Children With Cardiac Disease and Heat Exposure: Catastrophic Converging Consequences?

The detrimental impact of extreme heat exposure on the health and well-being of children is widely acknowledged. The direct and indirect effects of climate change have led to an increased risk of certain cardiovascular events which may be particularly harmful to children who are born with, or develop, heart disease.

PURPOSE

To highlight the worrying paucity of investigative research aimed at differentiating how higher ambient temperatures further tax an already compromised cardiovascular system in children.

METHODS

This commentary describes basic thermoregulatory concepts relevant to the healthy pediatric population and summarizes common heart diseases observed in this population.

RESULTS

We describe how heat stress and exercise are important factors clinicians should more readily consider when treating children with heart disease. Countermeasures to physical inactivity are suggested for children, parents, clinicians, and policymakers to consider.

CONCLUSIONS

As sudden, excessive heat exposures continue to impact our rapidly warming world, vulnerable populations like children with underlying heart conditions are at greater heat health risk, especially when coupled with the negative physical activity and fitness trends observed worldwide.

Climate change effects in older people's health: A scoping review

BACKGROUND

Climate change has serious consequences for the morbidity and mortality of older adults.

OBJECTIVE

To identify the effects of climate change on older people's health.

METHODS

A scoping review was conducted following the Joanna Briggs Institute guidelines and the PRISMA-ScR checklist. Quantitative research and reports from organizations describing the effects of climate change on older people were selected.

RESULTS

Sixty-three full-text documents were selected. Heat and air pollution were the two factors that had the most negative effects on cardiovascular and respiratory morbidity and mortality in older people. Mental health and cognitive function were also affected.

CONCLUSIONS

Climate change affects several health problems in older individuals, especially high temperatures and air pollution. Nursing professionals must have the necessary skills to respond to the climate risks in older adults. More instruments are required to determine nursing competencies on climate change and the health of this population group.

PATIENT OF PUBLIC CONTRIBUTION

No patient or public contribution.

Indoor overheating: A review of vulnerabilities, causes, and strategies to prevent adverse human health outcomes during extreme heat events

The likelihood of exposure to overheated indoor environments is increasing as climate change is exacerbating the frequency and severity of hot weather and extreme heat events (EHE). Consequently, vulnerable populations will face serious health risks from indoor overheating. While the relationship between EHE and human health has been assessed in relation to outdoor temperature, indoor temperature patterns can vary markedly from those measured outside. This is because the built environment and building characteristics can act as an important modifier of indoor temperatures. In this narrative review, we examine the physiological and behavioral determinants that influence a person's susceptibility to indoor overheating. Further, we explore how the built environment, neighborhood-level factors, and building characteristics can impact exposure to excess heat and we overview how strategies to mitigate building overheating can help reduce heat-related mortality in heat-vulnerable occupants. Finally, we discuss the effectiveness of commonly recommended personal cooling strategies that aim to mitigate dangerous increases in physiological strain during exposure to high indoor temperatures during hot weather or an EHE. As global temperatures continue to rise, the need for a research agenda specifically directed at reducing the likelihood and impact of indoor overheating on human health is paramount. This includes conducting EHE simulation studies to support the development of consensus-based heat mitigation solutions and public health messaging that provides equitable protection to heat-vulnerable people exposed to high indoor temperatures.

Narrative synthesis of the effectiveness and characteristics of heart failure disease self-management support programmes

A deeper understanding of the key elements that should be included in heart failure (HF) disease self-management support (DSMS) programmes is crucial to enhance programme effectiveness and applicability to diverse settings. We investigated the characteristics and effectiveness of DSMS programmes designed to improve survival and decrease acute care readmissions for people with HF and determine the generalizability and applicability of the evidence to low- and middle-income countries (LMICs). A narrative meta-synthesis approach was used, and systematic reviews of randomized controlled trials (RCTs) of DSMS programmes were included. The Cochrane Database of Systematic Reviews, MEDLINE, and Embase were searched without language restriction and guided by the adapted Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Eight high-quality systematic reviews were identified representing 250 studies, of which 138 were unique RCTs measuring the outcomes of interest. The findings revealed statistically significant reductions in HF readmissions [relative risk (RR) range 0.64-0.85, P < 0.5, five out of six reviews], all-cause readmissions (RR range 0.85-0.95, P < 0.5, five out of six reviews), and all-cause mortality (RR range 0.67-0.87, P < 0.5, five out of five reviews). Overall, 44.2% (n = 61) of RCTs reduced acute care readmission and improved survival. Studies were categorized according to intensity (low, moderate, moderate+, and high) based on the opportunity for immediate treatment of HF instability; 29.2% (14/48) of low-intensity, 63.6% (21/33) of moderate-intensity, 40% (6/15) of moderate+-intensity, and 47.6% (20/42) of high-intensity interventions were effective. Most effective programmes used moderate-intensity (39.4%, 48%, or 50%, respectively) or high-intensity (33.3%, 36%, and 43.7%, respectively) interventions. The majority of studies (90.6%) were conducted in high-income countries. Programmes that provided opportunities for early recognition and response to HF instability were more likely to reduce acute care readmission and enhance survival. Generalizability and applicability to LMICs are clearly limited. Tailoring HF DSMS programmes to accommodate cultural, resource, and environmental challenges requires careful consideration of intervention intensity, duration of follow-up, and feasibility in low-resource settings.

Cardiovascular admission risk attributable to hot apparent temperature: a study in a rural area of northwest China

Cardiovascular disease (CVD) is the leading cause of mortality worldwide, posing a significant threat to public health. Research on the relationship between CVD and temperature has primarily focused on developed urban settings, with limited studies conducted in rural regions with lower levels of development. Additionally, compared to relative risks, attributable risks can provide more information when assessing the risk of CVD hospitalizations associated with exposure to apparent temperature (AT). Apparent temperature is a composite temperature index that takes into account both meteorological factors and temperature, providing an objective reflection of human thermal sensation. Therefore, this study investigates the impact of AT on CVD hospitalization and quantifies the burden of CVD admission in the rural areas of China. We employed the distributed lag non-linear model (DLNM) to estimate the relationship between AT and the relative risk (RR) of CVD hospitalization. Finally, we used attributable risk methods to quantify this relationship further.

Effects of Daily Mean Temperature on Daily Hospital Admissions for Coronary Artery Disease: A Retrospective Study

Purpose

Temperature changes unfavorably impact on cardiovascular disease. However, the association between temperature changes and coronary artery disease (CAD) is not well documented. This study aimed to explore the association between daily mean temperature and daily CAD hospital admissions on the southeast coast of China (Fuzhou City).

Methods

A total of 1883 CAD patients who underwent percutaneous coronary intervention between 2017 and 2019 were obtained. The severity of CAD was evaluated by the Gensini score. Distributed lag non-linear model (DLNM) combined with a quasi-Poisson regression model was used to examine the delayed effect between daily mean temperature and daily CAD hospital admissions. Stratified analyses were performed by Gensini score and severity of lesions. The relative risk (RR) with a 95% confidence interval (CI) was used to assess the relationship.

Results

Extreme cold (8°C) (RR=0.49, 95% CI: 0.25-0.99) and moderate cold (10°C) (RR=0.56, 95% CI: 0.31-0.99) daily mean temperature with a lag of 0-20 days were correlated with lower risk of daily CAD hospital admissions. Moderate heat (30°C) (RR=1.80, 95% CI: 1.01-3.20) and extreme heat (32°C) (RR=2.02, 95% CI: 1.01-4.04) daily mean temperature with a lag of 0-20 days related to a higher risk of daily CAD hospital admissions. Similar results were observed for daily mean temperature with a lag of 0-25 days. Stratified analysis showed the lagged effect of daily mean temperature (lag 0, 0-5, 0-15, 0-20, and 0-25 days) on the daily CAD hospital admissions was observed only in patients with a Gensini score ≤39 (tertile 1).

Conclusion

Cold temperatures may have a protective effect on daily CAD hospital admissions in the Fuzhou area, whereas hot temperatures can have an adverse effect.

Machine learning analysis and risk prediction of weather-sensitive mortality related to cardiovascular disease during summer in Tokyo, Japan

Climate-sensitive diseases developing from heat or cold stress threaten human health. Therefore, the future health risk induced by climate change and the aging of society need to be assessed. We developed a prediction model for mortality due to cardiovascular diseases such as myocardial infarction and cerebral infarction, which are weather or climate sensitive, using machine learning (ML) techniques. We evaluated the daily mortality of ischaemic heart disease (IHD) and cerebrovascular disease (CEV) in Tokyo and Osaka City, Japan, during summer. The significance of delayed effects of daily maximum temperature and other weather elements on mortality was previously demonstrated using a distributed lag nonlinear model. We conducted ML by a LightGBM algorithm that included specified lag days, with several temperature- and air pressure-related elements, to assess the respective mortality risks for IHD and CEV, based on training and test data for summer 2010-2019. These models were used to evaluate the effect of climate change on the risk for IHD mortality in Tokyo by applying transfer learning (TL). ML with TL predicted that the daily IHD mortality risk in Tokyo would averagely increase by 29% and 35% at the 95th and 99th percentiles, respectively, using a high-level warming-climate scenario in 2045-2055, compared to the risk simulated using ML in 2009-2019.

Effects of apparent temperature on cardiovascular disease admissions in rural areas of Linxia Hui Autonomous Prefecture

Cardiovascular disease (CVD) is a major threat to public health worldwide. The relationship between CVD and temperature has been widely reported in developed countries and regions. However, there are few studies of severe CVD in poor rural areas of developing countries. Therefore, this study aimed to explore the relationship between CVD and apparent temperature (AT) in a rural area of Linxia Hui Autonomous Prefecture, China. Daily CVD admission data and meteorological data were collected from Linxia between 2014 and 2015. The media of AT was used as the reference temperature to estimate the cumulative relative risk (RR) of CVD admission. The distributed lag non-linear models were used to examine the association between AT and cumulative RR of CVD admission at lag 0-21 days. In Linxia, high AT (20 °C) had a persistent adverse effect on cumulative RR of CVD admissions, and the RR increased with increasing lag days. Cold (- 10 °C) had a protective effect on the first and later lag days (lag 0-14 and lag 0-21). Adults (aged < 65 years) and females were more susceptible to the effects of heat than males and the elderly (aged ≥ 65 years). In Linxia, China, extremely high AT is an important risk factor for CVD hospitalizations in suburban and rural populations.

Limitations associated with thermoregulation and cardiovascular research assessing laborers performing work in the heat

PURPOSE

To quantify the current literature and limitations associated with research examining thermoregulatory and cardiovascular strain in laborers working in the heat.

METHODS

PubMed, SCOPUS, and SPORTDiscus were searched for terms related to the cardiovascular system, heat stress, and physical work. Qualifying studies included adult participants (18-65 years old), a labor-intensive environment or exercise protocol simulating a labor environment, a minimum duration of 120 min of physical work, and environmental heat stress (ambient temperature ≥26.0°C and ≥30% relative humidity). Studies included at least one of the following outcomes: pre- and peak physical work, core temperature, heart rate (HR), systolic blood pressure, diastolic blood pressure, HR variability, and rate pressure product.

RESULTS

Twenty-one out of 1559 potential studies qualified from our search. There was a total of 598 participants (mean = 28 ± 50 participants per study, range = 4-238 participants per study), which included 51 females (8.5%) and 547 males (91.5%). Of the participants, 3.8% had cardiovascular risk factors (diabetes: n = 10; hypertension: n = 13) and 96.2% were characterized as "healthy". Fifty-seven percent of the included studies were performed in a laboratory setting.

CONCLUSIONS

Studies were predominantly in men (91.5%), laboratory settings (57%), and "healthy" individuals (96.2%). To advance equity in protection against occupational heat stress and better inform future heat safety recommendations to protect all workers, future studies must focus on addressing these limitations. Employers, supervisors, and other safety stakeholders should consider these limitations while implementing current heat safety recommendations.

Non-optimal apparent temperature and cardiovascular mortality: the association in Puducherry, India between 2011 and 2020

BACKGROUND

Cardiovascular diseases (CVDs), the leading cause of death worldwide, are sensitive to temperature. In light of the reported climate change trends, it is important to understand the burden of CVDs attributable to temperature, both hot and cold. The association between CVDs and temperature is region-specific, with relatively few studies focusing on low-and middle-income countries. This study investigates this association in Puducherry, a district in southern India lying on the Bay of Bengal, for the first time.

METHODS

Using in-hospital CVD mortality data and climate data from the Indian Meteorological Department, we analyzed the association between apparent temperature (Tapp) and in-hospital CVD mortalities in Puducherry between 2011 and 2020. We used a case-crossover model with a binomial likelihood distribution combined with a distributed lag non-linear model to capture the delayed and non-linear trends over a 21-day lag period to identify the optimal temperature range for Puducherry. The results are expressed as the fraction of CVD mortalities attributable to heat and cold, defined relative to the optimal temperature. We also performed stratified analyses to explore the associations between Tapp and age-and-sex, grouped and considered together, and different types of CVDs. Sensitivity analyses were performed, including using a quasi-Poisson time-series approach.

RESULTS

We found that the optimal temperature range for Puducherry is between 30°C and 36°C with respect to CVDs. Both cold and hot non-optimal Tapp were associated with an increased risk of overall in-hospital CVD mortalities, resulting in a U-shaped association curve. Cumulatively, up to 17% of the CVD deaths could be attributable to non-optimal temperatures, with a slightly higher burden attributable to heat (9.1%) than cold (8.3%). We also found that males were more vulnerable to colder temperature; females above 60 years were more vulnerable to heat while females below 60 years were affected by both heat and cold. Mortality with cerebrovascular accidents was associated more with heat compared to cold, while ischemic heart diseases did not seem to be affected by temperature.

CONCLUSION

Both heat and cold contribute to the burden of CVDs attributable to non-optimal temperatures in the tropical Puducherry. Our study also identified the age-and-sex and CVD type differences in temperature attributable CVD mortalities. Further studies from India could identify regional associations, inform our understanding of the health implications of climate change in India and enhance the development of regional and contextual climate-health action-plans.

Cooling Effect of Urban Blue and Green Spaces: A Case Study of Changsha, China

The cooling effects of blue-green spaces on the urban heat island effect are complex and different. The purpose of this study is to simulate how the cooling effect of blue-green space changes with its size and shape. The cooling effects of 53 green patches and 28 water bodies in Changsha were extracted based on Landsat images. A surface fitting model was used to quantitatively reveal the relationship between the cooling effect of blue-green space and its size and shape. The results show that the cooling effects of blue-green spaces were enhanced with the increasing size, and then would become stable after a certain range (threshold). Certain thresholds were identified between the blue and green space areas (2.98 ha and 3.15 ha, respectively) and the cooling distance, and between the blue and green space areas (4.84 ha and 4.92 ha, respectively) and the cooling magnitude. In addition, the green space with an area of 9.08 ha and landscape shape index (LSI) of 2.97 could achieve a better cooling distance (413.46 m); and the blue space with an area of 29.4 ha and LSI of 1.75 could achieve a better cooling magnitude (5.17 °C). These findings provide useful guidelines for urban planning and improving urban livability in other regions with terrain and climate conditions similar to Changsha.

Cardiovascular Nursing and Climate Change: A Call to Action From the CSANZ Cardiovascular Nursing Council

This Call to Action aims to provide key considerations for cardiovascular nursing, related to climate and environmental impacts. Strategies to optimise nursing preparation, immediate response and adaptation to climate emergencies are crucial to ensure those at greatest risk, including First Nations peoples, are protected from potentially avoidable harm. Professionals who manage climate consequences must also understand the impact of their care on the root cause of the problem.

The Association between Apparent Temperature and Hospital Admissions for Cardiovascular Disease in Limpopo Province, South Africa

Cardiovascular diseases (CVDs) have a high disease burden both globally and in South Africa. They have also been found to be temperature-sensitive globally. The association between temperature and CVD morbidity has previously been demonstrated, but little is known about it in South Africa. It is important to understand how changes in temperature in South Africa will affect CVD morbidity, especially in rural regions, to inform public health interventions and adaptation strategies. This study aimed to determine the short-term effect of apparent temperature (T_app) on CVD hospital admissions in Mopani District, Limpopo province, South Africa. A total of 3124 CVD hospital admissions records were obtained from two hospitals from 1 June 2009 to 31 December 2016. Daily T_app was calculated using nearby weather station measurements. The association was modelled using a distributed lag non-linear model with a negative binomial regression over a 21-day lag period. The fraction of morbidity attributable to non-optimal T_app, i.e., cold (6-25 °C) and warm (27-32 °C) T_app was reported. We found an increase in the proportion of admissions due to CVDs for warm and cold T_app cumulatively over 21 days. Increasing CVD admissions due to warm T_app appeared immediately and lasted for two to four days, whereas the lag-structure for the cold effect was inconsistent. A proportion of 8.5% (95% Confidence Interval (CI): 3.1%, 13.7%) and 1.1% (95% CI: -1.4%, 3.5%) of the total CVD admissions was attributable to cold and warm temperatures, respectively. Warm and cold T_app may increase CVD admissions, suggesting that the healthcare system and community need to be prepared in the context of global temperature changes.

Mental health and the global climate crisis

AIMS

Not only is nature essential for human existence, but many of its functions and contributions are irreplaceable. Studying the impact of these changes on individuals and communities, researchers and public health officials have largely focused on physical health. Our aim is to better understand how climate change also exacerbates many social and environmental risk factors for mental health and psychosocial problems, and can lead to emotional distress, the development of new mental health conditions and a worsening situation for people already living with these conditions.

METHODS

We considered all possible direct and indirect pathways by which climate change can affect mental health. We built a framework which includes climate change-related hazards, climate change-related global environmental threats, social and environmental exposure pathways, and vulnerability factors and inequalities to derive possible mental health and psychosocial outcomes.

RESULTS

We identified five approaches to address the mental health and psychosocial impacts of climate change which we suggest should be implemented with urgency: (1) integrate climate change considerations into policies and programmes for mental health, to better prepare for and respond to the climate crisis; (2) integrate mental health and psychosocial support within policies and programmes dealing with climate change and health; (3) build upon global commitments including the Sustainable Development Goals, the Paris Agreement and the Sendai Framework for Disaster Risk Reduction; (4) implement multisectoral and community-based approaches to reduce vulnerabilities and address the mental health and psychosocial impacts of climate change; and (5) address the large gaps that exist in funding both for mental health and for responding to the health impacts of climate change.

CONCLUSIONS

There is growing evidence of the various mechanisms by which climate change is affecting mental health. Given the human impacts of climate change, mental health and psychosocial well-being need to be one of the main focuses of climate action. Therefore, countries need to dramatically accelerate their responses to climate change, including efforts to address its impacts on mental health and psychosocial well-being.

Climate change and the prevention of cardiovascular disease

Climate change is a worsening global crisis that will continue negatively impacting population health and well-being unless adaptation and mitigation interventions are rapidly implemented. Climate change-related cardiovascular disease is mediated by air pollution, increased ambient temperatures, vector-borne disease and mental health disorders. Climate change-related cardiovascular disease can be modulated by climate change adaptation; however, this process could result in significant health inequity because persons and populations of lower socioeconomic status have fewer adaptation options. Clear scientific evidence for climate change and its impact on human health have not yet resulted in the national and international impetus and policies necessary to slow climate change. As respected members of society who regularly communicate scientific evidence to patients, clinicians are well-positioned to advocate on the importance of addressing climate change. This narrative review summarizes the links between climate change and cardiovascular health, proposes actionable items clinicians and other healthcare providers can execute both in their personal life and as an advocate of climate policies, and encourages communication of the health impacts of climate change when counseling patients. Our aim is to inspire the reader to invest more time in communicating the most crucial public health issue of the 21st century to their patients.

Triggering of myocardial infarction by heat exposure is modified by medication intake

Acute myocardial infarction (MI) can be triggered by heat exposure, but it remains unknown whether patients taking certain cardiovascular medications have elevated vulnerability. Based on a validated and complete registration of all 2,494 MI cases in Augsburg, Germany, during warm seasons (May to September) from 2001 to 2014, here we show that heat-related non-fatal MI risk was elevated among users of anti-platelet medication and beta-receptor blockers, respectively, but not among non-users, with significant differences between users and non-users. We also found that these effect modifications were stronger among younger patients (25-59 years), who had a lower prevalence of pre-existing coronary heart disease (CHD, a potential confounder by indication), than among older patients (60-74 years), who had a higher prevalence of pre-existing CHD. Users of these medications may be more vulnerable than non-users to non-fatal MI risk due to heat exposure. Further research is needed to disentangle effect modification by medication use from effect modification by pre-existing CHD.

The inequality labor loss risk from future urban warming and adaptation strategies

Heat-induced labor loss is a major economic cost related to climate change. Here, we use hourly heat stress data modeled with a regional climate model to investigate the heat-induced labor loss in 231 Chinese cities. Results indicate that future urban heat stress is projected to cause an increase in labor losses exceeding 0.20% of the total account gross domestic product (GDP) per year by the 2050s relative to the 2010s. In this process, certain lower-paid sectors could be disproportionately impacted. The implementation of various urban adaptation strategies could offset 10% of the additional economic loss per year and help reduce the inequality-related impact on lower-paid sectors. So future urban warming can not only damage cities as a whole but can also contribute to income inequality. The implication of adaptation strategies should be considered in regard to not only cooling requirements but also environmental justice.

New study investigates heat-induced labor loss in 231 Chinese cities, finding that lower-paid sectors could be disproportionately affected in coming decades, although adaptation measures may mitigate inequality related impacts.

Heat exposure and cardiovascular health outcomes: a systematic review and meta-analysis

BACKGROUND

Heat exposure is an important but underappreciated risk factor contributing to cardiovascular disease. Warming temperatures might therefore pose substantial challenges to population health, especially in a rapidly aging population. To address a potential increase in the burden of cardiovascular disease, a better understanding of the effects of ambient heat on different types of cardiovascular disease and factors contributing to vulnerability is required, especially in the context of climate change. This study reviews the current epidemiological evidence linking heat exposures (both high temperatures and heatwaves) with cardiovascular disease outcomes, including mortality and morbidity.

METHODS

In this systematic review and meta-analysis, we searched PubMed, Embase, and Scopus for literature published between Jan 1, 1990, and March 10, 2022, and evaluated the quality of the evidence following the Navigation Guide Criteria. We included original research on independent study populations in which the exposure metric was high temperatures or heatwaves, and observational studies using ecological time series, case crossover, or case series study designs comparing risks over different exposures or time periods. Reviews, commentaries, grey literature, and studies that examined only seasonal effects without explicitly considering temperature were excluded. The risk estimates were derived from included articles and if insufficient data were available we contacted the authors to provide clarification. We did a random-effects meta-analysis to pool the relative risk (RR) of the association between high temperatures and heatwaves and cardiovascular disease outcomes. The study protocol was registered with PROSPERO (CRD42021232601).

FINDINGS

In total, 7360 results were returned from our search of which we included 282 articles in the systematic review, and of which 266 were eligible for the meta-analysis. There was substantial heterogeneity for both mortality (high temperatures: I²=93·6%, p<0·0001; heatwaves: I²=98·9%, p<0·0001) and morbidity (high temperatures: I²=98·8%, p<0·0001; heatwaves: I²=83·5%, p<0·0001). Despite the heterogeneity in environmental conditions and population dynamics among the reviewed studies, results showed that a 1°C increase in temperature was positively associated with cardiovascular disease-related mortality across all considered diagnoses. The overall risk of cardiovascular disease-related mortality increased by 2·1% (RR 1·021 [95%CI 1·020-1·023]), with the highest specific disease risk being for stroke and coronary heart disease. A 1°C temperature rise was also associated with a significant increase in morbidity due to arrhythmias and cardiac arrest and coronary heart disease. Our findings suggest heat exposure leads to elevated risk of morbidity and mortality for women, people 65 years and older, individuals living in tropical climates, and those in countries of lower-middle income. Heatwaves were also significantly associated with a 17% increase in risk of mortality (RR 1·117 [95% CI 1·093-1·141]), and increasing heatwave intensity with an increasing risk (RR 1·067 [95% CI 1·056-1·078] for low intensity, 1·088 [1·058-1·119] for middle intensity, and 1·189 [1·109-1·269] for high intensity settings).

INTERPRETATION

This review strengthens the evidence on the increase in cardiovascular disease risk due to ambient heat exposures in different climate zones. The widespread prevalence of exposure to hot temperatures, in conjunction with an increase in the proportion of older people in the population, might result in a rise in poor cardiovascular disease health outcomes associated with a warming climate. Evidence-based prevention measures are needed to attenuate peaks in cardiovascular events during hot spells, thereby lowering the worldwide total heat-related burden of cardiovascular disease-related morbidity and death.

FUNDING

Australian Research Council Discovery Program.

Semiparametric Permutation-Based Change Point Detection with an Application on Chicago Cardiovascular Mortality Data

Climate change has several negative effects on health, including cardiovascular disease. Many studies have considered the effect of temperature on cardiovascular disease and found that there is an association between extreme levels of temperature, cold and hot, and cardiovascular disease. However, the number of articles that have studied the change point or the threshold in temperature is very limited. To the best of our knowledge, there have been no studies focusing on detecting and testing the significance of the change point in the temperature–cardiovascular relationship. Identifying the change point in cities may help to design better adaptive strategies in view of predicted weather changes in the future. Knowing the change points of temperature may prevent further mortality associated with the weather changes. Therefore, in this paper, we propose a unified approach that simultaneously estimates the semiparametric relationship and detects the significant point. A semiparametric generalized change point single index model is introduced as our unified approach by adjusting for several weather variables. A permutation-based testing procedure to detect the change point is introduced as well. A simulation study is conducted to evaluate the proposed algorithm. The advantage of our proposed approach is demonstrated using the cardiovascular mortality data of the city of Chicago, USA.

Travelling with heart failure: risk assessment and practical recommendations

Patients with heart failure are at a higher risk of cardiovascular events compared with the general population, particularly during domestic or international travel. Patients with heart failure should adhere to specific recommendations during travel to lower their risk of developing heart failure symptoms. In this Review, we aim to provide clinicians with a set of guidelines for patients with heart failure embarking on national or international travel. Considerations when choosing a travel destination include travel distance and time, the season upon arrival, air pollution levels, jet lag and altitude level because all these factors can increase the risk of symptom development in patients with heart failure. In particular, volume depletion is of major concern while travelling given that it can contribute to worsening heart failure symptoms. Pre-travel risk assessment should be performed by a clinician 4-6 weeks before departure, and patients should receive advice on potential travel-related illness and on strategies to prevent volume depletion. Oxygen supplementation might be useful for patients who are very symptomatic. Upon arrival at the destination, potential drug-induced photosensitivity (particularly in tropical destinations) and risks associated with the local cuisine require consideration. Special recommendations are needed for patients with cardiac implantable electronic devices or left ventricular assist devices as well as for those who have undergone major cardiac surgery.

Occupational Health Problems among Seasonal and Migrant Farmworkers in Ethiopia: A Cross-Sectional Study

Background

Migrant and seasonal farmworkers are at increased risk for occupational fatalities and injuries. Although such employment-related geographical mobility is receiving increasing attention, there is limited evidence about occupational health problems among seasonal farmworkers. Therefore, this study aims to investigate occupational health problems among seasonal and migrant farmworkers in Ethiopia.

Methods

A cross-sectional study design was employed from October to December 2019 among seasonal and migrant farmworkers. The study was carried out in two sites of Amhara regional state, northwest Ethiopia. A cluster sampling technique was used to recruit 990 study participants. Bivariable and multivariable binary logistic regression analyses were performed using SPSS version 20 to identify factors associated with injuries. The significance level was obtained at 95% CI and p-value ≤0.05.

Results

In this study, the period prevalence of work-related injury among seasonal and migrant farmworkers was 32.5% (95% CI: 29.7, 35.9). Being unemployed before migration (AOR = 2.22, 95% CI: 1.26, 3.91), working for >8 h/day (AOR = 1.62, 95% CI: 1.16, 2.27), stress (AOR = 1.38, 95% CI: 1.02, 1.88) and thermal discomfort (AOR = 1.48, 95% CI: 1.09, 1.98) were the significant risk factors for work-related injury. In addition, nearly two-third (60.9%) of the study participants have shown three or more heat-related illness symptoms. Moreover, the prevalence of work-related stress among seasonal and migrant farmworkers was 67.6% (95% CI: 64.6, 70.7).

Conclusion

Occupational health problems among seasonal and migrant farmworkers in northwest Ethiopia remain a major public health problem. Hence, implementing tailored preventive measures like training on health and safety, and hazard control measures would be supremely important to minimize the risk.

A unifying model to estimate the effect of heat stress in the human innate immunity during physical activities

Public health is threatened by climate change and extreme temperature events worldwide. Differences in health predispositions, access to cooling infrastructure and occupation raises an issue of heat-related health inequality in those vulnerable and disadvantaged demographic groups. To address these issues, a comprehensive understanding of the effect of elevated body temperatures on human biological systems and overall health is urgently needed. In this paper we look at the inner workings of the human innate immunity under exposure to heat stress induced through exposure to environment and physical exertion. We couple two experimentally validated computational models: the innate immune system and thermal regulation of the human body. We first study the dynamics of critical indicators of innate immunity as a function of human core temperature. Next, we identify environmental and physical activity regimes that lead to core temperature levels that can potentially compromise the performance of the human innate immunity. Finally, to take into account the response of innate immunity to various intensities of physical activities, we utilise the dynamic core temperatures generated by a thermal regulation model. We compare the dynamics of all key players of the innate immunity for a variety of stresses like running a marathon, doing construction work, and leisure walking at speed of 4 km/h, all in the setting of a hot and humid tropical climate such as present in Singapore. We find that exposure to moderate heat stress leading to core temperatures within the mild febrile range (37, 38][Formula: see text], nudges the innate immune system into activation and improves the efficiency of its response. Overheating corresponding to core temperatures beyond 38[Formula: see text], however, has detrimental effects on the performance of the innate immune system, as it further induces inflammation, which causes a series of reactions that may lead to the non-resolution of the ongoing inflammation. Among the three physical activities considered in our simulated scenarios (marathon, construction work, and walking), marathon induces the highest level of inflammation that challenges the innate immune response with its resolution. Our study advances the current state of research towards understanding the implications of heat exposure for such an essential physiological system as the innate immunity. Although we find that among considered physical activities, a marathon of 2 h and 46 min induces the highest level of inflammation, it must be noted that construction work done on a daily basis under the hot and humid tropical climate, can produce a continuous level of inflammation triggering moieties stretched at a longer timeline beating the negative effects of running a marathon. Our study demonstrates that the performance of the innate immune system can be severely compromised by the exposure to heat stress and physical exertion. This poses significant risks to health especially to those with limited access to cooling infrastructures. This is due in part to having low income, or having to work on outdoor settings, which is the case for construction workers. These risks to public health should be addressed through individual and population-level measures via behavioural adaptation and provision of the cooling infrastructure in outdoor environments.

Heat stress aggravates oxidative stress, apoptosis, and endoplasmic reticulum stress in the cerebellum of male C57 mice

BACKGROUND

The current study was set to assess the effect of heat stress exposure on oxidative stress, apoptosis, and endoplasmic reticulum stress markers in the cerebellum of male mice.

METHODS

Fifty male C57BL/6 mice were assigned to five groups of (I) control, (II) heat stress (HS)7, (III) HS14, (IV) HS21, and (V) HS42 groups. Animals in the control group were not exposed to HS. Mice in the II-V groups were exposed to HS once a day over 7, 14, 21, and 42 days, respectively. Cerebellar reactive oxygen species (ROS) levels, expression of heat shock protein (HSP)70 and caspase 3 as well as endoplasmic reticulum stress-related proteins (PERK, p-PERK, CHOP, and Full-length ATF-6) expression were determined on the 7th, 14th, 21st, and 42nd days.

RESULTS

ROS levels and HSP70 expression increased following HS on the 14th, 21st, and 42nd days and the 7th, and 14th days with a peak level of expression on the 14th day following HS. HSP70 levels decreased afterward on the 21st and 42nd days compared with the control group. Besides, exposure to HS for 14, 21, and 42 days resulted in a significant increase in the CHOP and p-PERK levels in the cerebellum compared with the control group. Heat exposure also increased protein expression of cleaved caspase 3 and active ATF-6/Full-length ATF-6 on the 21st and 42nd days in the cerebellum compared with the control animals.

CONCLUSION

These findings indicated that chronic HS augmented oxidative stress, endoplasmic reticulum stress, and apoptosis pathways in the cerebellum of mice.

Ambient extreme heat exposure in summer and transitional months and emergency department visits and hospital admissions due to pregnancy complications

Although extreme heat exposure (EHE) was reported to be associated with increased risks of multiple diseases, little is known about the effects of EHE on pregnancy complications. We examined the EHE-pregnancy complications associations by lag days, subtypes, sociodemographic characteristics, and areas in New York State (NYS). We conducted a case-crossover analysis to assess the EHE-pregnancy complications associations in summer (June-August) and transitional months (May and September). All emergency department (ED) visits and hospital admissions due to pregnancy complications (ICD 9 codes: 630-649) from 2005 to 2013 in NYS were included. Daily mean temperature > 90th percentile of the monthly mean temperature in each county was defined as an EHE. We used conditional logistic regression while controlling for other weather factors, air pollutants and holidays to assess the EHE-pregnancy complications associations. EHE was significantly associated with increased ED visits for pregnancy complications in summer (ORs ranged: 1.01-1.04 from lag days 0-5). There was also a significant and stronger association in transitional months (ORs ranged: 1.02-1.06, Lag 0). Furthermore, we found EHE affected multiple subtypes of pregnancy complications, including threatened/spontaneous abortion, renal diseases, infectious diseases, diabetes, and hypertension (ORs range: 1.13-1.90) during transitional months. A significant concentration response effect between the number of consecutive days of EHE and ED visits in summer (P for trend <0.001), ED visits in September (P for trend =0.03), and hospital admission in May (P for trend<0.001) due to pregnancy complications was observed, respectively. African Americans and residents in lower socioeconomic position (SEP) counties were more susceptible to the effects of EHE. In conclusion, we found an immediate and prolonged effect of EHE on pregnancy complications in summer and a stronger, immediate effect in transitional months. These effects were stronger in African Americans and counties with lower SEP. Earlier warnings regarding extreme heat are recommended to decrease pregnancy complications.

Cardiovascular Risk Prediction, Glycemic Control, and Determinants in Diabetic and Hypertensive Patients in Massawa Hospital, Eritrea: Cross-Sectional Study on 600 Subjects

BACKGROUND

Hypertension and diabetes are key determinants of cardiovascular risks. The objective of this study was to calculate 10-year incidence of cardiovascular risk, determine cardiovascular risk factors, and evaluate how diabetes and hypertension are controlled in patients in Massawa Hospital, Eritrea.

METHODS

This was a hospital-based cross-sectional study using census sampling. A checklist and interview were used as data-collection tool from October 10 to November 20, 2020. Written consent was obtained from each study participant before starting the study. Descriptive statistics were wasused, and results are presented in percentages in tables, p<0.05 was considered significant.

RESULTS

A total of 600 patients were enrolled in the study, dominated by the Tigrigna (58.7%) and Tigre (26.7%) ethnic groups. About half the patients (58.8%) had a body-mass index of 18-25 kg/m², with abdominal circumference of <95 cm (74%). Most (93.5%) patients had <10% risk of cardiovascular complications in the coming 10 years. Age showed significant association with hypertension, diabetes mellitus, cardiovascular risk, and poor glycemic and blood-pressure control (p<0.001). Body-mass index, abdominal obesity, and history of stroke were associated with hypertension and diabetes mellitus (p<0.001). Moreover, smoking, hypertension, and monthly income were associated with higher cardiovascular risk (p<0.001). In addition, hypertension and abdominal obesity were associated with glycemic control (p<0.001), and blood-pressure control was significantly associated with diabetes and hypertension (p<0.001).

CONCLUSION

Age and hypertension were associated with diabetes, cardiovascular risk and poor glycemic control, and smoking, abdominal obesity, and monthly income also significant associations with higher cardiovascular risk and glycemic control. Cessation and adjustment of modifiable factors, such as smoking, hypertension, and regular exercise are highly recommended.

The influence of climate change on skin cancer incidence - A review of the evidence

BACKGROUND

Climate change is broadly affecting human health, with grave concern that continued warming of the earth's atmosphere will result is serious harm. Since the mid-20th century, skin cancer incidence rates have risen at an alarming rate worldwide.

OBJECTIVE

This review examines the relationship between climate change and cutaneous carcinogenesis.

METHODS

A literature review used the National Institutes of Health databases (PubMed and Medline), the Surveillance, Epidemiology, and End Results and International Agency for Research on Cancer registries, and published reports by federal and international agencies and consortia, including the Australian Institute of Health and Welfare, Climate and Clean Air Coalition, U.S. Environmental Protection Agency, Intergovernmental Panel on Climate Change, National Aeronautics and Space Administration, National Oceanic and Atmospheric Administration, United Nations Environment Programme, World Health Organization, and World Meteorological Organization.

RESULTS

Skin cancer risk is determined by multiple factors, with exposure to ultraviolet radiation being the most important. Strong circumstantial evidence supports the hypothesis that factors related to climate change, including stratospheric ozone depletion, global warming, and ambient air pollution, have likely contributed to the increasing incidence of cutaneous malignancy globally and will continue to impose a negative on influence skin cancer incidence for many decades to come.

CONCLUSION

Because much of the data are based on animal studies and computer simulations, establishing a direct and definitive link remains challenging. More epidemiologic studies are needed to prove causality in skin cancer, but the evidence for overall harm to human health as a direct result of climate change is clear. Global action to mitigate these negative impacts to humans and the environment is imperative.

Association between extreme precipitation and ischemic stroke in Hefei, China: Hospitalization risk and disease burden

BACKGROUND

Ischemic stroke is an acute cardiovascular disease with high disability and mortality. Extreme precipitation has been reported to increase the risk of some cardiovascular diseases and further increase the burden of disease. At present, no studies have evaluated the relationship between extreme precipitation and ischemic stroke.

OBJECTIVE

The aim of this study was to quantitatively analyze the association between extreme precipitation and ischemic stroke hospitalizations and further explore disease burden and its associated susceptible population.

METHODS

In this study, we used Poisson generalized linear model combined with distributed lag nonlinear model to investigate the relationship between extreme precipitation (≥95th percentile) and ischemic stroke and further explored the lag effect of extreme precipitation for population with different individual characteristics.

RESULTS

Ischemic stroke hospitalizations were significantly associated with extreme precipitation. The single-day effect occurred on lag 3 (RR = 1.040, 95% CI: 1.058-1.073) lasted until lag 8 (RR = 1.036, 95% CI: 1.004-1.068). The cumulative lag effects of extreme precipitation on ischemic stroke lasted six days (lag 6-lag 11). Male and people aged ≥65 years were more sensitive to extreme precipitation. The attributable fraction (AF) and numbers (AN) of extreme precipitation on hospitalizations for ischemic stroke were 1.38% and 236.4, respectively.

CONCLUSION

Our study suggested that extreme precipitation may increase the risk of hospital admissions for ischemic stroke, emphasizing the need for society and families to pay more attention to male and people aged ≥65 years.

Controlling and preventing climate-sensitive noncommunicable diseases in urban sub-Saharan Africa

Research continues to highlight the link between climate change and health outcomes. There is, however, limited evidence in research, policies and in the Sustainable Development Goals (SDGs) about the impact of environmental factors on noncommunicable diseases (NCDs) for people living in urban areas of sub-Saharan Africa (SSA). Important is that 80% of NCDs are taking place in low- and middle-income countries (LMICs) and linked to a third of the deaths in SSA. The question is, what would these statistics look like if environmental risk factors (e.g., pollution, chemicals) for NCDs, linked to climate change, were prevented and controlled. This article presents a framework for understanding climatic pathways' impacts on climate-sensitive NCDs and achieving the SDGs. It further explains how current global mitigation interventions in high income urban settings, with implied health co-benefits for NCD reduction (i.e., promoting use of less polluting vehicles, bicycles, walking, public transport, green spaces), experience major implementation challenges in SSA cities (i.e., too costly, lack of availability, poor road conditions, gender and cultural norms, security problems). Recommendations are made for applying this framework to control climate change impacts on NCDs and achieving the SDGs in SSA cities. These include, support for more research on the climate - NCD nexus, ensuring health professional training includes sustainable health education, and including a focus on climate change and health in primary and secondary school curricula. Further recommendations for addressing climate-sensitive NCDs and urban environmental health towards achieving and sustaining the SDGs, are linked to promoting climate-sensitive and health policies and governance, as well as controlling the influence of advertising. Lastly, improving communication of research findings for policy makers and the public in a manner for informed policy making, and how to comprehend this information to promote the reduction and prevention of NCDs in urban SSA, is key.

Heat Stress Impacts on Cardiac Mortality in Nepali Migrant Workers in Qatar

Background: Qatar is a major destination country for Nepali migrant workers (NMWs; main age range 25–35 years) in the construction trade. These 120,000+ NMWs are exposed to various occupational hazards, including excessive heat, and 3–4 workers die each week. Our study aimed to show whether heat exposure caused deaths. Methods: The worker population and mortality data of NMWs were retrieved from government institutions in Nepal. Heat exposure was assessed by monthly estimates of daily wet bulb globe temperature (WBGT), for in-shade conditions, from data collected at the Doha weather station from 2009 to 2017. Working in the sun during the middle of the day would add 2–3°C to the in-shade WBGT values. Daily deaths and their causes were obtained from the records of the Foreign Employment Promotion Board (FEPB) in Nepal, 2009–2017. Interviews with returning NMWs about their working conditions and the impacts of these conditions added information. The association between the heat variable and mortality was tested with standard statistical methods. Results: The average annual death rate for NMWs in Qatar was 150 deaths/100,000. According to interviews, the majority of NMWs were found working in high WBGT (>31°C) each working day during hot months. The major cause of these deaths was recorded as cardiovascular problems (cardiovascular disease; CVD). Unfortunately, the causes of death were poorly described, and many deaths were listed as “cardiac arrest.” We included these deaths in the broader category of “cardiovascular causes.” There was a strong correlation between average monthly afternoon heat levels (WBGT) and CVD mortality. It is likely that a large proportion of these CVD deaths during hot months were due to serious heat stroke. Global studies show that approximately 15% of deaths in the age group 25–35 years are due to CVD causes. However, in this NMW population, the figures were 22% during the cool season and 58% during the hot season. Conclusions: The increased CVD mortality during hot periods is most likely due to severe heat stress. As many as 200 of the 571 CVD deaths during 2009–2017 could have been prevented if effective heat protection had been implemented as a part of local occupational health and safety programs. There is an urgent need for protection against such heat effects among NMWs, and rising temperatures from ongoing climate change are further increasing the health risks. Cause of death records for workers dying in hot conditions should be more precise than “cardiac arrest.”

Cardio-metabolic disease risk factors among South Asian labour migrants to the Middle East: a scoping review and policy analysis

This paper aims to explore the burgeoning burden of cardiovascular and metabolic disease (CMD) risk factors among South Asian labor migrants to the Middle East. We conducted a qualitative synthesis of literature using PubMed/Medline and grey literature searches, supplemented by a policy review of policies from the South Asian countries. We found a high burden of cardio-metabolic risk factors among the migrants as well as among the populations in the home and the host countries. For example, two studies reported the prevalence of diabetes mellitus (DM) ranging between 9 and 17% among South Asian migrants. Overweight and obesity were highly prevalent amongst South Asian male migrants; prevalence ranged from 30 to 66% (overweight) and 17-80% (obesity) respectively. The home country population had a significant CMD risk factor burden. Nearly 14 to 40% have three or more risk factors: such as hypertension (17 to 37%), diabetes (3 to 7%), overweight (18 to 41%), and obesity (2 to 15%). The host country also exhibited similar burden of risk factors: hypertension (13 to 38%), diabetes (8 to 17%), overweight (33 to 77%) and obesity (35 to 41%). Only Nepal, Bangladesh and Sri Lanka have some provisions related to screening of CMDs before labor migration. Further, analysis of policy papers showed that none of the reviewed documents had requirements for screening of any specific CMDs, but chronic diseases were used generically, failing to specify specific screening target. Given the high burden of risk factors, migrants' health should become an urgent priority. The lack of specific focus on screening during different stages of labor migration should receive attention. The International Labour Organization and the International Office for Migration, through their country coordination teams should engage local stakeholders to create policies and plans to address this concern. Similarly, there is a need for the host country to become an equal partner in these efforts, as migrant's better cardiometabolic health is in the benefit of both host and home countries.

Association between heat stroke and ischemic heart disease: A national longitudinal cohort study in Taiwan

The purpose of this study is to determine the relationship between heat stroke and ischemic heart disease (IHD), in a nationwide population using a longitudinal approach. We retrospectively examined the data from the National Health Insurance Research Database (NHIRD) in Taiwan, for patients examined between 2000 and 2013. In total, 628 patients with a heat stroke episode were enrolled and matched with 1256 patients without any history of a heat stroke episode by propensity score matching at a ratio of 1:2. The mean follow-up years of the heat stroke group was 11.89 years and the mean follow up of the control group was 11.51 years. An association between heat stroke episodes and IHD (log-rank p < .001) was found in a univariate cox regression analysis. After multivariate adjustment, age, comorbidities (hypertension, diabetes, stroke), and lower insurance premiums were associated with IHD events in patients who had a heat stroke. IHD was independently associated with heat stroke following cox multivariate regression analysis and patients with a heat stroke episode had a higher incidence of IHD events compared to those without any heat stroke episode (2598.41/10⁵ person-years vs. 1286.14/10⁵ person-years, adjusted hazard ratio 3.527, 95% CI: 2.078-4.032, p < .001). The onset of IHD in patients who suffered a heat stroke was earlier than in those without a heat stroke episode (2.08 ± 3.45 vs. 3.61 ± 3.25 years, p < .001). In conclusion, clinicians should be aware about evaluating the IHD risk following a heat stroke episode in a patient.

The Holistic Effects of Climate Change on the Culture, Well-Being, and Health of the Saami, the Only Indigenous People in the European Union

PURPOSE OF REVIEW

(1) To develop a framework for understanding the holistic effects of climate change on the Saami people; (2) to summarize the scientific evidence about the primary, secondary, and tertiary effects of climate change on Saami culture and Sápmi region; and (3) to identify gaps in the knowledge of the effects of climate change on health and well-being of the Saami.

RECENT FINDINGS

The Saami health is on average similar, or slightly better compared to the health of other populations in the same area. Warming climate has already influenced Saami reindeer culture. Mental health and suicide risk partly linked to changing physical and social environments are major concerns. The lifestyle, diet, and morbidity of the Saami are changing to resemble the majority populations posing threats for the health of the Saami and making them more vulnerable to the adverse effects of climate change. Climate change is a threat for the cultural way of life of Saami. Possibilities for Saami to adapt to climate change are limited.

Outpatient clinic visits during heat waves: findings from a large family medicine clinical database

INTRODUCTION

The purpose of this study was to determine whether heat waves are associated with increased frequency of clinic visits for ICD-9 codes of illnesses traditionally associated with heat waves.

METHODS

During 4 years of family medicine clinic data between 2012 and 2016, we identified six heat wave events in San Diego County. For each heat wave event, we selected a control period in the same season that was twice as long. Scheduling a visit on a heat wave day (versus a non-heat wave day) was the primary predictor, and receiving a primary ICD-9 disease code related to heat waves was the outcome. Analyses were adjusted for age, gender, race/ethnicity and marital status.

RESULTS

Of the 5448 visits across the heat wave and control periods, 6.4% of visits (n = 346) were for heat wave-related diagnoses. Scheduling a visit on heat wave day was not associated with receiving a heat wave-related ICD code as compared with the control period (adjusted odds ratio: 1.35; 95% confidence interval: 0.86-1.36; P = 0.51).

DISCUSSION

We show that in a relatively large and demographically diverse population, patients who schedule appointments during heat waves are not being more frequently seen for diagnoses typically associated with heat waves in the acute setting. Given that heat waves are increasing in frequency due to climate change, there is an opportunity to increase utilization of primary care clinics during heat waves.

Behavioral thermoregulation in older adults with cardiovascular co-morbidities

We tested the hypotheses that older adults with cardiovascular co-morbidities will demonstrate greater changes in body temperature and exaggerated changes in blood pressure before initiating thermal behavior. We studied twelve healthy younger adults (Younger, 25 ± 4 y) and six older adults ('At Risk', 67 ± 4 y) taking prescription medications for at least two of the following conditions: hypertension, type II diabetes, hypercholesterolemia. Subjects underwent a 90-min test in which they voluntarily moved between cool (18.1 ± 1.8°C, RH: 29 ± 5%) and warm (40.2 ± 0.3°C, RH: 20 ± 0%) rooms when they felt 'too cool' (C→W) or 'too warm' (W→C). Mean skin and intestinal temperatures and blood pressure were measured. Data were analyzed as a change from pretest baseline. Changes in mean skin temperature were not different between groups at C→W (Younger: +0.2 ± 0.8°C, 'At Risk': +0.7 ± 1.8°C, P = 0.51) or W→C (Younger: +2.7 ± 0.6°C, 'At Risk': +2.9 ± 1.9°C, P = 0.53). Changes in intestinal temperature were not different at C→W (Younger: 0.0 ± 0.1°C, 'At Risk': +0.1 ± 0.2, P = 0.11), but differed at W→C (-0.1 ± 0.2°C vs. +0.1 ± 0.3°C, P = 0.02). Systolic pressure at C→W increased (Younger: +10 ± 9 mmHg, 'At Risk': +24 ± 17 mmHg) and at W→C decreased (Younger: -4 ± 13 mmHg, 'At Risk': -23 ± 19 mmHg) to a greater extent in 'At Risk' (P ≤ 0.05). Differences were also apparent for diastolic pressure at C→W (Younger: -2 ± 4 mmHg, 'At Risk': +17 ± 23 mmHg, P < 0.01), but not at W→C (Younger Y: +4 ± 13 mmHg, 'At Risk': -1 ± 6 mmHg, P = 0.29). Despite little evidence for differential control of thermal behavior, the initiation of behavior in 'at risk' older adults is preceded by exaggerated blood pressure responses.

Hemodynamic responses upon the initiation of thermoregulatory behavior in young healthy adults

We tested the hypotheses that thermoregulatory behavior is initiated before changes in blood pressure and that skin blood flow upon the initiation of behavior is reflex mediated. Ten healthy young subjects moved between 40°C and 17°C rooms when they felt 'too warm' (W→C) or 'too cool' (C→W). Blood pressure, cardiac output, skin and rectal temperatures were measured. Changes in skin blood flow between locations were not different at 2 forearm locations. One was clamped at 34°C ensuring responses were reflex controlled. The temperature of the other was not clamped ensuring responses were potentially local and/or reflex controlled. Relative to pre-test Baseline, skin temperature was not different at C→W (33.5 ± 0.7°C, P = 0.24), but was higher at W→C (36.1 ± 0.5°C, P < 0.01). Rectal temperature was different from Baseline at C→W (-0.2 ± 0.1°C, P < 0.01) and W→C (-0.2 ± 0.1°C, P < 0.01). Blood pressure was different from Baseline at C→W (+7 ± 4 mmHg, P < 0.01) and W→C (-5 ± 5 mmHg, P < 0.01). Cardiac output was not different from Baseline at C→W (-0.1 ± 0.4 L/min, P = 0.56), but higher at W→C (0.4 ± 0.4 L/min, P < 0.01). Skin blood flow between locations was not different from Baseline at C→W (clamped: -6 ± 15 PU, not clamped: -3 ± 6 PU, P = 0.46) or W→C (clamped: +21 ± 23 PU, not clamped: +29 ± 15 PU, P = 0.26). These data indicate that the initiation of thermoregulatory behavior is preceded by moderate changes in blood pressure and that skin blood flow upon the initiation of this behavior is under reflex control.