Many of us know spending time outdoors in nature is good for your mental health, but how can it also benefit your physical health as well?

British fitness coach Joe Wicks has teamed up with neuroscientist Katherine Templar Lewis to scientifically test the widely-held belief that spending time outdoors is good for us, as part of a new podcast series called Health or Hype, from healthcare provider Bupa.

During the episode, he travels from London to spend a day in rural Cornwall and also tests the impact of nature closer to home by birdwatching on the Walthamstow Wetlands.

Throughout both experiences, he allowed researchers to examine his health data, including heart rate variability, EEG brain activity and self‑reported mood.

Wicks said he was interested to see “what’s really going on in the brain” when someone is in a more calming environment, in an interview.

“We went to this wonderful temperate rainforest in Cornwall, called Cabilla, and I basically immersed myself, with no phone or technology,” Wicks told me.

“The impact on me was amazing. I felt so calm and relaxed. It changed my mental health for sure.”

Templar Lewis said the preliminary results from Joe’s birdwatching experience showed a clear reduction in stress-related brain activity when Wicks spent time in nature, compared to when measured in much busier urban parts of London.

She added they monitored frontal alpha asymmetry, which measures the electrical activity between the left and right frontal regions of the brain.

Templar Lewis said they also monitored the frontal midline theta in Wick’s brain, which is related to attention and mental workload.

“When you are relaxed and engaged in nature, you have less to process, it gives the brain an opportunity to recharge, and refocus said Templar Lewis. It’s also been associated with a drop in cortisol, the stress hormone.

“With Joe, we saw within a short amount of time with him being in nature and bird watching, his heart rate slowed down, there was an increase in left frontal alpha, and his frontal midline theta started to drop supporting all the recent research into the power of nature to help us relax and restore.

Wicks said he was glad he took part in the experiment.

“You don’t need to spend days and hours in a rainforest. You can just be in an environment like a park for 20 minutes,” said Wicks.

“You could be walking along the river and taking a moment to be present with nature, and I want to do that for myself, but also want to teach that to my children. I want to instil in them that it’s okay to just sit and look up at the trees.”

Templar Lewis added there are other health benefits associated with being in nature, including cleaner air.

“We spend about 90% of our days indoors, and our brains have not evolved for that. When you are in nature, it can have this wonderful impact of relaxing the mind.

“When we look across natural patterns like clouds and leaves, we see our attention soften, its been linked to a creative alpha wave increase in our brain as we relax. We feel safe, when we’re in urban environments.

“And it does not have to be about visiting a forest - walking down a tree-lined street, or even bringing plants indoors, can give you a boost."

Dr. Melvin Samsom, group chief medical and sustainability officer at Bupa, said healthy people need healthy places, and the relationship between the two is closer than many of us realise, in a statement.

Dr. Samson added he hoped the podcast episode would hope to help people make informed decisions about their health while inspiring conversations about how the places we live, work and spend time in can influence our wellbeing.

The podcast series comes as a report by the Wildlife Trusts warns nearly half of all parliamentary constituencies in England have limited access to nature.

The chief executive of the Arbor Day Foundation, Dan Lambe said there is a growing amount of scientific evidence which shows how beneficial being around trees is to both our physical and mental health, in an interview.

He added there is also the Green Heart Louisville project in Kentucky, which is studying how planting thousands of trees in urban neighbourhoods can improve human health and lower chronic disease.

“We’re seeing more and more health institutions are embracing trees and green spaces, as a way to accelerate healing,” Lambe told me. “Everyone just realizes you feel better when you are near trees.”

Longevity and wellness expert Gary Brecka said even brief exposure to green space, in the is enough to bring cortisol down, in a statement.

Brecka added eight to 12 minutes of morning light in your eyes will do more to reset your circadian clock than almost anything else.

“It doesn’t take a remote safari. A park, a garden, a tree-lined street on the way to work all count,” he said.