Muscle Memory, but Not the Kind You Think
The stereotypes of the “nerd” and the “dumb jock” are some of the most pervasive in the media. The nerd is so un-athletic he might hurt himself walking to class, and the jock spends more time in the gym than in the library. While these stereotypes may be well known, the importance of exercise and health has increased over the last decade. Not only does exercise improve short-term mental concentration and mood by the release of endorphins, it is also being studied for long-term benefits. Even mainstream media has commented on exercise benefits, for example in the movie legally blonde displayed in figure 1.
Figure 1. Quote from Legally Blonde (2001) movie
One consequence of exercise is resting heart rate, as it measures the frequency of blood being pumped by the heart to organs and tissues, including the brain. During exercise one’s heart rate increases, and long-term consistent exercise decreases one’s heart rate as it has become more efficient at pumping blood. In other words, a good workout gives a stronger heart, so that during periods of rest and non-workouts the heart does not need to work so hard to get blood flowing. The brain is highly dependent on blood flow, and resting heart rate is an effective tool to measure the fuel supplied to the brain.
A few of the benefits of exercise have been studied and been shown to have positive long-term results. One example is an increase in attention spotlight, the ability to notice stimuli with high accuracy across one’s visual field, in athletes (Huttermann, 2014). An increase in zooming lens and size of the visual field allows individuals to widen one’s perceptive visually and notice actions or objects that previously may not have been spotted. This means as an individual is driving his or her visual field is wider, making an object or animal moving on the outside of the perception field will be noticed faster than for individuals with a smaller spotlight. More information can be found here.
The lower heart rate of the athletes studied is likely correlated with the increase in visual field and spatial awareness. In another study performed by the same researcher, he found those with higher resting heart rates had larger memory capacity and speed of accessing the information, a correlation found in improvements of long-term memory (Huttermann et al., 2014).
In another study by Huttermann et al., the resting heart rate and performance on word recall was studied. Participants were given three cues, and given feedback enhance the retrieval as shown by retrieval practice and the testing effect, more information found here. An example test had three cues: train-red, star-green and market-shelf. When train was shown participants were told, “not to think” of the correlated word and when given the word star they were told to “think” of green. The market-shelf pair was administrated as a baseline. Being told, “not to think” of the word actively suppresses the word and decreases the word recall, impairing memory. Memory suppression (inhibition) is necessary to retrieve the correct information and prevent irrelevant cues and knowledge from interfering with the correct cue.
Researchers found that participants with a higher resting heart rate performed better than lower resting heart rate on the “think” task, and had higher percentage of memory suppression. At the time of the test, a higher heart rate demonstrates effortful resources (energy, blood flow) being used for cognitive processes, as there is no physical activity involved. One possibility is that increasing the rate of blood flow allows for inhibition of irrelevant information from the brain, blocking the pathway, and the participant could only focus on the important word for the final cue recall (Gillie et al., 2013). As higher resting heart rate is indicative of higher levels of blood flow in the brain, which means more pathways are requiring fuel to be either activated or inhibited (Thayer & Lane, 2000). For the final recall, if told “no think” then overall the participants were less likely to remember. The experiment found that the lower resting heart rate participants had slower response times and lower levels of accuracy than the high resting heart rate group on ”think” cues, as there were able to suppress the irrelevant words.
What happens when these pathways are deprived of the fuel necessary to function? What does impairments to speech, the visual field, motor skills and coordination have in common with the heart? The answer is that the heart is the powerhouse of the brain, just like how the engine of a car influences the movement of the car, along with the air conditioning, radio, windows, etc. Without electricity and fuel being pumped in the engine, the car would not be able to function. A disturbance in the system demonstrates the importance of a functioning system of pathways from the brain to the heart (electricity for the car), and blood flow (gas in the car). As shown in figure 2 below, a stroke is an example when there is a blockage in the pathway from brain to heart, preventing blood flow.
Figure 2 displays an extreme case in which blood flow is blocked to the brain
The importance of flowing blood from the heart to the brain for cognitive processes is elaborated when there is an error or defect in the pathway. A stroke is an example when the lack of blood decreases oxygen to brain tissues and can result in speech errors, impairment to motor skills, visual field and coordination. The wide range of symptoms and consequences of a stroke illustrate the necessity for blood in the brain and the brain’s ability to efficiently use the blood supplied. Exercise is one method to increase the productivity of blood flow, as displayed by decreases in resting heart rate from a good workout.
Many studies have examined the positive effects of exercise. One prosperity of exercise is an increase in creativity during activity, a likely outgrowth from increases in heart rate (blood flow) and more fuel being supplied to cognitive processes. These benefits have influenced individuals like Steve Jobs to have walking meetings, more information found here. Exercise is essential not only for competing at high athletic venues, it is also important in cognitive processes including memory. One area of concern in decreasing memory is aging. Figure 3 illustrates the decline in heart rate overtime by gender.
Figure 3, decline in heart rate of men and women as a result of aging.
Improved cognition has been found to be a benefit of exercise along with improved cardiovascular fitness, regardless of the type of exercise (Fedor et al., 2015). As humans age, the average resting heart rate decreases, a likely byproduct of decreases in blood flow to the brain and weakening of the heart’s ability to pump blood. Overall, the separation between “nerd” mental ability and the “jock” physical ability appears to be outdated. Whether it is remember what to get at the grocery store or keeping a conversation, exercise has many benefits for cognitive function and heart rate can provide valuable insight into one’s cognitive abilities.
To read the original paper, click here
For additional blog post information on cognitive processes influenced by athletics, click here.
References:
Fedor, A., Garcia, S., & Gunstad, J. (2015). The effects of a brief, water-based exercise intervention on cognitive function in older adults. Archives of Clinical Neuropsychology, 30(2), 139-147. doi:10.1093/arclin/acv001
Hüttermann, S., Memmert, D., & Simons, D.J. (2014). The size and shape of the attentional “spotlight” varies with differences in sport expertise. Journal of Experimental Psychology: Applied, 20, 147-157.
Scheve, Tom. “Is There a Link between Exercise and Happiness?” Science. HowStuffWorks.com, n.d. Web. 14 Dec. 2015.
Picture 2: Retrieved from here
Picture 2: Retrieved from here
Picture 3: Retrieved from here
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