In 1953, Professor Schumann of the University of Munich was teaching his students about the physics of electricity when they discovered the vibrational pulse of the planet Earth. The frequency is 7.83 Hz and is called the Schumann Resonance. It is caused by lightning striking between the earth and the ionosphere. All living creatures need this frequency to be healthy. In the city, it can be blocked by cell towers, microwaves, and pollution of all types including noise, radios, digital devices, computers, TVs, cell phones, air conditioners, lighting, telephone wires, power lines, appliances, etc. All create dissonant electromagnetic fields that are not natural to us or other species on Earth. We can't see them but may feel them in the form of stress, headaches, sleeplessness, and moodiness, among other more chronic and debilitating symptoms. Early Astronauts deteriorated away from the Schumann Resonance. Today a magnetic pulse generator sent into space with them solves this problem. So it is not just the fact that you love the fresh air and scenery, but when you are out in nature your body tunes into the earth's frequency and can repair, rejuvenate, and heal itself more efficiently.