The sea squirt starts life as a free swimming animal with a tail, an eye, a spine and a primitive brain. However, after a time it attaches itself permanently to a rock and undergoes ‘retrogressive metamorphosis’ losing its eye, spine and brain to become a water-pumping filter-feeding ‘blob’. Free movement requires brain power, static existence does not!
Three fascinating ideas emerge from modern study of the human brain. Firstly the adult human brain is capable of generating new neurons to repair and improve its function. Until recently it was believed that this facility was lost along with the transition to adulthood.
The second is that movement and exercise play a crucial part in this regeneration. It is now ‘old hat’ that exercise is good for the health of the body – and it is also now very clear that mental well-being also benefits. However, this science is suggesting something more – that the physical brain can be improved, grown you might say, by exercise.
The third, and possibly most revolutionary, is this ‘exercise’ does not require a visit to the gym, sweat or anaerobic exertion! The calculations required to control the locomotion, navigation and balance of an upright biped as it traverses complex terrain require major brainpower. We have been taught to think of these functions as automatic or ‘hard wired’ and therefore trivial. This is wrong – walking is a complex brain workout. If that walking also involves uneven surfaces, multiple sensory inputs from a potentially hostile environment and the need to navigate (create a mental model of the terrain around us) – the mental exercise is supercharged.
This all makes sense if we think of our hunter-gatherer ancestors traversing great distances through complex wooded terrain, finding their way, avoiding predators, seeking prey. Always looking in three dimensions, listening, feeling the ground beneath their feet, tasting and smelling the air. If we restrict our walking to waymarked, asphalt-smooth and regularly stepped, risk-assessed, pre-packaged ‘trails’, I suggest much of this benefit may be lost.
We need to walk wild to reconnect our brains to our senses and escape the fate of the sea squirt!
Sources / Reading
- ‘It’s a superpower’: how walking makes us healthier, happier and brainier’
Amy Fleming in the Guardian interview/walk with Neuroscientist Shane O’Mara
- The evolutionary history of humans explains why physical activity is important for brain health
David A. Raichlen and Gene E. Alexander in Scientific American
- Meet the creature that eats its own brain!
Steven Goodheart on his blog Goodheart’s Extreme Science