The health benefits of exercise have been well-established in many current studies, and people of all ages are encouraged to “chronically” exercise. These benefits can apply not only to cardiovascular, strength, and overall physical health but also to brain health. Neuroplasticity, or brain plasticity, is important to learning and growth and our brains are most plastic in infancy and early childhood (Britannica.com). Cognitive functioning can decline in late adulthood. Thus, efforts to improve neuroplasticity can mean sustained memory, processing speed, and ability to organize and perform complex tasks.
The goal of this study was to identify the role of aerobic training (AT) and resistance training (RT) on neuroplasticity in healthy adults and in adults with specific cognitive disorders. Of particular interest was the role of exercise intensity on neuroplasticity. Neuroplasticity is foundational for improvements in motor, cognitive, and behavioral functions, and more intense exercise may yield more profound results.
For the purposes of the study, AT is defined as “repetition of bouts of running, cycling, rowing, and swimming” whereas RT is “overcoming external loads by forceful muscle contractions” (p. 2). Neuroplasticity is “the brains ability to create new and reorganize existing synaptic connections” (p. 2). Prior animal studies have found exercise intensity was scalable leading to increasingly better outcomes, but will the same hold true for humans?
Outcomes of interest included motor outcomes, such as grip strength, walking speed, oxygen uptake, and muscle power, and cognitive outcomes, such as executive function, processing speed, and memory.
This meta-analysis included 50 studies of 2283 participants. The mean age was 53, with a range of 18-77 years old, and 60% were female. Studies used AT, RT, or both with either low- or high-intensity training. The training period ranged from 3-52 weeks, which must be considered when looking at results. All studies included a control group. In addition to healthy adults, some studies included adults with multiple sclerosis, Parkinson’s disease, and stroke.
Results of the meta-analysis showed that both AT and RT improved neuroplasticity for healthy young and old adults and for adults with multiple sclerosis, Parkinson’s, and stroke. However, intensity was important: low-intensity exercise did not lead to improved neuroplasticity for any of the groups. What aspects of neuroplasticity were impacted? Based on post-intervention assessments, motor skills were positively impacted by exercise, but there was no corresponding improvement in cognitive abilities. The motor skills improvement was observed only in healthy younger and older participants.
In any meta-analysis, there are potentially confounding factors due to the various ways in which variables are assessed in each study. For example, “exercise intensity” may be measured differently across studies and health status may be unclear. The results of the meta-analysis are not necessarily definitive and further study is always warranted to more accurately assess connections between interventions and outcomes.
Hortobágyi, T., Vetrovsky, T., Balbim, G. M., Silva, N. C. B. S., Manca, A., Deriu, F., … & Granacher, U. (2022). The impact of aerobic and resistance training intensity on markers of neuroplasticity in health and disease. Ageing Research Reviews, 101698.
©Jennie Dilworth, Ph.D