Publishing a study in GeroScience featuring people over 80 years old, researchers have described a link between physical fitness and maintenance of specific brain functions.
Executive functions
This paper begins with a description of executive functions, the basic abilities involved in performing the fundamental goal-oriented behaviors necessary for everyday life. It is obvious how this can strongly affect independence in later life, including among older people with mild cognitive impairment [1]. Previous work has linked physical fitness to improved cognition in older people [2], particularly in executive functions [3]. However, these researchers note that most of these studies were performed among comparatively younger people rather than the very old.
Therefore, they sought to understand how two essential parts of executive function, attentional control and response inhibition, were affected by physical function in aging. These are the abilities to focus the attention on only relevant things and to stop automatic responses from occurring. Both of these abilities are challenged by the flanker task, iin which participants are instructed to react only to a disc of a central color while discs of different colors surround it.
A simple test with detailed data
After screening for the ability to perform this task and for disqualifying conditions, a total of 115 participants with an average age of 82.4 years had been included in this study. To test cardiorespiratory fitness, they engaged in a step test in which they lifted their knees to a specific height as rapidly as they could for two minutes. These participants also had electroencephalogram (EEG) measurements taken, and those were compared to their performance during the study.
The flanker test was performed in three different ways: congruently, in which the colors of the flanking discs were the same as the central disc, neutrally, in which they were an entirely different color, and incongruently, in which they were the opposite color. As expected, there were slight differences in the participants’ EEG results in each of these three variants.
In a mediation analysis, physical fitness was found to improve results in all three of the tests. Examining the EEG results, the researchers found that this improvement had occurred due to an improvement in early visual processing capability. The fitter people had better immediate reaction times. They were also found to have stronger motor-related potentials in the cortex, but this did not seem to be connected with improved task performance.
Interestingly, these researchers report a lack of results in later cognitive processing, noting that their results go against previous work showing that such correlations exist [4]. They suggest that their use of a fitness task, rather than relying on self-reported fitness, may account for the different results. Additionally, this study recruited people who were considerably older.
Use it or lose it?
The researchers speculate that their results demonstrate that continued performance in the “oldest old” requires regular use of the specific brain regions involved. In other words, the reason that more physically fit older people have better motor-related and immediate visual processing functions is likely to be that they are using them regularly. Other brain regions responsible for more detailed cognition, the researchers surmise, should be maintained through activities that exercise the mind.
Literature
[1] Mansbach, W. E., & Mace, R. A. (2019). Predicting functional dependence in mild cognitive impairment: Differential contributions of memory and executive functions. The Gerontologist, 59(5), 925-935.
[2] Bherer, L., Erickson, K. I., & Liu-Ambrose, T. (2013). A review of the effects of physical activity and exercise on cognitive and brain functions in older adults. Journal of aging research, 2013.
[3] Colcombe, S., & Kramer, A. F. (2003). Fitness effects on the cognitive function of older adults: a meta-analytic study. Psychological science, 14(2), 125-130.
[4] Winneke, A. H., Godde, B., Reuter, E. M., Vieluf, S., & Voelcker-Rehage, C. (2012). The association between physical activity and attentional control in younger and older middle-aged adults. GeroPsych.
