The below four articles are about the benefits of exercise on memory. If anyone knows of any additional information, studies, or references, about exercise, sleep, suppliments, diet, etc, please post time here.
1. Brain glycogen decreases during prolonged exercise.
https://www.ncbi.nlm.nih.gov/pubmed/21521757
The main takeaway here, I think, is that brain glycogen (stored complex carbohydrate that is quickly broken down into glucose for use as energy) is depleted considerably after 120 minutes of exercise but remains unchanged after 60 minutes of exercise; therefore, it looks like the window of efficacy for brain-energic adaptations occurs somewhere between 60-120 minutes of endurance exercise. In order to deplete brain glycogen, you really have to wear yourself out, so to speak. Muscle fatigue indicates brain fatigue.
2. Brain glycogen supercompensation.
https://www.ncbi.nlm.nih.gov/pubmed/22063629.1
This study picks up where the last one leaves off. Exhaustive exercise results in supercompensation of brain glycogen--your brain adapts and stores more energy, presumably to stave off fatigue the next time. And while, after just 24 hours, the beneficial adaptive effects diminish in subjects that do not continue an exercise regimen, after four weeks of daily exercise, 60 minutes a day, baseline glycogen is increased. The study also reports that all areas of the brain are affected, including the cortex and hippocampus, both strongly connected with memory.
3. Differential cognitive effects of cycling versus stretching/coordination training in middle-aged adults.
https://www.ncbi.nlm.nih.gov/pubmed/21895371
From what I can tell, adults' cognitive functions benefit similarly from endurance exercise as from stretching and coordination training. Based on the excerpt, I liken "stretching/coordination training" to yoga. Particularly, the yoga-esque training is good for episodic memory, which corresponds to time and place, as compared with procedural memory (muscle memory, repetition memory) or semantic memory (higher memory associated with cognitive reasoning, etc).
4. Daily running promotes spatial learning and memory in rats.
https://jssm.org/vol6/n4/7/v6n4-7pdf.pdf
The study indicates that four weeks of daily exercise improves ability to perform tasks involving spatial memory, yet whether or not semantic memory (cognitive reasoning) is improved through such exercise is not discussed.
The Takeaway:
1) Studies indicate that an initial 120-minute exercise session enhances your brain's mechanism for storing energy and that this adaptation is maintained through daily sessions of 60 minute duration.
2) While procedural and episodic memory are improved through exercise, whether the same can be said for semantic memory (cognitive reasoning, quant ability, critical reasoning, etc) is not explicitly articulated. However, since it is known that the same brain structures (hippocampus and cortex) whose actions produce procedural and episodic memory also play a role in semantic memory, if procedural and episodic memory are enhanced with exercise, conceivably, so too does semantic memory through the same physiologic adaptations.
My Plan:
My exam is 25 days away, still enough time to fully experience the positive effects of regular exercise, I think. As someone who was a workout junky prior to my obsession with beating the GMAT, I believe I can get back into a routine seamlessly and without risk of injury. Therefore, I plan to implement the above and I will report back with how it works. My regimen will start with an endurance running session 120 minutes in duration followed by daily 60-minute maintenance sessions. Particularly, I'm looking for any perceived effect on my problem solving performance, speed, organization, and mental stamina.
I will continue to study and practice all areas tested, though at a reduced intensity, as advised by Ron earlier in this post.
--mj.
