Introduction: Aging is associated with chronic inflammation and metabolic dysfunction, contributing to functional and cognitive decline, especially in institutionalized older adults. Klotho, a longevity-associated protein with antioxidant and anti-inflammatory effects, may serve as a biomarker of healthy aging. Exercise programs integrating physical and cognitive components, such as dual-task resistance training (DTRT), may improve immunometabolic regulation, yet their effects in institutional settings remain underexplored.

Objectives: To investigate the effects of 12 weeks of DTRT followed by detraining on circulating Klotho levels in institutionalized older adults.

Methodology: This quasi-experimental, longitudinal study spanned 42 weeks and was divided into four phases: baseline (week 1), control (weeks 2–13), DTRT intervention (weeks 16–27), and detraining (weeks 29–41). Eleven older adults (5 men, 6 women) with a mean age of 81.9 ± 3.0 years, BMI of 23.8 ± 4.1 kg/m², and Mini-Mental State Examination (MMSE) score of 21.5 ± 5.8 were included. Serum Klotho levels were measured by ELISA. Data were analyzed using repeated-measures ANOVA with Bonferroni post hoc and Holm correction.

Results and Discussion: Post-intervention, a significant increase in serum Klotho levels was observed (p < 0.001), which remained elevated after detraining (p < 0.05), suggesting sustained immunometabolic adaptations induced by DTRT. Improvements were also observed in adiponectin, irisin, and sestrin-2 levels, alongside reduced IL-18, indicating an anti-inflammatory and metabolic benefit. These results highlight DTRT as a viable strategy to enhance biological resilience in institutionalized older adults, even after exercise cessation. Conclusion: DTRT proved effective in increasing and maintaining Klotho levels, supporting its use as an intervention to improve the health of institutionalized elderly individuals. Exercise strategies are essential for promoting metabolic resilience and addressing the challenges of aging.