A growing body of qualitative and quantitative research has explored the potential benefits to mental health and well-being of open-water or "wild" swimming. To date, most studies have used small samples in specific locations, limiting generalisability, and have not distinguished open-water swimming from other forms of outdoor swimming, such as in open-air pools, raising questions about any additional benefits of wild swimming over and above swimming outside per se. Using survey data from n = 1200 recently recalled outdoor swimming visits across 19 different countries, we compared self-reported well-being outcomes for swims in either open-water (wild) locations or open-air pools. Additionally, we explored the degree to which satisfaction of the motivations identified by self-determination theory (i.e. autonomy, relatedness, and competence) may explain any differences. Swimming visits in both locations were associated with high levels of positive, and low levels of negative, well-being, as well as high levels of autonomy, relatedness and competence. Open-water swimming was, nonetheless, associated with significantly higher positive well-being than open-air pool swims, with mediation analysis indicating that feelings of greater autonomy and competence (but not relatedness) primarily accounted for the difference. Results for anxiety were more nuanced, perhaps because more competent swimmers were more likely to swim in less safe, more anxiety inducing, places. Results re-iterate, help explain, and support the generalisation of previous research reporting potential benefits of open-water swimming for mental health and well-being, and highlight the need to support further safe access to high quality open-water locations.

BACKGROUND:High ambient temperatures lead to increased mortality, especially in older adults. Climate change will increase the frequency and severity of heatwaves globally. Most of the UK population lives in urban areas, which often have higher temperatures than rural areas (the urban heat island [UHI] effect) and higher rates of heat-related mortality. We estimated the mortality burden in terms of attributable mortality and years of life lost (YLLs), and social costs attributed to the UHI effect in summer 2018 in Greater London. METHODS:We estimated the UHI effect using advanced urban climate modelling. We applied a quantitative health impact assessment to estimate mortality and YLLs attributable to high air temperature. We estimated social costs using value of statistical life (VSL) and value of statistical life-years (VOLY) methods. FINDINGS:We attribute 785 (95% CI 655-919) deaths in summer 2018 in Greater London to high air temperature. Half of these (399 [350-446]) are attributable to the UHI effect, or approximately 5·0 (4·1-5·9) thousand YLLs. Social costs of the summer UHI effect due to mortality are estimated at £987 million (866 million-1·10 billion) using VSL or £453 million (367-533 million) using VOLY (2023 prices). INTERPRETATION:Monetised costs attributed to the UHI effect remain high using either VSL or VOLY approaches. The findings demonstrate the seriousness of heat as a public health risk, set a scale at which society may be willing to pay for urban heat mitigation, and give tangible support for large-scale urban heat mitigation and adaptation policies. FUNDING:Wellcome Trust.

Emerging evidence suggests that residential greenspace is associated with a lower prevalence of health risk behaviours, but it remains unclear whether these effects are generalizable across countries or different types of nature contact. Using representative cross-sectional samples from 18 countries/regions, we examined the associations between two types of nature contact (greenspace, nature visits), current smoking and everyday drinking. After controlling for a range of covariates, greenspace was inversely associated with current smoking and everyday drinking. Visiting natural spaces at least once a week was linked to a lower prevalence of current smoking, but unrelated to everyday drinking. Increasing residential greenspace could be a promising strategy for reducing multiple health risk behaviours, whilst visit-based interventions may be a more appropriate target for smoking cessation.

Planetary health agendas need a strong human rights focus. Both public health and the human right to a clean, healthy, and sustainable environment depend on biodiversity, ecosystems, and a healthy biosphere. Targeted transdisciplinary health research, action, and communication on biodiversity-health linkages can clarify and reinforce the human rights obligations of public authorities whose decisions might negatively affect the environment. However, our observations across law, policy, science, and advocacy show that there is a void of transdisciplinary guidance on how to apply the human right to a healthy environment to impact policy and law. We introduce a biodiversity-health roadmap to the UN Framework Principles on Human Rights and the Environment. This roadmap is only a starting point to co-develop and mobilise knowledge and policy-driven research and action agendas across the health-environment nexus, and among science, policy, and law professionals. In this Personal View, we invite knowledge co-development among health and environmental sciences, environmental law, human rights, and policy advisors to steer, mobilise, and focus the health-environment nexus on human rights to support more effective and coherent public decisions.

Although spending time in nature can improve subjective wellbeing (SWB), little is known about how different types of nature exposure are associated with different dimensions of SWB or the consistency of associations across national/cultural contexts. Using data from 18 countries, associations between green, coastal and freshwater blue space exposures (including residential availability, visits ‘yesterday’ and visits in the previous four weeks) and hedonic, eudaimonic, and evaluative wellbeing were estimated. Overall, residential nature availability showed little association with any wellbeing outcome, whereas visiting green and coastal locations ‘yesterday’ was associated with better hedonic wellbeing. Although frequently visiting green, coastal and freshwater spaces were all associated with greater evaluative wellbeing, greater eudaimonic wellbeing was only associated with frequent visits to green and freshwater spaces. Variations existed across countries. Results suggest that different types of nature exposure vary in their association with different dimensions of SWB. Understanding these differences may help us maximise the potential of natural environments as SWB-promoting resources.

Physical activity (PA) reduces the risk of several non-communicable diseases (NCDs). Natural environments support recreational PA. Using data including a representative cross-sectional survey of the English population, we estimated the annual value of nature-based PA conducted in England in 2019 in terms of avoided healthcare and societal costs of disease.Population-representative data from the Monitor of Engagement with the Natural Environment (MENE) survey (n = 47,580; representing 44,386,756) were used to estimate the weekly volume of nature-based recreational PA by adults in England in 2019. We used epidemiological dose–response data to calculate incident cases of six NCDs (ischaemic heart disease (IHD), ischaemic stroke (IS), type 2 diabetes (T2D), colon cancer (CC), breast cancer (BC) and major depressive disorder (MDD)) prevented through nature-based PA, and estimated associated savings using published costs of healthcare, informal care and productivity losses. We investigated additional savings resulting from hypothetical increases in: (a) visitor PA and (b) visitor numbers.In 2019, 22 million adults > 16 years of age in England visited natural environments at least weekly. At reported volumes of nature-based PA, we estimated that 550 cases of IHD, 168 cases of IS, 1,410 cases of T2D, 41 cases of CC, 37 cases of BC and 10,552 cases of MDD were prevented, creating annual savings of £108.7million (95 % uncertainty interval: £70.3million; £150.3million).Nature-based recreational PA in England results in reduced burden of disease and considerable annual savings through prevention of priority NCDs. Strategies that increase nature-based PA could lead to further reductions in the societal burden of NCDs.

Around the world, groundwater salinity levels are increasing in coastal areas, as a result of its systematic overexploitation for domestic, agricultural and industrial demand and potentially due to climate change manifestations (such as, sea level rise). We hypothesized that the groundwater quality of many Mediterranean coastal areas is already being perturbed, especially for water salinity, depending on the groundwater distance from the seafront. The objectives of this study were: i) to evaluate the magnitude and temporal variance of drinking water sodium (Na) as a metric of salt intake used for public health purposes using drinking water data in Cyprus; and ii) to examine the degree of Na enrichment in drinking water as defined by the seawater coastline distance of each sampling point. Open access governmental data of drinking water Na (n = 3304), daily max ambient air temperature and total rainfall were obtained for the period of 2009-2020 from governmental repositories. Linear mixed-effect regression models of drinking water Na with unsupervised covariance matrix were used. After adjusting for temperature and rainfall data, there was a significant annual increase in drinking water Na levels over time (beta = 0.01; 95 % CI: 0.00, 0.02; p = 0.02) for the coastal areas (<10 km from coastline, cutoff used by the EU Environment Agency), but this was not the case for non-coastal areas (>10 km distance from coastline). The distance of each sampling point from the coastline in Cyprus was negatively associated with drinking water Na in coastal areas (beta = -0.04, 95%CI: -0.06, -0.01; p = 0.002); this was not the case for non-coastal areas. More research is warranted to better understand the impacts of global environmental change on water quality in association with the burden of disease in coastal areas.

Population exposure to high temperatures poses health risks and increases mortality. 'Cool roofs' (high-albedo roofs) and rooftop photovoltaics (RPV) may reduce temperatures in urban areas. Here, using advanced urban climate modeling, we model impacts of these measures on air temperature and heat-related mortality in London during the record-breaking hot summer of 2018. We estimate changes in mean near-surface air temperature of -0.3 degrees C in the RPV scenario and -0.8 degrees C in the cool roof scenario. We find that the heat-related mortality in this period (estimated 655-920) could have been reduced by 96 (12%) by RPV, or 249 (32%) by cool roofs, in scenarios where all roofs have these measures. Monetized using value of statistical life, we estimate benefits for RPV and cool roofs of 237 pound M and 615 pound M, respectively. We estimate that up to 20 TWh of electrical energy would be generated in the full RPV scenario. We show that, for conditions such as in London June-August 2018, RPV or cool roofs may reduce near-surface air temperatures and associated heat-related mortality, with cool roofs having a larger effect.

Many countries have adopted targets to increase marine protected areas (MPAs) to limit the degradation of water bodies. Although there is evidence that MPAs can conserve marine life and promote biodiversity, there are limited data on the human health implications of MPAs. Using panel data from 1990, 2000, and 2014, we estimated the country-level associations between MPAs (i.e., percentage of territorial waters designated as marine reserves) and age-standardized mortality (i.e., age-standardized probability of dying between 15 and 60 years from all-causes among ages 15–60/100,000 population) by sex, among 110 countries. We fit mixed-effects linear regression models of mortality as a function of current MPA coverage, gross domestic product growth, year, the prior extent of MPA, electricity coverage, governance, and country-level random effects. We observed a significant inverse association between current MPA coverage and adult mortality. For each 5-percentage-point increase in current MPA coverage, a country had 0.982 times the geometric means of female and male mortality [geometric mean ratio: 0.982 (95% CI 0·976, 0·988)] conditional on past %MPA coverage and other modeled variables. The model showed no significant residual association of mortality with past %MPA conditional on current %MPA and other modeled variables. This is one of the first studies to show a positive association between increasing marine conservation and human health. This macro-level study suggests there may be important co-benefits for human health from expanding MPAs that merit further investigation.

Whilst green space has been linked to healthier sleep outcomes, the roles of specific types of nature exposure, potential underlying mechanisms, and between-country variations in nature-sleep associations have received little attention. Drawing on cross-sectional survey data from an 18-country sample of adults (N = 16,077) the current study examined: 1) the relative associations between six different types of nature exposure (streetscape greenery, blue view from home, green space within 1 km, coast within 1 km, green space visits, blue space visits) and insufficient sleep (<6 h vs. 7-10 h per day); 2) whether these relationships were mediated by better mental wellbeing and/or physical activity; and 3) the consistency of these pathways among the different countries. After controlling for covariates, neighbourhood nature measures (green space, coast within 1 km) were not significantly associated with insufficient sleep; but nature visible from home (streetscape greenery, blue views) and recreational visits to green and blue spaces were each associated with less insufficient sleep. Significant nature-sleep associations were mediated, to varying degrees, by better mental wellbeing, but not self-reported physical activity. Country-level heterogeneity in the strength of nature-sleep associations was observed. Increasing nature visible from the home may represent a promising strategy for promoting healthier sleep duration at the population level, whilst nature-based interventions encouraging individuals to spend time in local green/blue spaces may be an appropriate target to assist individuals affected by insufficient sleep.

Populations consuming saline drinking water are at greater risk of high blood pressure and potentially other adverse health outcomes. We modelled data and used available datasets to identify countries of higher vulnerability to future saltwater intrusion associated with climate change in 2050 under Representative Concentration Pathways (RCP)4.5 and RCP8.5. We developed three vulnerability criteria to capture geographies with: (1) any coastal areas with projected inland saltwater intrusion of ≥ 1 km inland, (2) > 50% of the population in coastal secondary administrative areas with reliance on groundwater for drinking water, and 3) high national average sodium urinary excretion (i.e., > 3 g/day). We identified 41 nations across all continents (except Antarctica) with ≥ 1 km of inland saltwater intrusion by 2050. Seven low- and middle-income countries of higher vulnerability were all concentrated in South/Southeast Asia. Based on these initial findings, future research should study geological nuances at the local level in higher-risk areas and co-produce with local communities contextually appropriate solutions to secure equitable access to clean drinking water.

A healthy ocean is essential for human health, and yet the links between the ocean and human health are often overlooked. By providing new medicines, technologies, energy, foods, recreation, and inspiration, the ocean has the potential to enhance human health and wellbeing. However, climate change, pollution, biodiversity loss, and inequity threaten both ocean and human health. Sustainable realisation of the ocean’s health benefits will require overcoming these challenges through equitable partnerships, enforcement of laws and treaties, robust monitoring, and use of metrics that assess both the ocean’s natural capital and human wellbeing. Achieving this will require an explicit focus on human rights, equity, sustainability, and social justice. In addition to highlighting the potential unique role of the healthcare sector, we offer science-based recommendations to protect both ocean health and human health, and we highlight the unique potential of the healthcare sector tolead this effort.

To focus on voters' priorities, Bill Clinton's campaign famously used the slogan, “It's the economy stupid.” With growing environmental crises, is this still true? We explored this issue for the marine sector, using representatively-weighted survey data from 14 European countries (N = 11,130). Citizens were asked about their own and policy makers' (perceived) preferences for marine-related economic, environmental, and human health policy goals. Results found the public consistently prioritised environmental protection and, to a lesser extent, health over economic growth. However, the public believed that policy makers cared less about the environment and health, but more about the economy than they did themselves. These patterns were consistent across all countries, all points of the political spectrum, and among coastal and inland residents. Marine policy makers who care about public opinion, may want to start considering that, at least for the European public, it is increasingly about “the environment, stupid!”.

Due to global climate change and anthropogenic activities, many low-lying coastal communities experience high sodium in drinking water as a result of saltwater intrusion, an emerging environmental health problem in many coastal regions. Drinking saline water is associated with higher sodium intake and hypertension. Exposure to higher ambient temperatures is common in many regions affected by saltwater intrusion, particularly in tropical and subtropical regions. Little attention has been given to the role of ambient temperature in the epidemiological association between drinking saline water and population blood pressure. We argue that high ambient temperatures increase water salinity and influence communities' sodium intake, urinary sodium excretion, and blood pressure. Hence, we hypothesize that ambient temperature is a potential confounder for the relationship between drinking saline water and population blood pressure. Testing the hypothesis requires a detailed measurement of urinary, blood, and sweat biomarkers (e.g., sodium), the population's blood pressure, and their drinking water’s salinity. An increasing number of coastal regions and islands will face the dual burden of high ambient heat exposure and saltwater intrusion in the future. Future studies are needed to determine the association between drinking saline water and blood pressure after adjusting for ambient temperature in saltwater intrusion-affected regions.

Introduction: Men are vulnerable to ambient heat -related kidney disease burden; however, limited evidence exists on how vulnerable women are when exposed to high ambient heat. We evaluated the sexspecific association between ambient temperature and urine electrolytes, and 24 -hour urine total protein, and volume. Methods: We pooled a longitudinal 5624 person -visits data of 1175 participants' concentration and 24hour excretion of urine electrolytes and other biomarkers (24 -hour urine total protein and volume) from southwest coastal Bangladesh (Khulna, Satkhira, and Mongla districts) during November 2016 to April 2017. We then spatiotemporally linked ambient temperature data from local weather stations to participants' health outcomes. For evaluating the relationships between average ambient temperature and urine electrolytes and other biomarkers, we plotted confounder -adjusted restricted cubic spline (RCS) plots using participant -level, household -level, and community -level random intercepts. We then used piecewise linear mixed -effects models for different ambient temperature segments determined by in flection points in RCS plots and reported the maximum likelihood estimates and cluster robust standard errors. By applying interaction terms for sex and ambient temperature, we determined the overall significance using the Wald test. Bonferroni correction was used for multiple comparisons. Results: The RCS plots demonstrated nonlinear associations between ambient heat and urine biomarkers for males and females. Piecewise linear mixed -effects models suggested that sex did not modify the relationship of ambient temperature with any of the urine parameters after Bonferroni correction ( P < 0.004). Conclusion: Our findings suggest that women are as susceptible to the effects of high ambient temperature exposure as men.

Disentangling the impact of the weather on transmission of infectious diseases is crucial for health protection, preparedness and prevention. Because weather factors are co-incidental and partly correlated, we have used geography to separate out the impact of individual weather parameters on other seasonal variables using campylobacteriosis as a case study. Campylobacter infections are found worldwide and are the most common bacterial food-borne disease in developed countries, where they exhibit consistent but country specific seasonality. We developed a novel conditional incidence method, based on classical stratification, exploiting the long term, high-resolution, linkage of approximately one-million campylobacteriosis cases over 20 years in England and Wales with local meteorological datasets from diagnostic laboratory locations. The predicted incidence of campylobacteriosis increased by 1 case per million people for every 5° (Celsius) increase in temperature within the range of 8°-15°. Limited association was observed outside that range. There were strong associations with day-length. Cases tended to increase with relative humidity in the region of 75-80%, while the associations with rainfall and wind-speed were weaker. The approach is able to examine multiple factors and model how complex trends arise, e.g. the consistent steep increase in campylobacteriosis in England and Wales in May-June and its spatial variability. This transparent and straightforward approach leads to accurate predictions without relying on regression models and/or postulating specific parameterisations. A key output of the analysis is a thoroughly phenomenological description of the incidence of the disease conditional on specific local weather factors. The study can be crucially important to infer the elusive mechanism of transmission of campylobacteriosis; for instance, by simulating the conditional incidence for a postulated mechanism and compare it with the phenomenological patterns as benchmark. The findings challenge the assumption, commonly made in statistical models, that the transformed mean rate of infection for diseases like campylobacteriosis is a mere additive and combination of the environmental variables.

High ambient heat can directly influence blood pressure (BP) through the vasodilation of the skin vasculature and indirectly by affecting urinary volume and electrolyte levels. We evaluated the direct and urine electrolyte-mediated effects of ambient temperature on BP. We pooled 5,624 person-visit data from a community-based stepped-wedge randomized control trial in southwest coastal Bangladesh from December 2016 to May 2017. Same-day ambient temperature data from local weather stations were linked to participant BP and urine electrolytes using geo-locations of their residential addresses. We implemented causal mediation analyses using the product methods of coefficients with linear mixed models under the sequential ignorability assumption. Separate models were run for each urinary electrolyte mediator (sodium, potassium, calcium, and magnesium), followed by combined models to evaluate the natural direct and electrolyte-mediated indirect effects of temperature on BP. Models had participant-level random intercepts and were adjusted for age, sex, body mass index (BMI), religion, exercise, smoking status, sleep hours, alcohol consumption, urine creatinine, time trend, household assets, drinking water salinity, and seasonality. For the combined mediators (sodium, potassium, calcium, and magnesium), for every 5°C increase in average daily temperature: the direct effect on systolic BP was -1.42 (95 % CI: -1.94, -0.92) mmHg and urine sodium mediated effect was -0.12 (95 % CI: -0.20, -0.05) mmHg; while urine potassium mediated effect was 0.15 (95 % CI: 0.08, 0.25) mmHg; urine calcium-mediated effect 0.06 (95 % CI: 0.01, 0.12) mmHg; and urine magnesium mediated effect -0.00 (95 % CI: -0.03, 0.02) mmHg. We detected similar associations for diastolic BP, pulse pressure, and mean arterial pressure. We found a significant inverse direct effect of ambient temperature on BP compared to minimally mediated urine electrolyte effects. Further studies are needed to uncover the underlying mechanisms of ambient heat and BP associations and to describe the clinical consequences of these associations.