My expertise and academic background on this is zero.

But I'll add my own uninformed opinion just like everyone else.

I think it is because we live such an unhealthy indoor life.

Nobody goes out to play anymore. When I was a kid, there were other children swarming all over the streets. No longer. Instead, everyone is inside, glued to the tv or mobile apps.

Losing touch with the dirt, with the grass, playing, hiking - we lose touch with "mother earth." Maybe that means that as animals, we have been directly on the ground for all existence until now. It means that the negative ion charge from the ground was part of all of our existence. you get negative electrons when you put your bare foot or body on the ground.

Now, we are inundated with positive ions - cell phones, tvs, pollution, wifi. So our bodies collect positive ions and they stay in our bodies. Postive ions are removed when we step on the ground with our bare feet. Or during recess when we used to sit on the ground or fall on the ground doing various activities.

We also ground a gas tank to keep it from exploding...

Negative ions:

Reduce inflammation, which contributes to chronic disease
Improved sleep
Reduced cortisol levels
Relieve pain
Faster healing
Calms the sympathetic nervous system

The Earth’s surface is “the ‘battery’ for all planetary life.”

Shoes are insulators from the ground.

Feet are major portals to the natural world - our whole evolution we had mostly bare feet, or at least a lot of it.

Farming also connected us to the earth, even if wearing shoes, you get down into the dirt. Most of the population in even as soon as 120 years ago or so, 80 or 90% of people were involved in agriculture.

In addition to grounding, we also have removed much of sunshine, clean air and water, nutritious food, and physical activity.

Physical activity is also extraordinarily important. About 70% of the entire population in the USA is overweight or obese.

We have been growing slowly fatter but this has really escalated starting in the 1980s. I myself have noticed this. https://i1.wp.com/boingboing.net/wp-content/uploads/2012/03/...

This chart is so accurate and I personally noticed the EXACT same thing during this time period. Also, this graph is only for the obese and morbidly obese. Overweight is not included, but I'm sure that will be the same, if not more of a accelleration.

I grew up in the 1960s and 1970s and nobody was fat then. I remember the fattest person I ever saw, he was monsterous then. Now he would be on the slim side of fat.

We were not made to be this fat. It is so incredibly unhealthy on so many fronts, and there are SO many terrible side effects from being overweight or obese. It's not just one or two things. There are multitudes of being fat. It messes up all the hormones, creates all kinds of mental issues.

Shoot, I bet if we all got to our correct body fat percentages, the mental health epidemic would drop like a rock.

Put the phone down, get outside and walk for 2 hours per day. Exercise 2 hours a day.

And finally, food. Food is garbage today. Ice cream, cookies, candy, white flour, salt, white rice, potato chips, soda. You know what the unhealthy foods are. You should only shop on the "outside" aisle of the grocery store and not go up and down each aisle. Just the outside aisle - that is where they keep the veggies, fruits, dairy, meat - all the healthy stuff. The sole exception being if they have a bakery/donuts/etc on the outside wall.

I guarantee you that 2 hours outdoors, every day, will immediately dispell anxiety, depression, and the rest of the stuff by a great deal. Maybe not 100%, but maybe you will have only 10% of your stress and depression left in your body instead of 100%. Of course, not saying it will cure clinical depression, bipolar, schizophrenia, or any of that knind of mental illness.

Conceptually, it is the simplest, easiest fix in the world. But it is the most difficult to do. Because nobody wants to get out into the world and walk or hike. Nobody wants to put the donuts down.