Examining the Heterogeneity of Exercise Response Among Sedentary Older Adults: A Descriptive Analysis.

Background: Significant heterogeneity in individual responses to exercise interventions provides an opportunity to identify individuals for whom modifications or adjunct therapies may be necessary. Here, we explore heterogeneity of exercise response among people with HIV (PWH) versus without HIV (control). Methods: The Exercise for Healthy Aging Study enrolled sedentary older PWH and controls (50-75 years old) for a 24-week aerobic and resistance exercise program. Responder groups were categorized based on minimally clinically important differences for cardiovascular (CV), strength, and lean mass (LM) outcomes. Descriptive statistics were used to examine baseline characteristics of the different groups. Results: 32 PWH and 37 controls (age 58 ± 6.5 years) were enrolled. CV nonresponders were more likely to have HIV infection, a greater comorbidity burden, and lower baseline CV fitness. Strength nonresponders had a lower comorbidity burden and greater strength at baseline. Comorbidities were similar across LM responder groups. CV and LM nonresponders had an increase in inflammatory markers from baseline to week 24 compared to decreased inflammatory markers among CV and LM responders. Conclusion: Lower CV fitness and HIV infection was more prevalent among those with poorer exercise response, suggesting that higher intensity or a prolonged duration of aerobic exercise may be required to overcome blunted CV adaptations particularly among PWH. Associations of CV and LM response with inflammatory markers should be further explored to determine if and when blocking inflammation might enhance exercise responses. Trial Registration: ClinicalTrials.gov identifier: NCT02404792.