Green Space and Human Health

Awareness is growing worldwide about the health impacts of green space. The World Health Organization recommends that all people reside within 300m of green space.

Park Prescriptions

A walk in the park a day keeps the doctor away. There is extensive research on the positive impacts of green space exposure on health and well-being. Increasing numbers of healthcare professionals are encouraging their patients to spend time in nature, otherwise known as ‘park prescriptions’.

The reduction of several chronic diseases and associated symptoms, including anxiety, obesity and cardiovascular disease, has been associated with the presence of and access to green space. Increased green space can also improve perceptions of neighborhood safety and lead to an actual reduction in crime rates as measured by police reports.

The Importance of Green space for Mental Health

As countries become increasingly urbanized, the world’s population is spending increasingly less time exposed to natural environments. It has been reported that 55% of the world’s population live in urban areas and this is expected to increase to 68% by 2050 (United Nations, 2018). Unfortunately, urbanization not only means spending less time in natural environments but more time destroying them and reducing the number of green spaces around the globe. Aside from the detrimental environmental effects of this, loss of these green spaces and time spent in them could have hugely negative effects on people’s mental health and well-being.

Green spaces can lower levels of stress and reduce rates of depression and anxiety, reduce cortisol levels and improve general well-being. Not only can a simple walk in nature boost your mood but also improve your cognitive function and memory. Green spaces can provide a buffer against the negative health impacts of stressful life events.

A Dutch study showed that residents with a higher area of green spaces within a 3km radius had a better relationship with stressful life events which was soon to be increasingly important in recent years with the effects of COVID-19. A recent study found that those who had access to natural spaces during the COVID-19 lockdowns had lower levels of stress and those that could view nature from home had reduced psychological distress.

Green spaces also promote certain behaviours, such as encouraging physical activity within the space, which is a pro-mental health behaviour.

Particularly children, appear to benefit from green space. For example, one study showed that children who went to a school with more green space had considerably better cognitive functioning than those who went to a school with less green space, while another study found that early childhood exposure to green space leads to fewer mental health problems in adult life.

Climate Change

Climate change is causing more severe and frequent heatwaves, drought, rainfall and storms. Increasing the number of green spaces can help to combat the effects of climate change. This is achieved by providing natural cooling of air and surfaces, supporting water management in urban areas and capturing carbon dioxide from the atmosphere.

Vegetation included in urban design has the added benefit of absorbing and storing carbon dioxide, helping to limit the rate of climate change. A mature tree can absorb up to 150 kg of carbon dioxide every year – planting 12 trees can offset one year’s worth of a person’s entire carbon dioxide emissions.

Green Spaces and Longevity

Green spaces in cities can help people live longer. Recent estimates put around 3.3% of global deaths down to a lack of physical activity, mostly as a result of poor walkability and limited access to recreational areas.

Green space in cities reduces premature mortality. It was found that for every 0.1 increment in vegetative score within 500 meters of a person’s home, there was a 4% reduction in premature mortality.

Immunity

Higher ratio of green spaces was associated with reduced disparity in coronavirus infection rates. More access to green spaces is likely to promote physical activity, which may enhance the immune system. Green spaces enhance mental health and reduce stress, which also promotes immune system health. They strengthen social ties, which is an important predictor of health and well-being, the researchers said. Green spaces also may decrease infection risk by improving air quality and decreasing exposure to air pollutants in dense urban areas.

Contact with green space has been found to be ‘restorative’, both psychologically and physiologically, reducing blood pressure and stress levels and potentially promoting faster healing from surgery.

Green Spaces are Beneficial for Children’s Lung Health

Children who have access to green spaces close to their homes have fewer respiratory problems, such as asthma and wheezing, in adulthood and tend to have better lung function. Getting closer to nature reduces stress, which can improve physical health and might have a positive effect on children’s microbiomes – the community of different bacteria that live in our bodies.

Living in greener neighborhoods as children grow up is more important for their breathing than living in a green area when they were born. This may be because babies spend much less time outdoors than children. Moving to greener areas may be a possible strategy to improve children’s lung function. Trees were associated with greater reductions in hospitalization when pollutant levels were higher.

Benefits of Green Spaces on Birth Outcomes

An increasing number of studies have reported associations between maternal exposure to green spaces and higher birth weight. There is scientific evidence that maternal exposure to natural environments supports healthy fetal growth.

A healthy fetal growth can greatly reduce the risk of adverse health outcomes, both early and later in life. For example, babies with low birth weight could have an increased risk of growth impairment, lower IQ and premature death in childhood, as well as obesity, cardiovascular disease and diabetes in adulthood.

Green Space and Preterm Birth

Maternal exposure to residential green space was associated with decreased risk of preterm birth (born < 37 completed gestational weeks), especially in the second trimester. There is a synergistic effect between low green space and high air pollution levels on preterm birth, indicating that increasing exposure to green space may be more beneficial for women with higher air pollution exposures during pregnancy.

Virtual Green Space Boosts Pregnant Women's Well-being

Visual exposure to a virtual green space environment was associated with lower systolic blood pressure, reduced salivary alpha-amylase (an indicator of stress), improved positive emotions, improvements in mental health and well-being and decreased negative emotions compared to the non-green space environment. Exposure to a high green space environment in a park-like setting had the strongest impacts on stress recovery.

Green Space and Cardiovascular Disease

Exposure to green space has been proposed to be beneficially associated with cardiovascular morbidity and mortality. Mortality rates for ischemic heart and cerebrovascular diseases are inversely associated with exposure to green spaces. Trees reduce risk of cardiovascular disease by promoting physical activity, reducing stress, mitigating excess heat and air pollution. High quality green spaces can also reduce loneliness, which then also benefits heart health.