In the last issue of Optimyz, I talked about the runner’s high and made reference to neurogenesis after exercising and promised I would post my very first science column article for Optimyz where I discuss neurogenesis and wellness. This article was before Optimyz expanded across Canada so many of our readers would not have seen it – except for my mom in Winnipeg who is a subscriber! It’s less bloggy but still informative and, hopefully, interesting! Enjoy!
Why do we feel so good after exercising? You’ve probably heard of, or maybe experienced, a runner’s high, which happens when the brain’s natural “feel good” chemicals (endorphins) are active. In fact, exercising has many benefits like enhanced learning, memory, and anti-depressant effects. These cognitive and emotional benefits of exercise seem to be a result of an increase in cell growth in the brain.
Briefly, exercise enhances cognition in children, young adults, and ageing adult. For example, exercise improves children’s intelligence scores, learning performance, measures of reasoning, vocabulary, memory, reading skills, and reduces inattentiveness, etc. Similar results were found in young adults. In ageing adults, exercise improves working memory, reasoning, vocabulary, and reaction time. One study also found better brain functioning and greater brain volume in aged adults who were exercising compared to their sedentary counterparts.
Much of the benefits of exercise, both cognitive and emotional, appear to happen through changes in a particular area of the brain called the hippocampus. The hippocampus is most known for its role in learning and memory. We first came to know of this phenomenon over 50 years ago when a patient with epilepsy was surgically removed of his entire hippocampus to try to stop the seizures. Following the surgery, the patient formed virtually no new memories proving the hippocampus to be important in memory.
About 15 years ago, this area of the brain became very popular because researchers started to accept evidence for cell growth in the adult brain, called neurogenesis – ending a scientific dogma that adult brain cells could not regenerate.
The ability of the brain to “regrow” has vast implications for brain repair following disease or damage and brain enhancement, all of which could affect many valued human traits like learning, memory, and emotional wellness. We now know a lot about neurogenesis including that it does enhance learning and memory and that when neurogenesis is prevented in the hippocampus learning and memory is impaired. Interestingly, the strongest promoter of neurogenesis is exercise!
The hippocampus is one of a few areas of the brain where neurogenesis occurs. The hippocampus also houses lots of different receptors that are used by many natural chemicals (neurotransmitters) in the brain. For example, it houses corticosteroid receptors – receptors that respond to stress hormones. Too much stress actually destroys part of the hippocampus, which helps explain why our memory is worse after periods of severe stress.
The hippocampus also houses serotonin receptors – receptors that respond to the brain’s natural anti-depressant neurotransmitter ‘serotonin’. Conventional medicine uses of SSRIs, Selective Serotonin Reuptake Inhibitors, to keep serotonin floating around making it more likely to hit its receptors. An excess of serotonin enhances neurogenesis, which creates a sense of emotional wellness.
Exercise also enhances neurogenesis, which, not surprisingly, also creates a sense of emotional wellness. In fact, exercise has also proven to be as effective as common anti-depressants (i.e., SSRIs like fluoxetine) in reducing the symptoms of depression, which explains why many doctors are prescribing a healthy dose of regular exercise!
If exercise hasn’t already proven to be a wonder drug in your mind, chew on this: Exercise protects the brain against stroke, promotes recovery following brain damage, reduces the cognitive decline in Alzheimer’s disease, and has numerous other general health benefits that you are already well aware of. This list is long and growing.
So… Enjoy your workout… and your neurogenesis!