I am pushing sixty. That is enough exercise for me. -- Mark Twain
Diet and exercise. The importance of both was known to the earliest humans, but today we know much more about how food and exercise affects our minds and bodies through scientific evidence. In this two-part series, I will explore the latest science behind diet and exercise and how they are ultimately the foundation of optimal health.
The view that exercise is medicinal is not a new one. In fact, healers have been recorded to "prescribe" exercise to patients dating back to antiquity. For instance, the Indian physician Susruta in 600 BCE indicated that exercise "should be taken every day" to half of total capacity, meaning nothing too rigorous or it may prove fatal. Ancient China had similar philosophies: The surgeon Hua T'o (100 AD) promoted exercises based on the movements of deers, tigers, bears, cranes and monkeys, which eventually became foundations of Shaolin Kung Fu. Like Susruta, he believed that excessive exercise was linked to disease states. From Hippocrates to today's physicians, exercise is now widely accepted as a therapy for preventing diseases like diabetes and for promoting overall health.
The effects of exercise on our body are pretty evident. Over the past dozen years, neuroscientists have been gathering evidence of exercise's benefits on brain function. To give you a little context, these are relatively new insights that stem from the paradigm shift in neuroscience that the brain is shaped by experience -- and is not a "fixed" structure with definite number of cells. Have you ever heard the myth, "You are born with all the neurons you will ever have"? Today, we know that not only does experience shape a brain, but that there are new brain cells being produced in specified areas all the time. And the best news is that exercising regularly can enhance the birth of new neurons and help them live longer. Some of these new cells are born in the brain area called the hippocampus, a region critical for learning and memory, which is sensitive to environmental factors like stress and exercise. Recently, scientists uncovered that breaking a sweat stimulates the production of the protein FNDC5 in the brain, an exercise-induced protein previously identified only in muscle. Over time, this protein stimulates our brain's BFF, another protein called Brain-Derived Neurotrophic Factor (BDNF), which nourishes new neurons and synapses, preserves the survival of existing brain cells, and is critical for learning and memory. BDNF also orchestrates the actions of other brain chemicals and systems, making it a crucial mediator for the ability of exercise to enhance learning and memory. So endurance training in particular can help trigger a biochemical cascade that in turn helps our brain create new neurons that survive, enhances brain plasticity and maintains our memory and cognitive skills.
It turns out your sweat sessions are doing more than just lower your stress levels -- it can actually mimic anti-depressants. A new study showed that exercising could purge the blood of a substance that accumulates during stress and disrupts neural plasticity, thus protecting the brain from stress-induced changes associated with depression. Depression is a common psychiatric disorder worldwide. The World Health Organization (WHO) estimates that more than 350 million people are affected. Understanding this disorder and developing therapies to alleviate symptoms is crucial to our global health. While research in this field is relatively new, other aspects of exercise, like its endorphin-boosting power, paint a clearer picture of how getting on your bike could have lasting effects on your mood and overall health.
Evidently, exercising keeps our brain in shape just as much as it does our bodies. The great news is that it doesn't take much to reap the benefits -- moderate exercise, brisk walks, even just 30 minutes a day -- can power up our brain to renew itself and keep us sharp as a tack.