Effects of Physical Exercise on Telomere Length in Healthy Adults: Systematic Review, Meta-Analysis, and Meta-Regression.

BACKGROUND: Physical exercise is one of the main nonpharmacological treatments for most pathologies. In addition, physical exercise is beneficial in the prevention of various diseases. The impact of physical exercise has been widely studied; however, existing meta-analyses have included diverse and heterogeneous samples. Therefore, to our knowledge, this is the first meta-analysis to evaluate the impact of different physical exercise modalities on telomere length in healthy populations. OBJECTIVE: In this review, we aimed to determine the effect of physical exercise on telomere length in a healthy population through a meta-analysis of randomized controlled trials. METHODS: A systematic review with meta-analysis and meta-regression of the published literature on the impact of physical exercise on telomere length in a healthy population was performed. PubMed, Cochrane Library, SCOPUS, Web of Science, and Embase databases were searched for eligible studies. Methodological quality was evaluated using the Risk Of Bias In Nonrandomized Studies of Interventions and the risk-of-bias tool for randomized trials. Finally, the certainty of our findings (closeness of the estimated effect to the true effect) was evaluated using Grading of Recommendations, Assessment, Development, and Evaluations (GRADE). RESULTS: We included 9 trials that met the inclusion criteria with fair methodological quality. Random-effects model analysis was used to quantify the difference in telomere length between the exercise and sham groups. Meta-analysis showed that exercise did not significantly increase telomere length compared with the control intervention (mean difference=0.0058, 95% CI -0.05 to 0.06; P=.83). Subgroup analysis suggested that high-intensity interventional exercise significantly increased telomere length compared with the control intervention in healthy individuals (mean difference=0.15, 95% CI 0.03-0.26; P=.01). Furthermore, 56% of the studies had a high risk of bias. Certainty was graded from low to very low for most of the outcomes. CONCLUSIONS: The findings of this systematic review and meta-analysis suggest that high-intensity interval training seems to have a positive effect on telomere length compared with other types of exercise such as resistance training or aerobic exercise in a healthy population. TRIAL REGISTRATION: PROSPERO CRD42022364518; http://tinyurl.com/4fwb85ff.

An Item Response Theory Analysis of the Wisconsin Card Sorting Test in Normal Aging, Alzheimer's Disease and Parkinson's Disease: Neurophysiological Approach.

The Wisconsin Card Sorting Test (WCST) is widely used to assess executive function, specifically mental flexibility. Item Response Theory (IRT) has several advantages over classical test theory, including the invariance of the measure. This study aimed to apply IRT to study the psychometric properties of WCST in control subjects and patients with idiopathic Parkinson's disease (PD) and Alzheimer's disease (AD). The sample consisted of 86 controls, 77 Parkinson's disease subjects, and 155 AD subjects. The Rasch model was applied to binary data from the conversion to percentiles adjusted for age and schooling. The R program was used to calibrate the difficulty parameter. The characteristic curves of the items and the estimation of the difficulty parameter for each diagnostic group were obtained. WCST makes it possible to separate between different skill levels among the three diagnostic entities and its application may be useful for other neuropsychological tests. In conclusion, WCST has good clinical sensitivity and excellent discriminant validity in the groups under study, making it possible to separate them between different levels of ability or latent trait. Its application may be useful for other neuropsychological tests.

Analysis of Telomere Length and Its Implication in Neurocognitive Functions in Elderly Women.

During the normal aging process, a series of events occur, such as a decrease in telomere length and a decrease in various cognitive functions, such as attention, memory, or perceptual-motor speed. Several studies have attempted to establish a correlation between both variables; however, there is considerable controversy in the scientific literature. The aim of our study was to establish a correlation between the scores obtained in the following different cognitive tests: the Mini-Mental State Examination, the Benton Visual Retention Test, the Trail Making Test, the Rey Auditory Verbal Learning Test, the Stroop Test, and the measurement of telomere length. The sample consisted of a total of 41 physically active, healthy women, with a mean age of 71.21 (±4.32) and of 33 physically inactive, healthy women, with a mean age of 72.70 (±4.13). Our results indicate that there is no correlation between the scores obtained by the women in either group and their telomere length. Therefore, it is not possible to conclude that telomere length can be correlated with cognitive performance.

Effects of Physical Exercise on Cognition and Telomere Length in Healthy Older Women.

BACKGROUND: Physical exercise is an effective measure for preventing the onset of cognitive decline and has a direct influence on the aging process. The purpose of this study was to assess the effect of a 6-month physical exercise program on cognition and telomere length in adults over 65 years of age. METHOD: Seventy-four healthy women were separated into two groups: 41 were included in the intervention group (IG) (72.70 ± 4.127 years and 8.18 ± 1.551 years of education) and 33 in the control group (CG) (71.21 ± 4.127 years and 8.42 ± 2.562). The participants included within the IG carried out three sessions of physical exercise per week for six months. Cognitive function was assessed using the Mini-Mental State Examination (MMSE), the Stroop test and the Trail Making Test (TMT). Saliva samples were taken and analyzed and relative telomere length was calculated. Those conducting the analysis were blind to the group to which the participants had been assigned. RESULTS: An improvement was observed in global cognitive function, in both attentional and executive functions, in the group of adults doing physical exercise as compared to the control group. Six months after the physical exercise program had finished, relative telomere length was found to have increased in the participants in the intervention group. CONCLUSION: Physical exercise programs can lead to an improvement in both cognitive functions and telomere length.

Cognitive reserve and lifestyle in Spanish individuals with sporadic Alzheimer's disease.

BACKGROUND: Some authors suggest that besides the fundamental components, cognitive reserve (CR) also reflects the influence of a combination of factors that improve mental health. METHOD: After obtaining the sociodemographic profile of each participant and evaluating their neurologic and neuropsychologic abilities, first, homogeneity analysis was used as a technique to select variables and reduce the number of categories with similar behavior; then CR construct was identified through a latent class analysis model. It was then possible to categorize participants according to their level in this construct and compare the neuropsychological performance of the subgroups that emerged, using a t test of differences of means for independent samples. RESULTS: Participants with Alzheimer's disease with low CR scores exhibited significantly greater deficits in measures of memory, attention, and language than patients with high CR. CONCLUSIONS: Our results ratify the effect of higher education, higher professional performance, and ludic activities on CR.

Reserva cognitiva y demencia / Cognitive reserve and dementia

Según los estudios demográficos se calcula que en nuestro país en el año 2020 la proporción del número de ancianos será del 20-25 por ciento. Este envejecimiento de la población comporta un incremento notable de las enfermedades ligadas a la edad, donde se incluyen los procesos neurodegenerativos. Se ha sugerido que la Reserva Cognitiva es un mecanismo que vincula los niveles educativos bajos con un riesgo mayor de padecer un proceso neurodegenerativo. La reserva, o la habilidad del cerebro de tolerar mejor los efectos de la patología de la demencia, puede ser el resultado de una habilidad innata o de los efectos de las experiencias vividas, tales como la educación o la ocupación laboral. Algunos autores sugieren el término "reserva cerebral" para hablar de ideas más pasivas de reserva, basándose en características propias del individuo tales como el tamaño cerebral, el número de neuronas o la densidad sináptica que ayudan a compensar posibles enfermedades degenerativas del Sistema Nervioso Central. En este trabajo, pretendemos exponer aquellas posibles variables que soportan la teoría de esta hipótesis (AU)