The Impact of Aerobic Exercise Program on Immunosenescence Institutionalized Older Adults

The Impact of Aerobic Exercise Program on Immunosenescence in Institutionalized Older Adults: a Study Protocol for Randomized Controlled Trials

Background: Immunosenescence is an age-related decline in immune function, associated with chronic low-grade inflammation, increased morbidity, and functional impairment in older adults. Aerobic exercise has been proposed as an effective non-pharmacological strategy to counteract these alterations; however, evidence from randomized-controlled trials (RCTs), particularly in institutionalized elderly populations, remains scarce and methodologically limited.

Objective: This study protocol aims to investigate the effects of short- and medium-term aerobic exercise programs on immunosenescence in institutionalized older adults, as well as to analyze the impact of a detraining period and a subsequent reintervention.

Methods: A stratified RCT will be conducted with institutionalized adults aged ≥60 years, randomly allocated to an aerobic exercise group or a control group. The intervention consists of a supervised 12-week moderate-intensity aerobic exercise program (three sessions/week), followed by a 4-week detraining period and a 4-week reintervention. Assessments will be performed at five time points. Primary outcomes include immunological and analytical parameters assessed by spectral flow cytometry and multiplex cytokine analysis. Secondary outcomes include anthropometry, functional capacity, hemodynamic parameters, heart rate variability, and psychological indicators.

Expected Results: Aerobic exercise is expected to induce favorable immunological adaptations, partially reverse immunosenescence, and improve functional and psychosocial outcomes.

This investigation will be based on a stratified randomized intervention. Participants will initially be stratified according to clinical conditions. Within each stratum, a 1:1 randomization will be performed to the experimental group (AERG) and control group (CG) using software SPSS. The randomization sequence will be generated using variable-size permuted blocks to ensure a balance in the number of participants in each group and reduce the risk of allocation predictability. Randomization will be performed by a researcher external to the data collection and intervention implementation process. The randomization will be stored in an encrypted file until the start of the intervention, ensuring allocation concealment.

An aerobic exercise program (12 weeks) will be implemented, followed by a detraining period (4 weeks) and the implementation of a second intervention (4 weeks). Primary outcomes include analysis of analytical parameters and cellular assessment. Secondary outcomes include anthropometric analysis, functional capacity, hemodynamic parameters, and psychological parameters. All participants will be assessed at five distinct time points, as shown in Figure 1: before the intervention (T0), at 6 weeks (T6) and at 12 weeks (T12) of intervention, after the detraining period (T16), and after the second intervention (T20).

Inclusion criteria:

Participants must be aged 60 years or older and institutionalized. Studying institutionalised older adults ensures greater uniformity in diet, daily routines, behaviours, and environmental exposures, thereby minimising the impact of external factors other than the exercise intervention.

Exclusion criteria:

Participants will be excluded if they have acute conditions that may affect their immune or inflammatory responses. These conditions include recent trauma or surgery (within the previous six months), recent blood transfusions (within the previous month), acute infections (such as respiratory, gastrointestinal, or urinary infections), recent vaccinations, and the use of medications that may interfere with immune responses (such as immunomodulators, systemic corticosteroids, methotrexate, and biologics).