The hippocampus happens to be the major site for storage of memory – hence the impact of exercise on mental functioning. We also know that exercise improves brain health through accelerating the growth of new blood vessels in the brain, as well as enhancing the abundance and survival of these cells once they are born. Finally, it seems that consistent exercise has a particularly beneficial impact on the prefrontal cortex and medial temporal cortex—the “biggies” when it comes to higher order thinking and problem-solving capacities.
This is all well and good. We would all like to have bigger and better brains. But what does this have to do with better sleep quality? The immediate answer is a return to the point I have already made: everything works together. What helps one part of our body helps everything else. Nice try – but let’s try to get more specific. First, we can try a billiard shot that is banking off two walls before dropping in the pocket. We know that effective mental functioning improves our ability to live a successful life. It seems that the medial temporal cortex (along with the hippocampus through its role in operating our memory functions) plays an important role in our decision-making and problem-solving processes—as a companion to the prefrontal cortex (our center for rational thought).
If we can do a better job of making decisions and solving problems, then our interpersonal relationships are better, and we can do better work. As Sigmund Freud noted many years ago, successful living is all about two things: love and work. An effectively functioning brain helps us be better at achieving both of these life purposes. This in turn means that we are likely to be less anxious and stressed when we attempt to fall asleep – hence the two-wall bank shot into the sleep quality pocket.
We can get even more precise and offer a one wall bank shot analysis. It seems that the prefrontal cortex plays a major role in generating the slow waves found in stage three and stage four sleep. It is interesting to note that the prefrontal cortex tends to be deactivated during REM sleep (when dreams are likely to occur). This gets us into the regressive dynamics of dreams – but this analysis will have to wait until I turn to the nature and function of dreams in a later set of essays. The key point to be made here is that exercise plays an important role in the enhancement of prefrontal cortex functioning, which in turns enhances our ability to sleep deeply (stages three and four). Given that we often find it difficult to find stage three and four sleep as we grow older, it would seem to be particularly important that we engage in exercise as we grow older and seek high quality sleep.
This is the case to be made for the impact of exercise on mental functioning which, in turn, impacts sleep quality both indirectly (the two-bank shot) and directly (the one-bank shot). Once again, I remind all of us that everything links with everything else when it comes to health and physical/mental wellbeing.
Indirect Physical/Mental Impact: Stress-Reduction
As I have already noted, this fourth impact closely relates to several of the other component one pathways—specifically mindfulness/meditation and the pathway that I have directly labeled “stress-reduction.” I will spend a bit of time here describing the nature of stress and the way in which exercise can be engaged to reduce stress. When I turn specifically to stress-reduction, I will identify other ways in which we can reduce stress.
I begin by noting that stress is perhaps the easiest of the four impacts for us non-experts to comprehend: when we are under stress it is hard to fall asleep and stay asleep. Instead of counting sheep, we are counting how much we owe on our credit card or adding up all the injustices done to us by our incompetent boss. As Robert Sapolsky (2004) has so insightfully noted, we human beings are very adept at imagining lions of many varieties that threaten to attack us. This is one of the major conundrums of human existence. We are wonderfully adept at imagining and planning for a desirable future, as well as imaging and inventing new tools and societal structures and strategies; however, we are also adept at imagining horrible outcomes—and our body is not very good at distinguishing between real outcomes and those that are only imagined. Thus, we are once again living on the African savannah and easily imagine lions attaching us from all sides.
