Feasibility of HIIT in Older Adults with HIV and Hypertension

Life expectancy for people with HIV (PWH) has increased in the antiretroviral therapy (ART) era and shifted the demography of the HIV epidemic toward the aging population. By the year 2030, an estimated 70% of PWH in the United States will be at least 50 years of age, thus implicating age-related comorbidities as a potential challenge for PWH. In particular, hypertension represents a major co-morbidity burden among PWH. Regular physical activity improves function in adult populations with comorbidities and prevents functional declines.

Maintenance of functional status, determined by measures of physical performance, is a good predictor of cardiovascular outcomes among older PWH with co-occurring hypertension. Exercise is the only intervention with evidence to support its use in treating age-related functional declines. Exercise is a strategy employed by PWH and rehabilitation professionals to address the functional decline and improve the health and quality of life of those individuals. Exercise interventions in PWH support the evidence that exercise can improve cardiovascular, metabolic, and functional measures in younger PWH. Though meeting the recommended guidelines for regular physical activity in older adults is feasible, the repercussions of high-intensity interval training in improving physical function are unknown despite evidence displaying functional improvements following low and moderate-intensity interventions.

While many exercise studies have reflected the benefit of six to twelve weeks of exercise, many report that the results are limited to the participants who are motivated with good compliance and completion profiles. In real-world situations, adherence to exercise, particularly high-intensity exercise, may fall below desirable levels and hinder the effectiveness of the programs. This may be due, in part, to perceived benefits and barriers to exercise in older PWH. Despite the growing body of research aimed at determinants of adherence to pharmaceutical treatment, adherence to exercise among PWH remains an under-researched area.

The purpose here is to evaluate the efficacy and efficacy of a high-intensity interval training intervention for improving the physical function of older PWH and co-occurring hypertension. The central hypothesis is that high-intensity exercise will improve functional decrements of older PWH. An evaluation of high-intensity interval training in PWH may be important as this population has impairment in functional outcomes compared with age-matched uninfected controls, with even greater impairments among older PWH. Underlying inflammation, pain, and skeletal muscle degradation related to HIV suggest that older PWH may require higher doses of exercise to restore or achieve levels of physical function. Thus, the objective of this pilot application is to evaluate the efficacy and feasibility of short-term high-intensity interval training among 15-20 older PWH > 50 years with co-occurring hypertension, recruited from CNICS. To achieve this objective, the investigators propose to conduct a pilot study to address the following specific aims, which are crucial to designing future studies:

Specific Aim 1: To assess the integrity of the study protocol, including safety, adherence to the interventions, and retention to study visits, in order to develop standard operating procedures for guidance of a future trial. Additionally the investigators will determine participant perceived benefits and barriers, assessed by the Exercise Benefits and Barriers Scale.

Specific Aim 2: To assess the variance of secondary outcomes and effects of the intervention on outcomes including 1) 6-minute walk test, 2) lower extremity function, assessed by the Short Physical Performance Battery (SPPB), 3) skeletal muscle strength and endurance, assessed by isokinetic muscle testing, 4) chronic pain, evaluated by the Brief Pain Inventory and Pain assessments, 5) markers of vascular health (e.g., arterial stiffness), 6) circulating indices of inflammation (e.g. inflammatory profile [IL-1β, TNF-α, IL-6, CRP, IL-8, IL-10], skeletal muscle degradation [creatine kinase], and metabolism [fasting glucose, HA1C, lactate, and fasting cholesterol].