Hanns-Christian Gunga

Rising temperatures in Africa present an increasing threat to agricultural productivity and public health, particularly among subsistence farming communities reliant on rain-fed agriculture. Heat exposure can impair farmers' work capacity, disrupt harvests, and heighten health risks, especially for young children vulnerable to undernutrition. The Heat to Harvest (H2H) study investigates how environmental heat exposure influences farmers' physiological and behavioral responses, and how these in turn affect harvest yields and child nutrition. It also examines differences in labor performance and recovery between households with and without cool roof coatings, although this intervention is not the central focus. H2H is designed as a prospective cohort study nested within two Health and Demographic Surveillance Systems (HDSS) in Nouna, Burkina Faso, and Siaya, Kenya. The study integrates environmental monitoring (temperature and humidity sensors used to compute Wet Bulb Globe Temperature), biometric data (via wearables tracking heart rate, temperature, physical activity, energy expenditure, and sleep), and GPS tracking (capturing spatial mobility and labor duration). The study is embedded within a larger cluster-randomized controlled trial, facilitating comparative analysis under varying thermal conditions. Findings will provide evidence-based insights into how climate-related heat stress affects health and agricultural outcomes, supporting the development of targeted adaptation strategies to enhance resilience, health, and food security in vulnerable farming communities.

Astronauts face significant stress in space, and understanding its neurobiological basis is key to assessing risk and resilience. Analogue environments, like the Antarctic Concordia Station, replicate isolated, confined, and extreme (ICE) conditions. This study assessed brain structure changes in 25 crewmembers who spent 12 months at Concordia, with MRI scans conducted before, immediately after, and five months post-mission. The study included 25 controls scanned over a similar interval and 4 “flying phantom” individuals who were scanned at all sites. Gray matter in the temporal and parietal lobes, hippocampus, pallidum, and thalamus as well as global white matter decreased during the mission in crewmembers, with all but the thalamus returning to baseline after five months. Brain ventricle volume increased, and better sleep correlated with less brain volume loss, highlighting its potentially protective role. These findings emphasize the importance of understanding mechanisms driving brain changes, particularly with growing interest in extended space missions in ICE environments.

Optimal neuroendocrine responses are essential during hypergravity (+Gz) exposure. Peripheral skin cooling (PSC) may enhance neuroendocrine function, potentially improving +Gz resiliency and influencing leukocyte and hematologic factors. This study investigated whether PSC augments the cumulative +Gz stress index (CGSI) and shifts it toward noradrenergic dependency. Eighteen men underwent a graded +Gz profile in a crossover design, with PSC applied using Arctic Sun cooling pads. Neuroendocrine and blood profiles were assessed pre- and post-+Gz. CGSI did not differ between groups, but serum osmolality increased only in PSC (p = 0.03). In PSC, CGSI correlated with norepinephrine (p < 0.01, r = 0.71) and other markers, suggesting enhanced norepinephrine responsiveness despite similar serum levels. This response may be cardio-protective for space missions and ICU patients. Additionally, baseline serum metanephrine emerged as a potential marker for +Gz resilience, with PSC showing potential leukocytic and hematologic involvement in CGSI.

Introduction: Optimal neuroendocrine responses, particularly noradrenergic responses, are critical during hypergravity (+ Gz) exposure. Peripheral skin cooling (PSC) has the potential to enhance noradrenergic function, which could improve + Gz resiliency and may also affect leukocyte and hematologic factors. We predicted that PSC would augment cumulative + Gz stress index (CGSI) neuroendocrine, leukocyte and hematologic activity compared to controls, and that CGSI would shift to a noradrenergic dependency in PSC compared to controls. Methods 18 men in a cross-over design underwent a graded + Gz profile. PSC was applied using Arctic Sun cooling pads around the thighs with 8°C water infusion. Neuroendocrine parameters and a complete blood profile with differential were obtained before and after + Gz. CGSI was calculated as + Gz * seconds. Pre / post comparisons were made within the groups with paired t-tests and between groups with independent t-tests. Pearson's correlation analysis was performed between CGSI and neuroendocrine/leukocyte/hematological parameters. Results CSGI did not differ between groups. In both groups, all neuroendocrine, leukocyte and hematological factors changed significantly from pre to post + Gz, except for serum osmolality, which increased only in PSC (p = 0.03). In PSC, CGSI correlated with noradrenaline (p < 0.01, r = 0.71), metanephrine (p = 0.02, r = -0.54), neutrophiles (p = 0.03, r = 0.51), and thrombocytes (p = 0.04, r = 0.48), while in controls, CGSI correlated with metanephrine (p = 0.02, r = -0.54). Pre + Gz metanephrine correlated with CGSI in both groups. Discussion PSC did not confer a higher CGSI nor induce a greater neuroendocrine, leukocytic or hematologic response compared to controls. However, the increase in serum osmolality may indicate increased vasopressin activity. The strong correlations between CGSI and norepinephrine in PSC suggest that despite equal average serum levels, the responsiveness of norepinephrine is enhanced. This may serve as an optimal cardio-protective countermeasure for manned space missions and possible ICU patients. The correlations between neutrophiles and thrombocytes in PSC suggest a leukocytic and hematologic involvement in CSGI. In addition, this is the first study to demonstrate that baseline serum metanephrine may serve as a potential neuroendocrine parameter to assess + Gz resilience.

Collecting and recording physiological parameters and forwarding this data via telemedicine or remote surveys may significantly increase the health and safety of people working under extreme environmental conditions, like firefighters, mountain rescuers, disaster control employees, military personnel, etc. First, ruggedized systems, as small, lightweight, and flexible as possible, are needed to optimize the goal of increasing occupational health and safety of persons at risk and maximizing their performance during missions. Previous systems could only record a very limited number of parameters, and a few could forward the data online to return information to the user. Therefore, in order to record several meaningful, valid, and reliable physiological parameters synchronized, an extension of existing systems is required. This review highlights this problem and gives an overview of the historical development. The actual status of the systems available was listed and described comparatively. In the end, a proven, promising, and innovative solution is presented that can solve the problem and allow people to work more safely in extreme environments, which may represent the future.

Editorial: Insights in Environmental, Aviation and Space Physiology: 2022

This is the first study to investigate changes in glycocalyx elements in an endurance footrace and first study to investigate exercise-induced shedding in both sexes. This study comprised of an athlete group who finished the ultra-long distance of up to 690 km during the Yukon Arctic Ultra as well as a control group. Results indicate relevant and different shedding of glycocalyx elements heparan sulfate, hyaluronan, and syndecan CD-138. Sex, age, BMI, and covered distance appear to have an influence on the shedding. Other serum parameters indicative of stress appear to be associated with shedding.

Background: Although climate change is one of the biggest global health threats, individual-level and short-term data on direct exposure and health impacts are still scarce. Wearable electronic devices (wearables) present a potential solution to this research gap. Wearables have become widely accepted in various areas of health research for ecological momentary assessment, and some studies have used wearables in the field of climate change and health. However, these studies vary in study design, demographics, and outcome variables, and existing research has not been mapped. Objective: In this review, we aimed to map existing research on wearables used to detect direct health impacts and individual exposure during climate change–induced weather extremes, such as heat waves or wildfires. Methods: We conducted a scoping review according to the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) framework and systematically searched 6 databases (PubMed [MEDLINE], IEEE Xplore, CINAHL [EBSCOhost], WoS, Scopus, Ovid [MEDLINE], and Google Scholar). The search yielded 1871 results. Abstracts and full texts were screened by 2 reviewers (MK and IM) independently using the inclusion and exclusion criteria. The inclusion criteria comprised studies published since 2010 that used off-the-shelf wearables that were neither invasive nor obtrusive to the user in the setting of climate change–related weather extremes. Data were charted using a structured form, and the study outcomes were narratively synthesized. Results: The review included 55,284 study participants using wearables in 53 studies. Most studies were conducted in upper–middle-income and high-income countries (50/53, 94%) in urban environments (25/53, 47%) or in a climatic chamber (19/53, 36%) and assessed the health effects of heat exposure (52/53, 98%). The majority reported adverse health effects of heat exposure on sleep, physical activity, and heart rate. The remaining studies assessed occupational heat stress or compared individual- and area-level heat exposure. In total, 26% (14/53) of studies determined that all examined wearables were valid and reliable for measuring health parameters during heat exposure when compared with standard methods. Conclusions: Wearables have been used successfully in large-scale research to measure the health implications of climate change–related weather extremes. More research is needed in low-income countries and vulnerable populations with pre-existing conditions. In addition, further research could focus on the health impacts of other climate change–related conditions and the effectiveness of adaptation measures at the individual level to such weather extremes.

BACKGROUND Individual-level data on direct exposure and health impacts are scarce in the field of climate change and health. Wearable electronic devices (wearables) have become widely accepted in various areas of health research for the so-called ecological momentary assessment. OBJECTIVE We conducted this scoping review to map existing research on wearables used to detect direct health impacts and individual exposure during climate change-induced weather extremes such as heatwaves or wildfires. METHODS We conducted a scoping review and systematically searched six databases (PubMed, IEEE Xplore, CINAHL, WoS, Scopus, Ovid) and Google Scholar. A total of 1,871 references were screened. RESULTS The review comprised a total of 55,284 study participants using wearables in 53 studies. Most studies were conducted in upper-middle and high-income countries (50/53; 94%) in urban environments (25/53; 47%) or in a climatic chamber (19/53; 36%) and assessed health effects of heat exposure (52/53; 98%). The majority found adverse health effects of heat exposure on sleep, physical activity, and heart rate. Remaining studies assessed occupational heat stress or compared individual and area-level heat exposure. Fourteen studies (14/53; 26%) determined that all examined wearables were valid and reliable for measuring health parameters during heat exposure when compared to standard methods. CONCLUSIONS Wearables have been utilized successfully in large-scale research to measure the health implications of climate change-related weather extremes. Further research is needed in low-income countries and vulnerable populations with pre-existing conditions.