. Overall, our findings show that the plants' overall physiological status has been progressively declining. Interestingly, the indicators of physiological stress in photosynthesis only showed up once the initial heat exposure stopped (i.e., during the recovery period). The warming caused increased oxidative damage and a decrease in nitrate uptake rates. However, the levels of non-structural carbohydrates and relative growth rates were not affected. Our findings emphasize the significance of incorporating recovery periods in this type of study as they expose delayed stress responses. Furthermore, experiencing consecutive intense MHWs can harm surfgrasses over time, compromising the health of their meadows and the services they offer to the ecosystem.

Can a virtual human increase mindfulness and reduce stress? A randomised trial

BackgroundStress is a significant issue amongst university students, yet limited psychological services are available. Mindfulness is effective for stress reduction and can be delivered digitally to expand access to student populations. However, digital interventions often suffer from low engagement and poor adherence. A virtual human may improve engagement and adherence through its humanlike appearance and behaviours. ObjectiveTo examine whether a virtual human could reduce stress in university students at least as much as a teletherapist, and more than a chatbot, using a mindfulness intervention. MethodsStressed university students (N = 158) were randomly allocated to the virtual human (N = 54), chatbot (N = 54), or teletherapist (N = 50). 36 participants received each condition. Participants completed one lab session and were asked to do online homework sessions at least twice weekly for four weeks. Changes in self-reported stress and mindfulness, physiological stress indices, homework completion, and perceptions of the agent were compared between groups. Thematic analysis was conducted on participants’ responses to open-ended questions about the interventions. ResultsThere were significant reductions in stress and increases in mindfulness across all groups. All groups had higher peripheral skin temperature post-intervention, and only the teletherapy group had higher electrodermal activity (reflecting elevated stress) post-intervention compared to baseline. There were no significant changes in heart rate. Homework adherence was significantly higher in the virtual human group, whereas homework satisfaction and engagement were lowest in the chatbot group. Thematic analysis found that people thought the robotic voice of the virtual human could be improved, the chatbot could be improved by adding audio, and that participants experienced feelings of judgement from the teletherapist. DiscussionOverall, results support use of virtual humans for delivering mindfulness interventions in stressed students. Virtual humans may have the advantage over teletherapy and chatbots of increasing adherence in student populations, but more work is needed to increase perceived empathy and replicate results in other populations.

Effect of Blood Flow Restriction during the Rest Periods of Squats on Accuracy of Estimated Repetitions to Failure.

This study investigated the impact of resistance training with blood flow restriction during rest (BFRrest) on the accuracy of estimated repetitions to failure (ERF). It also explored associations between error in ERF and mean concentric velocity (MCV) along with physiological responses. In a randomised cross-over study, 18 male trainers (23.4 ± 2.7 years) performed three sets of squats at 70% of their one-repetition maximum until failure. One session integrated BFRrest, while another employed traditional passive inter-set rest (TRAD) during the 3 min inter-set rest intervals. Cardiorespiratory and metabolic measures were taken in the inter-set recovery periods. The results revealed no significant differences between BFRrest and TRAD in terms of ERF and error in ERF. A notable set effect for ERF was observed, with a greater ERF during set 1 compared to sets 2 and 3 (p < 0.001). Additionally, a lower error in ERF was observed during sets 2 and 3 compared to set 1 (p < 0.001). Error in ERF were strongly associated with the respiratory exchange ratio, and moderately associated with end-tidal carbon dioxide partial pressure, carbon dioxide output, and MCV variables. Notably, the precision of ERF seems to be predominantly influenced by indicators of physiological stress rather than the incorporation of BFRrest.

Harris Lines as Indicators of Physiological Stress in the Middle Holocene Cis-Baikal

This article is a plain language summary of a master’s thesis completed in 2022 through the Department of Archaeology and Anthropology at the University of Saskatchewan. The goal of this research was to study Harris lines (HL; transverse lines in human and animal long bones that are only visible through X-rays) in the skeletal remains of hunter-gatherers from the Middle Holocene (~9000–3000 years BP) Baikal region of the Russian Federation. HL have often been associated with stress events such as malnutrition or disease in early life. Thus, this thesis expected to highlight differences in the lived stress experiences of two distinct cultural periods from the region which had already been shown in previous studies on stress. Individuals 25 years and younger at time of death from two cemetery populations dating to the Early Neolithic (EN; 7560–6660 years BP) and one from the Late Neolithic (LN; 6060–4970 years BP) were examined for HL. The data was then compared between EN and LN individuals to determine if one population experienced greater stress than the other based on higher HL counts. This thesis demonstrated that HL are not irrefutably tied to stress in EN and LN populations from the Cis-Baikal and HL are not reliable determinants of how often or how many periods of stress they experienced during development. This thesis also challenged ongoing critiques in the study of HL, including image capture methods, to facilitate future research and discussion relating to HL.

Shock Index and Physiological Stress Index for reestratifying patients with intermediate-high risk pulmonary embolism.

Study and Evaluation of Two Scores: Shock Index (SI) and Physiological Stress Index (PSI) as discriminators for proactive treatment (reperfusion before decompensated shock) in a population of intermediate-high risk pulmonary embolism (PE). Using a database from a retrospective cohort with clinical variables and the outcome variable of "proactive treatment", a comparison of the populations was conducted. Optimal cut-off for "proactive treatment" points were obtained according to the SI and PSI. Comparisons were carried out based on the cut-off points of both indices. Patients admitted to a mixed ICU for PE. Patients >18 years old admitted to the ICU with intermediate-high risk PE recruited from January 2015 to October 2022. None. Population comparison and metrics regarding predictive capacity when determining proactive treatment. SI and PSI independently have a substandard predictive capacity for discriminating patients who may benefit from an early reperfusion therapy. However, their combined use improves detection of sicker intermediate-high risk PE patients (Sensitivity = 0.66) in whom an early reperfusion therapy may improve outcomes (Specificity = 0.9). The use of the SI and PSI in patients with intermediate-high risk PE could be useful for selecting patients who would benefit from proactive treatment.

Thermal Stress Associated Serum Factors and the Influence of Weather Parameters in Crossbred Dairy Cows Under Humid Tropics

Assessment of the level of thermal stress (TS) in animals exposed to adverse weather helps to formulate and implement alleviation measures. Present study was to identify the presence and seasonal pattern of serum factors to be used as biological indicators for early detection of TS in animals. The year-round study involved eight cows each at a time, belonging 28 to 91 days postpartum, and replaced two cows every month. Analyzed the levels of Heat shock protein 70 (HSP 70) and cortisol in serum samples collected at weekly intervals and assessed the seasonal pattern and correlation with weather parameters. While minimum temperature (MnT) of the region varied significantly (P&lt;0.01) between seasons (lowest mean 22.09±1.19 ºC), maximum temperature (MxT) was consistently high across seasons (yearly mean 33.64±0.77 ºC). Moderate to high (66 to 85 %) relative humidity (RH) was prevalent year-round, mainly contributed by the extended rainy season. Temperature-humidity index (THI) of the locality exceeded 78, exposing the animals to moderate to severe TS throughout the year. HSP 70 levels varied significantly (P&lt;0.01) between seasons, with a significant hike (6.24±0.51 ng/mL) during summer (THI 83.20±0.53) and lesser elevation during other seasons of moderate THI, indicating its association with TS. Cortisol levels varied significantly (P&lt;0.01) between seasons, however there was no significant correlation with THI and other weather parameters. To conclude, while cortisol forms a general indicator of physiological stress, HSP 70 appears more specific to TS, and its usefulness for early detection of TS needs further studies.

The more the merrier? Perceived forest biodiversity promotes short‐term mental health and well‐being—A multicentre study

Abstract Forests can foster mental health and well‐being. Yet, the contribution of forest biodiversity remains unclear, and experimental research is needed to unravel pathways of biodiversity–health linkages. Here, we assess the role of tree species richness, both actual and perceived, and how stress reduction and attention restoration can serve as potential mediating pathways to achieve positive mental health and well‐being outcomes. We conducted an experimental, multicentric field study in three peri‐urban forests in Europe, employing a mixed design with 223 participants, that comprised 20‐min stays in forests with either low, medium or high tree species richness or a built control. Participants' short‐term mental health and well‐being and saliva cortisol as a biomarker of stress were measured before and after the intervention. Forest visits for 20 min were found to be beneficial for participants' short‐term mental health, short‐term mental well‐being, subjective stress, subjective directed attention and perceived restorativeness compared with a built environment. No differences were found for the physiological stress indicator saliva cortisol, which decreased in both the forest and the built environments. Increased perceived biodiversity—possibly linked to structural forest attributes—was significantly associated with well‐being outcomes, while no association was found for differences in actual tree species richness. Structural equation modelling indicates that higher levels of perceived biodiversity had an indirect effect on short‐term mental health and well‐being through enhancing perceived restorativeness. While we found no evidence of actual tree species richness effects, perceived biodiversity was associated with positive short‐term mental health and well‐being outcomes. Understanding these biodiversity–health linkages can inform conservation management and help develop effective nature‐based interventions for promoting public health through nature visits. Read the free Plain Language Summary for this article on the Journal blog.