THE POWER OF WOODLANDS, WALKING SLOWLY AND YOGURT

In the last couple of weeks I’ve done dozens of interviews on the subject of walking and landscape (I’ve got lots of guided walks and talks coming up for anyone interested in the transformative power of place – scroll to the end for more details). And the one question I often get asked is ‘How do I convince my partner that walking outside is better than the sofa/the gym?’This, of course, is the subject of The Walking Cure, published next week by Bloomsbury.  So I have plenty of answers.  Place, space and landscape affect us in potent ways – from nutrients and beneficial bacteria in the air, to sunlight, to the calming and restorative (or not) power of sound and scent.   Where we are is, up to a point, who we are: a fact highlighted by the Spanish supercentenarian, Maria Branyas, who – before dying in August last year at the age of 117 years and 168 days – attributed her long and healthy life to an “orderly life and pleasant surroundings.”

Maria was physically active to the end (a finale marred only by joint pain and hearing loss) and she loved walking. She lived in an area of Catalonia that included plenty of rolling hills and an abandoned railway line, now a green walkway, as well as beech and oak forests, and beautiful old buildings  (all landscapes which are now thought to have therapeutic qualities). So I was intrigued when a study arrived on my desk last week showing that people who regularly walk among trees have better immunity – merely because of their landscape-of-choice.  Maria never suffered from any cardiovascular issues, dementia, or tumours. So could her regular woodland walks have helped?

Quite possibly.

This study found that people who walked ‘leisurely’ (ie not briskly) for 45 minutes twice a day among trees dramatically improved their immunity, compared with walkers plodding the pavements of a more urban area. Researchers tested the salivary levels of walkers, before and after their ambles, finding that ‘forest walking considerably raises sIgA levels and enhances immune function.’ Their tests showed that forest walkers also had ‘significantly lower’ levels of the stress hormone, cortisol, as well as ‘significantly increased’ levels of dopamine, a neurotransmitter associated with happiness.

This reminded me of a study I came across a couple of years back which concluded that if everyone walked in woodland once or twice a week, the NHS (that’s the British National Health Service, for our overseas readers) could save £185 million from its annual mental health bill alone.

But what is salivary IgA and why does it matter?  SIgA is one of the five main types of antibodies produced by the immune system. It’s our SIgA levels that show how well our immunity is working. SIgA is associated with ‘neutralizing’ COVID, for example.  Interestingly, the researchers of this study think that the immunity of forest walkers improved because their stress levels fell, perhaps as a result of inhaling the terpenes pumped out by trees. Indeed, several studies have found forest amblers to have lowered levels of stress hormones, reduced blood pressure and improved heart rate variability.

As well as walking, Maria ate 3 yogurts every day containing Streptococcus thermophilus and Lactobacillus Bulgaricus, two strains available in most good yogurt brands.  The scientists that studied her (there’s a fascinating report on her supercentenarian biology here) were astonished by the high quality of her microbiome and have speculated that this – in combination with her fibre-rich Mediterranean diet – may have been the reason for her excellent health and longevity.

But walking outside would also have improved her microbiome, not only from breathing in the microbe-rich air but from touching trees or plant life as she strolled. When we touch the trunk of a tree or brush our hands against leaves we take in beneficial bacteria via our skin, adding to the diversity of our multiple microbiomes.

As Maria walked through woodland,  across the surrounding volcanoes and hills, and  along the dirt track of the disused railway line in her home town, she would also have engaged multiple muscles. Walking outside (unless you’re restricted to tarmac)  affects our gait, ensuring our feet, legs and vestibular/balance system also get a work-out.  Neither treadmill nor sofa can do this.

In fact mixing up our movement (as we do when we’re walking through multiple landscapes) appeared last week in a study which found better health and longer life among people using a variety of movements.  Outdoor landscapes often nudge us into more varied and challenging movement: walking on sand for example uses 2.7 more energy than walking on tarmac while simultaneously working the muscles of our toes.  You could also try interspersing your walk with some backwards steps, some skipping, some squats and lunges, some stretches. Or carry a backpack. Anything really. Or just welcome the varied terrain of outdoors, and embrace the mud/stones/sand/rutted tracks that naturally encourage our body to move slightly differently and to utilise different muscles.

Another benefit of being outside is the greater workout endured by our brain as we walk. A study last year compared outside walkers with indoor treadmill walkers, having put both groups into brain-scanning caps that monitored neural activity as they moved.  To the researchers’ surprise, the brains of outdoor walkers showed higher levels of restorative rest. Put simply, outdoor walkers became calmer and  more relaxed than indoor walkers.  Equally importantly, however, the outdoor walkers displayed greater connectivity in the brain.  The brain regions involved in reasoning, sensory perception and attention/focus began cross-firing. This didn’t happen to the gym walkers. Outdoor walking appears, therefore, to give our brain a little workout too.

And being outside also appeared, again, to be linked to good mental health … I’ve been banging on about this for ages.  But this study involving 13,000 adults found that the more time spent outdoors, the less depression and better sleep that participants had. What interested me in this study was the finding that the relationship between mood, sleep and being outdoors was more marked in older people.  As we get older, it appears that we need to be spending more time outside, not less.

Don’t forget to keep your head upright as you walk. Some of the benefit of walking outside appears to come from the volatile organic compounds and aeronutrients we inhale. But when our heads are down or thrust forward, we don’t breathe fully.  Joanna Hall, a sports scientist who coached me to walk in the best possible way, tells me that the diaphragm should have 10 cm of range, but with our head thrust forward, the diaphragm’s movement is reduced by 3-4 cm.  This means less oxygen and fewer nutrients. Lift your head!

On which note, I should get outside myself! It’s spring, and everything looks glorious so follow my lead, and head off for a walk. Just remember that every landscape has its own aerobiome and its own nutritional fingerprint – choose your destination accordingly.  Above all, walk in as varied locations as you can. Just like Maria.

My first event is in Sevenoaks, Kent on Tuesday 25^th March. We’ll be walking through the beautiful environs of Knole Park and I’ll be explaining how to optimise your walking and your walking locations. Tickets here https://sevenoaksbookshop.co.uk/walk-and-talk-with-annabel-streets/

I have more events coming up in Canterbury on 3^rd April, London on 2^nd May, the Chilterns on 17^th May and Yorkshire on 23^rd September. Details to follow but do put any convenient dates in your diary now.

Have a wonderful walking week!

Annabel