A PhD in engineering that loves to train his body. He teaches math and in math, theories are disapproved with counterexamples. So I think it’s safe to say that he is the counterexample to the myth that an exercised body means less intelligence!
Memory loss, Stress and Rodent
We often think that working out is wearing and leads to just a great body without any gain regarding the brain. This conception is proven to be wrong in several studies on rodents. What happens is that when working out the brain reorganizing it in manner of its response to stress diminish and anxiety too. Joining this is the development of brain cells (i.e. the growth of brain cells aka neurogenesis) in the hippocampus (the part of the brain that is responsible for the long-term memory). So as we normally hear, the stress is linked with our memory. 
Memory loss sparked by stress has been deeply studied and if you bear to read more about it you can look at references. 
Also important is to take account of the long-term effects it holds in the brain. It’s believed that working out strengths the mechanisms that prevent brain cells who response to stress and anxiety (I remember reading about this, its called Hebbian Theory, you might like to read it as well the main idea is “cells that fire together, wire together”). 
The importance of reflecting
If we think about, most of our decisions made under stress underlay instincts for survival. With the sparkle of our instinctive actions it difficult us to ponder in order for taking the best actions. This sometimes can even make us regretting our lives for not being able to prevent something.
Imagine a situation where someone you love is going to be physically attacked by somebody and you can prevent it if you punch that somebody that is going to attack your beloved. However you stay petrified because you have never been in this circumstance (or you are not used to violent behaviour) and so you see he/she being brutally assaulted. It will make you feel very ashamed and agonized.
Now you can understand the importance of being able to have a relaxed reaction to a stressful event.
A recent experiment done in humans aimed to understand how the exercise effected the brain. Although it is a rough experience it predicts that, as we’ve seen in rodents, humans can also boost their memory through working out.
In this experiment two groups were formed and both sat viewing 90 photos. After this, one group worked out lifting weights (extending and contracting each leg at their personal maximum effort 50 times) while the others just stayed on the weightlifting machine and allowed the machine and the experimenter to move their legs. To conclude they were brought all together and had to view the same photos again mixed with another 90. The objective was to see how right each group recalled the first photos (that were now mixed).
The results for the group that didn’t work out were of 50% and the group that did work out were 60%. 
So we can inference that, even though the experiment is very basic, it shows that resilient workout can possibly boost the memory. Hence boosting our results in stressful moments (because with work out we recall more and our brain doesn’t react so much to stressing stimulus).
As always I hope you got the motivation to go to the gym and that you have learnt something new. Last note, don’t forget…Mind the body! 😀
If you liked this, you may as well like knowing how your body expression affect the brain (Amy Cuddy – “Your body language shapes who you are”)
References and further reading.
 – Hebbian Theory – Wiki