Numerous studies show that living close to a natural environment, whether rural or coastal, is beneficial for human health. Among other things, it reduces overall mortality, cardiovascular diseases, depressive symptoms and increases the subjective sense of well-being. It is often suggested that the mechanism of this effect is psychological, as Jorge Wagensberg summarizes in that wonderful phrase: "the intense happiness we feel when seeing a free animal in nature, is nothing more than the nostalgia of when we lived in it".
The mere fact of looking at green spaces or walking through a park or forest, causes rapid psychological and physiological changes that can be demonstrated not only by psychological tests, but also by electroencephalograms, by means of cerebral blood flow measurements, by heart parameters of blood pressure and cortisol in saliva.
In the search to explain these changes, some authors have postulated a hypothesis from an evolutionary perspective. The natural environment could represent the equivalent of "habitat selection" of other species and therefore the relaxation and satisfaction we feel would be the natural response of any species to return to its natural habitat.
Thanks to studies of carbon isotopes in tooth enamel, we know that 3-4 million years ago, hominids evolved in wooded meadows and followed rivers and coasts or settled near lakes. Therefore, humans have evolved to obtain psychological rewards for approaching these ideal hunting-gathering habitats.
This reward is not only neuropsychological but is complemented by other factors that we usually find in natural environments: social interactions, exercise, and sunlight. It seems that the natural environment could promote social interactions and a sense of community in turn, green spaces are believed to encourage physical activity and of course exposure to sunlight. It is known that sunlight can counteract seasonal affective disorder (SAD) and has been used to treat tuberculosis and cure infected wounds.
We have seen that the benefits of coexisting with a natural environment really seem proven and can affirm that there are indications that suggest that living close to the natural environment has long-term health benefits.
Humans have an evolutionary predetermined need to expose ourselves to the natural environment, and when we do not, we feel nostalgic.