Over the past few years we have all heard of one study or another that says exercise is good for your brain function. Well now there is a new meta-analysis that adds to the evidence that exercise improves cognitive function for adults older than 50. So whether you are training older adults, are over 50 yourself, worried about getting older or just looking for material to email to your parents to harass them into exercising now you have the evidence to guilt them or yourself into getting off the sofa and breaking a sweat.
For those of you who aren’t research geeks like me, a quick primer on what a meta-analysis is. It is a type of study that takes the results for a number of different studies and combines their results to form a single conclusion that has more statistical power then the individual studies. An individual study might only look at a few particular variables regarding the issue at hand. It may have a limited population of subjects and be prone to certain types of errors or biases. Often different studies on the same topic will come up with different results and conclusions creating a situation where you don’t know which studies are correct and should be followed. A meta-analysis tries to overcome these limitations by compiling multiple studies, often with differing results, and analyses them in a way that balances out these differences resulting in a final conclusion that accounts for all of the evidence available. It is still limited by the information in the studies it complies but for the primary question at hand, it generally offers a more complete conclusion.
In this particular study the authors looked at the effects of different forms of exercise including aerobic, resistance, a combination of both, tai chi and yoga on cognitive function. They also addressed the affect of different training variables including duration, frequency, intensity and length of the exercise session. Ultimately they were interested in determining the impact of all of these different factors on global cognition as well as the specific areas of attention (sustained alertness, the ability to process information rapidly), executive function (cognitive processes responsible for the initiation and monitoring of goal-oriented behaviors), memory (storage and retrieval of information) and working memory (short –term manipulations of encountered information).
The analysis was limited to studies where the exercise programs were actually supervised and lasted at least 4 weeks. This allows for some measure of assurance that the subjects actually did the prescribed exercise as intended and for a long enough period of time for the exercise to have a measurable effect. Studies with subjects of differing cognitive abilities were included though samples with subjects who had other neurological conditions such as strokes or mental illness such as depression were not included. Ultimately 36 studies were included in the final quantitative analysis.
As for the good news, aerobic exercise, resistance training, a combination of the two and tai chi all were found to have a positive effect and improved cognitive function in adults over 50. The effect was seen regardless of the cognitive status of the participants. A particularly pronounced effect from resistance training was seen for executive function, memory and working memory. The results for Tai chi were very promising but the number of studies that focused on that intervention were small so further research in the area is needed but the initial suggestion is that it could be a very powerful intervention, especially useful for those individuals who cannot perform more traditional aerobic and resistance training due to physical limitations.
When it comes to time, moderate length exercise sessions of 45-60 minutes were far and away the most beneficial. This doesn’t mean shorter or longer sessions are not good for your brain, just that the results of this study show the most improvements overall working in that moderate range.
Both moderate and vigorous intensity were found to have similar positive impacts while low intensity exercise did not have a statistically significant impact. This tends to go along with the results we have been seeing in much of the HIIT research we have been talking about recently. When individuals have the capacity to go harder, the results seem to be greater though when looking at overall populations, the impact of moderate intensity appears to have overall similar effects. Considering the psychology of most people, being able to achieve such positive benefits with moderate effort means we can reach that huge segment of people in the middle who are willing to exercise but not push themselves to that vigorous level. While the low intensity work did not reach a level of statistical significance, the trend was still positive and it is far too early to say that exercise at a low intensity doesn’t have a cognitive effect.
All weekly frequencies of exercise as well as the overall length of time of the intervention showed significant impacts.
There you have it, aerobic and resistance training done for 45-60 minutes on as many days of the week as possible at a moderate to vigorous level of intensity improves your brain function. Now you just need to remember to get up and do it and have the drive and commitment to focusing on your goal and following through with it. If only there was something you could do that would improve your memory and executive function.
Works cited: Northey, J., Cherbuin, N., Pumpa, K., Smee, J. and Rattray, B. (2017) Exercise interventions for cognitive function in adults older than 50: a systematic review with meta-analysis. Br J Sports Med. April 24