Assessing Cognitive and Health Improvements in the Elderly Via Exercise (ACHIEVE) - Study.

In Colombia, a demographic transition is occurring that is reflected in an inverted population pyramid, with an increase in the proportion of older adults due to a better quality of life, as well as a decrease in the young population due to the low birth rate. These changes pose challenges for the healthcare system due to aging and its negative consequences for the body. The rate of aging has increased fourfold since 1950, which means a significant increase in the population of older adults compared to those under 15 years of age. Although exercise has been proven to have positive effects on the physical and cognitive health of older adults, there are still gaps in the literature concerning cognitive impairment in older adults, and the optimal dose to achieve maximum therapeutic potential has not been determined.

Therefore, the purpose of this research is to establish the optimal dose-response relationship to high-intensity exercise for improving cognition in older adults with mild cognitive impairment. A Randomized Controlled Clinical Trial with four groups will be conducted. One of the groups will serve as the control and will not receive treatment, focusing on occupational activities. The other three groups will be experimental, and the frequency and duration of exercise will be modified based on the World Health Organization (WHO) guidelines and a previous systematic research with meta-analysis. In the first experimental group (EG1), the WHO recommendations will be applied, consisting of 150 minutes of high-intensity exercise three times a week in sessions of 50 minutes each. In EG2, participants will perform high-intensity exercise twice a week, with a duration of 30 minutes per session. In EG3, high-intensity exercise will be performed four times per week in sessions of 50 minutes each. All experimental groups will receive high-intensity physical exercise interventions that combine aerobic and strength exercises adapted to the population. The sessions will be divided into three phases: warm-up, core phase, and cool-down.

Different sociodemographic, cognitive, and physical condition variables will be evaluated. All dependent variables will be measured before and after the intervention, and statistical analysis will determine which exercise prescription yielded the best results in terms of cognitive improvement. This research aims to provide valuable information about the optimal dose of high-intensity exercise to improve cognition in older adults with mild cognitive impairment in Colombia."

This research corresponds to an experimental study, a randomized single-blind controlled clinical trial, in which a total of 118 individuals, both men and women aged over 65, will participate. They will be divided into four groups: the control group (n = 31) and three experimental groups (n = 29 each). The variables will be measured for both groups using the same validated tools and evaluated by the same assessor to prevent information biases and differential misclassification. Evaluations will occur at the start of the intervention and immediately after its completion, with the results recorded in a data log. Subsequently, these results will be consolidated into an Excel database, with each participant assigned a code to ensure privacy while allowing for the necessary comparability.

Regarding the independent variables, we will address sociodemographic characteristics, clinical history, and the socio-familial assessment scale. As for the outcome variables, they are categorized into several areas: those related to health status will assess the relative risk of death due to comorbidity using the Charlson Comorbidity Index, health-related quality of life using the SF36 questionnaire, and Fried's frailty phenotype. Physical condition variables will be evaluated using the Senior Fitness Battery, gait and balance using the Tinetti Scale, and gait speed with the 6-minute walk test. Functional variables will be assessed using the Katz Index (activities of daily living), the Lawton \& Brody Index (instrumental activities of daily living), and Siu and Reuben's Physical Scale (advanced activities of daily living). For the cognitive variable, we will employ the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). Attention and executive functions will be measured using the Trail Making Test Part A and Part B. Verbal fluency will be assessed with the Verbal Fluency Test (VFT), while selective attention and concentration will be evaluated using the D2 test. Processing speed will be determined through the Digit Symbol Substitution Test (DSST).

Eligibility Criteria:
Inclusion Criteria:

* Men and women aged over 65 who voluntarily agree to participate in the study and are not engaged in any other physical exercise program
* Possess adequate physical autonomy to participate in the required physical activities for the study
* Exhibit mild cognitive impairment (with a score of \<25 on the Mini-Mental State Examination)
* Have the capacity to comprehend the instructions, programs, and protocols of this trial.

Exclusion Criteria:

* People with contraindications for physical or exercise tests will be excluded. This includes individuals diagnosed with pathologies such as cancer, pulmonary hypertension, renal failure, heart failure, orphan diseases, psychiatric conditions, neurological or cognitive impairments, or Human Immunodeficiency Virus (HIV/AIDS) infection or disease.
* Individuals who do not consent to participate in the study or have declined to endorse the use of their data for research purposes in the informed consent at the time of program entry will also be excluded.