We are all familiar with the health problems caused by obesity. These problems are peculiar to a modern sedentary way of life and are virtually unknown in physically active subsistence societies. Now evidence builds that physical activity is crucial for brain health, and even for creativity.
Central nervous systems were designed by natural selection primarily to control movement, although they also regulate many aspects of physiology from sleep and energy balance, to breathing, hormones, ion concentrations in the blood, and scores of other controlled systems.
That physical activity stimulates the brain is therefore no surprise. If the body is active, the brain is forced to be active also. This point is illustrated by sleep deprivation where the best way of staving off drowsiness is to do pushups, or some other type of exercise.
The healthy mind in a healthy body notion was advocated by the ancient Romans, thus linking a healthy brain to an active body. This is a two-way street. It turns out that highly educated individuals live longer than their less-educated counterparts (1). This phenomenon is most likely explained by the fact that people with more active brains have better circulation of blood in their brains so that they are less vulnerable to senile dementia. Of course, physical activity provides similar benefits for brain function, implying that the brain, considered as a movement control system, does not distinguish between cognitive work that is done while sitting at a desk studying and processing information whilst moving through space.
This point is confirmed by a study of London cab drivers who had to learn how to navigate all the city streets without maps or GPS and who were formally tested on “the knowledge.” Their navigational feats produced enlargement in an area of the hippocampus associated with spatial memory (2). The longer they drove a cab for, the greater the effect, so that this was not just a matter of people with exceptional spatial ability getting selected into the occupation.
This study and others dealing with specialized skills, such as learning to play an instrument, show that the mature brain is highly malleable, or “plastic” but they do not link gross motor activity with brain function. Fellow blogger, Damon Young, described many intriguing links between highly creative individuals and the habit of daily walking.
Charles Darwin and poet William Wordsworth were inveterate hikers and Young describes how they and others worked out their creative kinks in peripatetic style. (I once estimated that Wordsworth put up as many miles from his daily ramble of some 10 miles as a good Japanese car).
Darwin solved problems deliberately by going for a walk and calibrated the difficulty of a problem by how long a walk it took to solve it.
This seems unusual. Most creative walkers do not bring their problems with them. Instead, they take a holiday from mental effort and hope to return refreshed and invigorated, ready to address the crux with now energy and more varied tactics.
Canadian neuroscientists produced some startling evidence in support of this tactic (3). They concluded that voluntary exercise greatly increases the proliferation of stem cells in the dentate gyrus of the hippocampus, so that a keen hiker benefits from having more cells.
The hippocampus plays a key role in forming new memories and is also implicated in spatial problem-solving as illustrated by the cabbies study. No wonder that physical activity, even of a pedestrian nature, might boost creative problem-solving.
The same researchers concluded that environmental enrichment helps more of these new cells to stay alive, suggesting that the route traversed should be varied as much as possible for maximum effect.
The general health benefits of walking are well known in relation to fitness, cardiovascular health, and general immune function. Of course, hiking is also useful for combating stress and depression. Moreover, anyone who gets from A to B via Shank's mare cannot possibly be in a hurry. By default, they are members of the leisure class. As Aristotle pointed out, there is little benefit in being able to think if one does not have the time to reflect on the mysteries of life.
We do not all have the country homes that we deserve and therefore rely on enlightened urban planning to give us decent places to promenade. Those parks and trails are no longer just infrastructure for health and happiness: they are also infrastructure for intellect and creativity.
