More nature equals less obesity and depression

Obesity or being overweight have been recognised as crucial health issues and have been included in the sustainable development goals. (Reuters)

Obesity or being overweight have been recognised as crucial health issues and have been included in the sustainable development goals. (Reuters)

Humanity now stands on top of nature, either smashing it or carefully curating it into designated spaces. Cement replaces green fields of grassland. With half the world’s population now living in cities, that means large parts of humanity no longer interact with green things.

That’s a problem for humans.
Nature is good for us. Concerned about the effects of humans living apart from nature, the Institute for European Environmental Policy collated all the research in that continent on what impact this separation has.

“The health and social benefits of nature and biodiversity protection” comes to the conclusion that people living near trees – and other green spaces – are less likely to be obese, inactive or chugging through each day on anti-depressants.

That research was done for the European Union bloc, and similar research has not been done for South Africa. But it focuses on dense cities, where poverty means it is the wealthy that have access to green spaces, such as parks. The enduring legacy of apartheid spatial development of local cities ensures that this remains an issue in South Africa.

The institute’s main findings are that people near green spaces are more likely to get into nature; to take walks or do more vigorous exercise. This comes with immediate benefits, but then also a whole host of benefits that are not immediately obvious.

  • Pregnant women living closer than 300m to a green space tend to have lower blood pressure than those living further away.
  • Children who grow up near green areas, where they get more exposure to plants and animals and bacteria, are much less likely to develop allergies.
  • People living more than 1km from a green space are more likely to be obese, and less likely to exercise vigorously than those living closer than that.
  • Middle-aged men in deprived urban areas that have green spaces have a 16% lower chance of dying (from any cause) than similar groups of men living in areas with little green space.
  • Doctors prescribe fewer antidepressants to people who live in urban areas that have more trees lining their streets.
  • People are generally happier and have lower mental distress when living in urban areas with more green spaces.
  • People living near green spaces are much more likely to engage in short-term exercise. This increases self-esteem, which is really beneficial to people who have mental health conditions.
  • Public green areas reduce urban temperatures, taking the sting out of midday heat. That means fewer deaths when temperatures reach dangerous levels, over 30°C. 
  • People recovering from stress-related mental health disorders and strokes spend 64% less time in hospital, if they spend their first year of rehabilitation in and around green spaces.

The most important long-term finding of the EU report is that green spaces are critical for people to live in cities as global temperatures increase. Data out in late March shows that globally, February was 1.1°C hotter than average.

Cities amplify this heat, with their cement buildings trapping and reflecting heat down streets. Pavements and tar roads then soak this up and give off heat throughout the day. For young and old people, that puts their bodies under intense heat stress, with people dying as a result. Some 20 000 people died in Europe in 2003 when a heat wave made temperatures in cities intolerable. Last year’s heatwave in India killed several hundred people.

For South Africa, the lack of green spaces is compounded by 3.3-million people living in corrugated structures. These cannot regulate heat. Small yards – or homes in apartment blocks – means there are not trees to escape the heat. Data from Statistics SA shows that formal parks are also more likely to be found in more affluent suburbs.

Research looking at the impact of the changing climate on human health in South Africa, published in the South African Medical Journal in 2014, warned that: “The health impacts are direct, such as increased temperatures leading to heat exhaustion, and indirect, such as likely increases in infectious diseases from contaminated water and changes in the distribution and magnitude of vector-born diseases (transmitted by a bite).”

But those dangers are being considered by government. Cognisant of the health benefits of green spaces, South Africa’s largest metros all have plans that reach towards 2050, outlining how trees and other ecosystems will be introduced to urban areas. That might go a small way towards ensuring the benefits of being in nature are shared more equally.

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