Take your brain for a walk (better still, a hike)
(This post supplements materials in chapters 3 and 10 of Connect with Nature). According to one of my early bushwalking mentors, ‘Americans hike, New Zealanders tramp, Britishers ramble, but Aussies bushwalk’. I was reminded of this when I read Dr Evelyn Lewin’s recent Sun-Herald magazine article (January 30,2022), ‘Take a hike’.
Evelyn, a general practitioner and health writer, draws a distinction between hiking and walking. Quoting Di Westerway, founder of Coast Trek , a hiking challenge for women, she says that there are two factors distinguishing a hike from a walk. ‘First you tend to push yourself more on a hike than a walk, Second, it [a hike] has to be out in nature’.
I say ‘potentially’, because a hike that excessively stresses us because we are not ready for it physically and/or mentally, can do more harm than good. That is why, where hiking and indeed all outdoor activities are concerned, I advocate the ‘gradualism’ principle – proceed from less to more demanding activities gradually.
But the activities you choose can be personally challenging, providing they are not distressingly so. Managing the challenges of hiking, such as fatigue, negotiating uneven surfaces, and managing ups-and-downs, can boost self-esteem, confidence and resilience.
Evolution has fashioned us to be very efficient hikers. Indeed, we humans are the creatures we are because we are hikers. Our walking style sets us apart from every other creature. Not even chimps, our closest hominid cousins, can stride, waddle-free, in the way we can. Nor can they match our (potential) ability to walk continuously for long distances (40km plus) – possibly because our walking action is so mechanically and physiologically efficient and because our body temperature is so effectively regulated by sweating (hence our almost hairless skin).
The endurance of our hunter-gatherer forebears enabled them to be ‘persistence hunters’, capable of sustaining a pursuit until their prey dropped from exhaustion or dehydration.
But the human talent for hiking did much more than make us athletic hunters. It also made us smart. Upright walking liberated our arms and hands for tool making and the development of fine motor skills, promoted multi-sensory co-ordination, and exposed our brains to ever expanding and changing environmental stimulation. In response, the human brain became a thinking, imagining and creative organ on top of being a reactive, learning and emotional one.
Together, walking and brain power secured humanity’s survival as a species; and the amazing alliance continues. Walking increases the brain’s readiness to cope with challenges to well-being and survival, while the brain directs and regulates walking to the same end. To walk, especially energetically and in nature, is to exercise our brain as well as our body.
The exertion involved in walking increases heart rate and the flow of blood to the brain as well as the body. Both body and brain are invigorated as a result. It is not surprising that many people say, as did the philosopher René Descartes, they think better when they are walking.
And they almost certainly do – for other reasons as well. Energetic walking or hiking also enhances brain activity by stimulating the production and deployment of neurotransmitters. These are chemicals that regulate the passage of signals from one nerve cell or neuron to another. Some of these neurotransmitters (glutamate and GABA, for example) operate throughout the brain and nervous system, but others have more specialised functions and localised regions of activity.
Some of these specialised neurotransmitters (endorphins and serotonin) clear the way for learning, thinking and other forms of cognitive activity by boosting mood and countering stress and anxiety. Others (dopamine and norepinephrine) increase emotional control, attention and concentration, while one (anandamide) has been linked to creative or lateral thinking. It is surprising how new and helpful perspectives on projects, issues and problems can pop into your head when you are walking comfortably and rhythmically though the bush, the rural countryside or along a beach.
Hiking is very much more than a matter of getting from A to B. It is more than a way of exercising our bodies and safeguarding our physical health. It is a stimulus to our intellects, to our minds, to our brains. Indeed, hiking can help our brains repair themselves and slow cognitive decline. The brain produces its own regenerative chemical (BDNF – brain derived neurotrophic factor) which facilitates the growth of neurons to replace ones that have died, including those in brain regions involved in memory. Vigorous exercise, including hiking, stimulates BDNF activity.
So, if you want to maintain your brain power, including your working and short-term memory, take your brain for a hike – and often.