Exercise as it relates to Disease/The effects of resistance exercise training on cognitive function and physical performance in cognitive frailty

This is a critique of the research article "Effects of Resistance Exercise Training on Cognitive Function and Physical Performance in Cognitive Frailty: A Randomized Controlled Trial" by D.H. Yoon, Jun-Young Lee and Wook Song from The journal of nutrition, health and ageing (2018).

What is the background to this research?
Frailty is an age-related syndrome, meaning biological reserve decreases due to the dysregulation of numerous physiological systems. Although with appropriate intervention and early detection, physical frailty is potentially reversible. Recent studies have discovered that there is a correlation between physical frailty and cognitive impairment in older adults. Due to the strong correlation, a new construct of cognitive frailty was established due to the presence of both physical frailty and cognitive impairment. However, there are no existing exercise interventions that are systematically suitable for both brain function and physical health promotion in older adults with cognitive frailty.

Furthermore, there is a lack of evidence and studies that determine the effects of exercise parameters on cognitive function. Thus, the research by Yoon et al., (2018) aimed to investigate the effects high-speed resistance exercise training has on older adults with cognitive frailty regarding their cognitive function and physical performance in hopes to provide knowledge about the specificity of recommended exercise specificity.

Where is the research from?
The research was conducted in Seoul and published by an accredited Journal of nutrition, health, and aging in 2018. The authors of this research are affiliated with credible organisations such as “Health and Exercise Science, Institute of Sports Science, SNU” and more. The authors have an accumulation of 275 publicised studies that cover a wide variety of disciplines. There was no report of any conflict of interest by the research group.

For the assessment of cognitive function, the research team implemented the Korean version of MMSE, CDR scales, and the neuropsychological test battery included the Korean version of the CERAD-K (Consortium to Establish a Registry for Alzheimer’s disease). The Korean versions were used due to the community-living participants.

What kind of research was this?
The research by Yoon et al. was a randomized controlled trial approved by the institutional review board of SNUBH. They recruited 65 participants aged 65 years and older. All the participants must be successful in the inclusion criteria and additional examinations. The participants were randomly assigned to either the high-speed resistance exercise intervention or the control group (balance and resistance band stretching). Randomised controlled trials are given the highest level of evidence as they have an unbiased system and a decreased risk of systematic error. The statistical analysis included Tukey's post hoc test, determining the pairwise differences between the mean values. This procedure led to a p-value of less than 0.05, indicating statistical significance.

What did the research involve?
The community-living participants were older adults with cognitive frailty. During the 2 different 4-month interventions specific measurements were recorded. These measurements included frailty phenotype (BMI, slowness, weakness, exhaustion, low physical activity), cognitive function (memory, processing speed, cognitive flexibility, working memory, executive function), physical function (SPPB, TUG, gait speed), and muscle strength (grip strength, knee extension strength). These measurements were taken at baseline, 8 weeks, and 16 weeks.

The high-speed resistance training group had to undergo independent exercise conducted 3 times a week for 16 weeks using resistant bands. Conversely, the control group were instructed to live their normal lives and take part in static and dynamic stretching using resistance bands for 1-hour twice a week over 16 weeks.

The existing limitations included the limited sample size of participants in the research along with the relatively short period of exercise intervention. For participants to partake in the research they must’ve answered “no” to all the following criteria: history of depression, chronic disease, degenerative neurologic disease, hospitalisation for any reason in the past 12 months, illiterate, dementia, stroke, and other cardiopulmonary diseases.

What were the basic results?
The high-speed resistance exercise group had a significant increase in performance regarding their tests for cognitive function (processing speed and executive functions), physical function (short physical performance battery (SPPB), TUG, and gait speed) and muscle strength (grip and knee extension strength). However, there were no significant changes in the test for frailty scores for both groups.

In their discussion Yoon et al., articulate the results they gathered and compared them to other accredited studies to further reinforce the results. They state that regular physical exercise will inevitably cause a positive effect on both human biology and psychology. They also acknowledged the limitations of the research as well as the need for further investigations of other multidomain interventions.

What conclusions can we take from this research?
According to Yoon et al., this was the first intervention trial that assessed the effects of a specific resistance exercise intervention in treating cognitive frailty. With this proclamation, the research provided further delineation of cognitive function and frailty in retrospect with high-speed resistance exercise training. Previous studies have identified the significance of increased physical activity for older adults with cognitive frailty. Physical activity is a protective barrier against further progression of cognitive frailty. Neurobiological conditions such as glucose metabolism, sarcopenia and insulin resistance were discovered to be optimised during physical activity, leading to the decrease of cognitive frailty progression. The result of this study offers a specific type of exercise training intervention that will provide an effective methodology for reversing cognitive frailty in older adults, whilst supporting the correlation between physical activity and cognitive frailty.

Physical activity and specific exercise interventions are essential for older adults as they have positive multidomain effects including cognitive function, physical function, and muscle strength. Having the ability to identify older adults that suffer from cognitive frailty and the effective intervention for their primary care setting is crucial in decreasing their level of cognitive frailty.

Practical advice
Previous studies, including this trial      have determined that when older adults participate in regular physical activity, their cognitive function and physical function increase and their cognitive frailty decreases. Regular moderate-vigorous exercise (1hr – 3 times a week), such as high-speed resistance exercise should be recommended to older adults with cognitive frailty. Health and safety precautions are critical, thus supervision by an accredited exercise instructor should be present to provide any assistance. Effective exercises include :


 * Seated row
 * One leg press
 * Pec dec fly's
 * Seated leg raise
 * Lateral raise
 * Squats
 * Bridges

Monitoring progression can include regular BMI calculations and tracking overload progressions. But if professional assessments are available, frailty phenotype, cognitive functions, physical functions, and muscle strength can be tested to monitor the progress.

It would be recommended to participate in such exercise interventions in the presence of medical teams and accredited specialists due to the risks that can arise for older adults. Thus, proper inclusion/exclusion criteria should be completed as well as additional safety protocols.

Further information/resources
Resources for cognitive frailty

Additional understandings of Cognitive Frailty

Different prevention methods

Resources for preventing cognitive frailty

Physical activity prevention

Effects of physical exercise