Does Type of Exercise Matter in Terms of Benefits for Working Memory?
It has never been a secret that consistent exercise is one of the keys to living a balanced, reduced-stress, healthy lifestyle. If you are someone who works out often, you are probably familiar with the feeling of relaxation and lowering of stress that comes after a workout. It turns out that working out reduces emotional distress and provides resilience to stress and physical exercise plays a role in the prevention of many chronic diseases, including cardiovascular disease, depression, and hypertension among others. Basically, an increase in physical activity and exercise results in an improvement in general status of health. In general, the more physical exercise done, the greater the health benefits for the individual.
http://www.builtlean.com/2013/01/08/cardio-vs-weight-training/
Researchers at the University of Illinois were interested in comparing the health benefits, specifically on working memory, of differing forms of exercise. The two forms of exercise the researchers were interested in were acute aerobic physical exercise and resistance exercise. Aerobic exercise is exercise that utilizes oxygen as energy during exercise and is usually characterized as having light to medium intensity, calorie-burning, heart rate-increasing and beneficial to the cardiovascular system. Some examples of aerobic exercise are jogging or running, cycling, hiking, and swimming. Resistance exercise, or strength training, is exercise that causes muscle contraction and is usually used to build strength of muscle. Usually, resistance exercise refers to weight lifting or other exercises that provide resistance to muscles.
Working memory is the processing and manipulation aspect of short term memory and can also be described as the group of processes that are involved in storage and manipulation of information that can be retrieved within a relatively short period of time. Working memory is an example of an aspect of cognition that requires extensive executive control, which are aspects that require conscious awareness and are resource-limited, and therefore do not become automatic over time. Based on the paper, one way the executive control aspect of working memory can be tested is through the Sternberg working memory task, which involves having a participant memorize a series of items and then asked whether a probe item was in the list they had just memorized. The number of items in the first series can then be varied to test for reaction time.
In order to test the effects of two different types of exercise on working memory, the researchers used a modified Sternberg task. Individuals at seated rest, individuals who underwent acute aerobic exercise, and individuals who underwent resistance exercise each participated in the Sternberg task. The individuals at seated rest served as the control group as the experiment in order to test whether the effects of the other treatment groups actually significantly different from a baseline or normal treatment. The modified Sternberg task was given before each condition, immediately after each condition, and 30 minutes after each condition. Previous research had shown that any type of acute exercise had a significant effect on tasks requiring executive control, so the researchers hypothesized that both acute aerobic and acute resistance exercise would cause a decrease in response time in responses compared to seated rest.
The participants of this study were 21 undergraduate students from the University of Illinois. The modified Sternberg task used consisted of the students to memorize sets of 3, 5, and 7 capitalized consonants. The probe letter was a lowercase consonant with corresponding question marks around it depending on the length of the memory set.
The researchers found a statistically significant decrease in reaction time in the Sternberg task immediately after acute aerobic exercise and 30 minutes after acute aerobic exercise. However, they did not observe a decrease in reaction time in the same task in the people who did resistance exercise and the people who rested. This suggested that resistance exercise does not have as significant of an effect on the executive control part of working memory as acute aerobic exercise does. They also found that the greater the demand that was placed on working memory after acute aerobic exercise, the greater the improvement seen in performance on the working memory task; as set size was increased, improvements in cognitive performance were greater.
Pontifex, et al. 2009
This was not seen in individuals who were at rest and those who underwent resistance exercise. These results could potentially mean that different types of physical exercise have different effects on different cognitive processes or memory stores. Basically, aerobic exercise has benefits for the executive control portion of working memory while resistance exercise may have potential benefits for other types of memory.
So the next time you are deciding whether or not to go to the gym and exercise, and you want to improve the executive control of your working memory, it may be a better choice to go with aerobic exercise, rather than resistance exercise. Go running, hiking, or swimming rather than weightlifting for improvements in working memory.
Original source: http://www.setantacollege.com/wp-content/uploads/Journal_db/The%20Effect%20of%20Acute%20Aerobic%20and%20Resistance.pdf
Another blog post about the effects of exercise on cognition: http://web.colby.edu/cogblog/2013/04/29/the-effects-of-running-a-marathon-on-memory/
Literature Cited
Very well written and informative post, and I especially liked how you made the results of the study very clear. The finding that aerobic exercise may be the most beneficial for working memory is not all that surprising, seeing as the review you mentioned of cardiovascular exercise’s health benefits (Janssen & Leblanc, 2010) found overall health benefits as being higher in regard to aerobic exercise as opposed to resistance training. Even so, I was not aware of the significantly powerful cognitive boost provided by aerobic exercise. In terms of working memory and executive control, the notion that exercise can directly reduce reaction times by a substantial margin is a powerful one, and could have many implications for economic efficiency (e.g. having “exercise time” for company employees) and academics. This post made me wonder if the same effects would be exhibited on the Deese-Roediger-McDermott (DRM) paradigm after exercise, which is a paradigm used to examine the occurrence of false memories. My knowledge of the DRM paradigm (and its finding that a breakdown in controlled processes in patients such as in those with DAT increases rates of false recall) makes me assume that exercise would have a buffering effect and consequently reduce false memories. One problem that I had with the study was the possible confounding variable of personal differences among the participants. To explain this a little more, I noticed that there were multiple treatment groups that participated in each specific treatment condition, and as a consequence there may have been some bias among the participants because there was no baseline established for each participant.
It would be very interesting to see if this same paradigm—aerobic exercise provides more cognitive benefits than resistance training or no exercise—would still hold up in regard to other aspects of cognition such as attention or language abilities. I would predict that attention would exhibit the same sort of trend because executive control is extremely important in attention as well. Overall, great post.
This is an interesting post, particularly in the way the study brings matters of biology and psychology together. It makes a lot of sense that aerobic exercise yielded greater benefit to the working memory over anaerobic or none simply because of the role of oxygen. Aerobic exercise increases the flow of oxygen throughout the body, allowing more oxygen to be delivered to cells in all parts, including the brain. Greater flow of oxygen allows cells to work more efficiently, and thus has many positive effects on all of the body’s systems, meaning cognitive function improves as well.
Aerobic exercise also requires and builds more stamina. Increased stamina is often associated with a greater level of self-control, which is an important component of focus and attentional control. As you mentioned in the post, working memory requires extensive executive control, and this is what was tested in the study. Other studies that have included tasks requiring attentional control prior to the test of working memory showed that the initial task exhausted participants’ attentional control, but the opposite was true in this case. So it seems that a task like aerobic exercise where stamina is tested but the flow of oxygen through the body is simultaneously increased actually serves to benefit the individual’s ability to control his or her attention.