Tuesday, November 17, 2020

Secret Science Club Zoom Recap: Exercise Your Noggin!

 Tonight, the Secret Science Club is sponsoring a Zoom lecture with neuroscientist Dr Wendy Suzuki of NYU's Center for Neural Science.  This lecture is the Secret Science Club's annual Dana Foundation Brain Center lecture.  The topic of the lecture concerns the astonishing effects of exercise on the brain, and I will attempt to summarize the lecture as it proceeds.  Dr Suzuki's book Healthy Brain, Happy Life was adapted into a PBS program.

Dr Suzuki began the lecture by telling us that there was something we could be doing to change our brains, and to increase our brain health by exercising.  Physical activity has immediate, longterm, and protective effects on our brains.  She began to conduct an experiment on herself by harnessing the transformative effects of exercise.

Dr Suzuki's main area of interest is brain plasticity, the ability of the brain to change the brain. Dr Suzuki, as a freshman at Berkeley, studied under Dr Marian C. Diamond, the first neuroscientist to study the effects of environment on the adult brain.  Dr Diamond took two groups of rats, one of which was placed in a 'Disneyland for rats', full of toys and other rats, while another group was sent to an impoverished environment, with food and water, but few other rats and little variety.  As a neuroanatomist, she observed that the cerebral cortices of the rats in the rich environment had thicker outer layers.  Dr Suzuki was inspired to study the role of plasticity in the formation and retention of memories.  

The formation of long-term memories is dependent on the hippocampus.  Dr Suzuki wondered how a momentary experience. such as a first kiss, could form a lasting memory.  She studied the neurons' action potentials in the hippocampus as memories were formed.  She noted that she could have continued on in this field for years, but was inspired to change her topic of study when she gained twenty-five pounds when she was seeking tenure at NYU, grinding academically and subsisting on takeout.  On a river rafting vacation, she was dismayed to find that she was the weakest member of the expedition, and determined to get in shape.

Once she started exercising, she had more energy and better focus, and found a workout class mixing kickboxing, aerobic dance, and spoken affirmations.  She rebalanced her diet, lost the weight, and. while writing a multimillion dollar grant proposal, realized that her writing had improved due to improvements in focus and memory.  The grant proposal was dependent on her ability to memorize details from various papers.  She then decided to examine the literature concerning the effects of exercise on the brain, and saw that Marian C. Diamond's measurement of the cortices of blood, neurotransmitters, and brain angiogenesis, the growth of new blood vessels  was  increased by environmental enrichment, which also increased hippocampus neurogenesis.   What factor is critical for these changes?  The exercise wheel was a major factor in these changes.  As Dr Suzuki was examining the positive effects of exercise on her brain, she received a call from her mother, who told her that her father had gotten lost on his drive home from a favorite coffee shop.  While her focus, attention, memory, and mood were improving, her father was on a downward trajectory.  She studied the effects of exercise on the brain, even having her students exercise in class.  Even high-functioning students in a prestigious college could improve their performance with exercise.

How does exercise improve brain function?  Dr Suzuki displayed a photo of a brain she keeps (Betty, the most photographed brain in Manhattan), and displayed the hippocampus and the profrontal cortex, both of which benefit from exercise, both of which are vulnerable to aging and neurodegenerative disease.  

Acute exercise immediately changes the neurotransmitters coursing through the brain- dopamine, neuroepinephrine, and serotonin levels increase. Neurotrophins, such as BDNF, which repair and maintain the brain, increase.  Dr Suzuki jokingly described exercise as a 'bubble bath for the brain'.  Exercise improves mood, focus/attention, and reaction times immediately.  The long-term effects of exercises that improve cardiovascular fitness are evident in the prefrontal cortex and hippocampus by increasing neural growth factors.  Dr Suzuki quipped that she wants brand new shiny neurons in her hippocampus because they function better than her old ones.  Regular workouts help to grow new hippocampal cells- for a strong hippocampus, get a strong body.  Glial cells, support cells in the prefrontal cortex, also increase, and synapses improve.  There are functional changes in the prefrontal cortex due to exercise.

How much exercise is needed to create improvements?  In an experiment in conjunction with the exercise-cycle gym Swerve, these improvements were measured in low-fit subjects exercising three times a week.  The Swerve model actually measures caloric outputs for teams, using team competition as a motivating factor.  A control group played group video Scrabble.  Predictably, the spin classes raised heart rates more than video Scabble.  In the spin class group,mood was improved as was motivation to exercise more.  Attention and reaction times improved.  Hippocampus-dependent recognition ability improved in the spin class group.  Spatial memory improved with exercise. 

Physical exercise also has protective functions, the prefrontal cortex and hippocampus are vulnerable to neurodegenerative effects of aging.  Exercise shores up these areas of the brain, and larger cortices and hippocampi take longer to degenerate.  A study of middle aged women in Sweden over 44 years showed that highly fit women experience dementia an average of nine years after their low fitness counterparts.

What is the most effective form of exercise that will maximize your brain functions?  Dr Suzuki formed a company called BrainBody to provide a two minute brain evaluation before and after workouts.  Asked to give an thirty minute lecture to incoming NYU freshmen, she delivered a ten minute lecture followed by anxiety tests followed by ten minutes of exercise and a second anxiety test, which reduced anxiety by fifteen points.  She then led us in a three minute exercise session to end the lecture.

The lecture was followed by a Q&A session.  One question involved the role of exercise in improving cognitive biases, but there are no real studies.  A question about the benefits of martial arts elicited the response that these activities involve aerobic activity, resistance, and mediation so they are beneficial- she will be starting a ChiGong study soon.  Are there gender differences in the benefits of exercise?  Studies suggest women may see more improvement.  As far as time of day goes, Dr Suzuki indicated that exercise is best done before one needs cognitive productivity, but there are no systematic studies.  People have different circadian rhythms, though.  Regarding the effects of marginal increases, there is no study to show what an optimum rate of exercise is.  Anecdotally, her BrainBody work has shown that subjects who state that they are working out to their limit need more recovery time to show improved cognitive function.  A good, sweaty workout keeps the good doctor functionally well all day.  Regarding ADHD, there are a handful of studies being conducted- self experimentation, working out and documenting the effects, can help individuals track the improvements they see.  Some Bastard in the audience asked if there were studies concerning the relative benefits between working out in complex environments (e.g. biking on a bike trail) versus working out in an enclosed environment (e.g. stationary bike in a gym)- there are no studies, it's hard enough to get subjects to work out in a gym, much less outside.  For her, a living room workout suffices.  Regarding the pathways involved in the exercise/brain connection, muscles release a protein which passes the brain/blood barrier and increase production of BDNF, the liver also releases a ketone which stimulates growth factors.  There might be stimulants which could mimic this, but exercise is known to be beneficial.  Regarding cortisol stimulation induced by exercise, exercise is a stressor, but the cortisol improved doesn't seem to have deleterious effects.  Another question concerned the effects of the microbiome on brain health, and Dr Suzuki noted that diet as well as exercise played a critical role in brain health.  Another question regarded the brain's motivation to exercise... why is sitting on the couch so addictive?  The brain does indicate that junk food and vegging out are bad, but it takes conscious motivation to exercise.  Is a certain intensity of exercise necessary?  Not everyone has to be a triathlete- a second lap around the supermarket could suffice.  If you are just starting out, you have to do the least amount of exercise to see improvements- get the heart rate up with a power walk.  Find a workout that makes you feel like you worked, though.  Asked how to get involved with one of her studies, Dr Suzuki told the questioner that her subjects are NYU students, and most of her studies involve the effects of exercise on anxiety.  A high school student referred to the lecture asked about the evolutionary history of our need for exercise, and if our sedentary lifestyle is a 'self-induced disability'.  Dr Suzuki noted that we evolved to move, and modern individuals need to move more- she uses a standing desk, but she still can't be moving around a lot while writing.  BDNF and neurotransmitter levels in human subjects are studied through blood tests.

For a taste of that Secret Science Club experience, here is a video of Dr Suzuki lecturing on this subject:

Now, get up, shake your booty, and bask in that SCIENCE!!!  Kudos to Dr Suzuki, Dorian and Margaret, and the good people of the Dana Foundation.

1 comment:

Mike said...

The APDA (Parkinson's) pushes exercise exercise exercise to slow down the brain deterioration caused by the disease. 30 minutes a day gives the most benefit (85%), with more time have less benefit.