Find your inner caveman

You have been walking all day, wading through the long grass that shimmers in the sun to crest a hill and drink in the view, before slipping into the coolness of dappled woodland

- Sam Pyrah

You picnicked by the river, where dragonflies darted and hovered. Now, as you make your way home, your fingers are red-stained and jammy-scented from the blackberries you picked. You feel tired, but happy: a rare sense of peace and contentment in body and mind.

It's no wonder that walking feels so uplifting and restorative: we evolved, quite literally, on two feet.

"Up until around 12,000 years ago - the blink of an evolutionary eye - everybody everywhere was a hunter-gatherer," says Professor Daniel Lieberman, chair of the department of human evolutionary biology at Harvard University. "Your ancestors survived by foraging for plants, hunting and fishing, regularly moving from one camp to the next."

Our bodies and brains were shaped by this lifestyle. We became efficient long-distance walkers and runners, which allowed us to range further and find a wider variety of foods.

"You had to be smart to track animals, find food, water and other resources," says Lieberman. "You had to remember where things were. You had to be able to communicate with language and to cooperate with others. All these demands selected for our cognitive abilities, helping us develop bigger brains."

MODERN MALAISE

But between 4,000 and 9,000 years ago, something changed. Europe transitioned into a continent of farmers (though a few hunter-gatherers, such as the Saami and Inuit, remained in marginal habitats). For the first time in the history of our species we stayed put, and we've been shaping our environment ever since.

In England, more than 80% of us now live in urban areas. We spend most of our time indoors (the average Brit spends less than 40 minutes a day outside) with and cooling; we travel by car or train or plane; we sit for hours on end, staring at screens.