Association of chronotropic incompetence with reduced cardiorespiratory fitness in older adults with HIV.

OBJECTIVE: Understanding the physiological drivers of reduced cardiorespiratory fitness in people with HIV (PWH) will inform strategies to optimize healthspan. Chronotropic incompetence is common in heart failure and associated with low cardiorespiratory fitness yet is understudied in PWH. The objective was to determine the prevalence of chronotropic incompetence and its relationship with cardiorespiratory fitness. DESIGN: Participants were PWH at least 50 years of age with no prior history of heart failure or coronary heart disease who were enrolled in a randomized exercise trial. Baseline cardiopulmonary exercise testing (CPET) was used to measure cardiorespiratory fitness as peak oxygen consumption (VO2peak) and calculate the chronotropic index from heart rate values. Chronotropic incompetence was defined as an index less than 80%. RESULTS: The 74 participants were on average 61 years old, 80% Black or African American, and 93% men. Chronotropic incompetence was present in 31.1%. VO2peak was significantly lower among participants with chronotropic incompetence compared with participants without chronotropic incompetence [mean (SD) ml/min/kg: 20.9 (5.1) vs. 25.0 (4.5), P = 0.001]. Linear regression showed that chronotropic incompetence and age were independent predictors of VO2peak, but smoking and comorbidity were not. The chronotropic index correlated with VO2peak (r = 0.48, P < 0.001). CONCLUSION: Among older PWH without heart failure or coronary heart disease, chronotropic incompetence was present in approximately one-third of individuals and was associated with clinically relevant impaired cardiorespiratory fitness. Investigation of chronotropic incompetence in large cohorts which includes PWH and heart failure may contribute to strategies that promote healthy aging with HIV infection and offer a preclinical window for intervention.

Pilot study of functional circuit exercise in older adults.

Sustainable exercise strategies are needed for older adults to maintain aerobic capacity and strength. The objective of this pilot in 6 adults ≥ 65 years of age was to determine the feasibility and preliminary efficacy of high-intensity functional circuit training which does not require stationary equipment. Instructor-led small group exercise classes were held 3x/week for 12 weeks using weight-bearing exercises performed in a circuit format at ratings of perceived exertion (RPE) of 6-8/10. All 6 participants completed the pilot and showed significant improvements by the Wilcoxon signed-rank test. The six-minute walk distance increased 10.5%. Timed arm curl and chair stands increased 26.8% and 30.3% (all p ≤ 0.03). These preliminary findings suggest that high-intensity functional circuit exercise is feasible in older adults and increases functional measures of aerobic capacity and strength. Further research is warranted to develop this strategy which has the potential for broad dissemination without the need for a traditional exercise facility.

Telehealth Exercise Intervention in Older Adults With HIV: Protocol of a Multisite Randomized Trial.

ABSTRACT: People with HIV (PWH) have reduced cardiorespiratory fitness, but a high intensity, easily disseminated exercise program has not yet been successfully developed in older PWH. The purpose of this article is to describe a synchronous telehealth exercise intervention in older PWH, delivered from one medical center to two other centers. Eighty older PWH (≥50 years) on antiretroviral therapy will be randomized to exercise or delayed entry control groups. Functional circuit exercise training, which does not entail stationary equipment, will be provided by real-time videoconferencing, 3 times weekly for 12 weeks, to small groups. Continuous remote telemonitoring of heart rate will ensure high exercise intensity. We hypothesize that telehealth exercise will be feasible and increase cardiorespiratory fitness and reduce sarcopenia and frailty. Findings will provide new insight to target successful aging in older PWH and can also be widely disseminated to PWH of any age or other patient populations.

Assessing Moderate to Vigorous Physical Activity in Older Adults: Validity of a Commercial Activity Tracker.

Purpose: Despite the potential for commercial activity devices to promote moderate to vigorous physical activity (MVPA), limited information is available in older adults, a high-priority target population with unique gait dynamics and energy expenditure. The study purpose was to investigate the content validity of the Garmin Vivosmart HR device for step counts and MVPA in adults ≥65 years of age in free-living conditions. Methods: Thirty-five participants (M age= 73.7 (6.3) years) wore Garmin and ActiGraph GT3X+ devices for a minimum of 2 days. Accuracy and intra-person reliability were tested against a hip worn ActiGraph device. Separate analyses were conducted using different accelerometer cut-off values to define MVPA, a population-based threshold (≥2,020 counts/minute) and a recommended threshold for older adults (≥1,013 counts/minute). Results: Overall, the Garmin device overestimated MVPA compared with the hip-worn ActiGraph. However, the difference was small using the lower, age-specific, MVPA cut-off value [median (IQR) daily minutes; 50(85) vs. 32(49), p = 0.35] in contrast to the normative standard (50(85) vs. 7(24), p < 0.001). Regardless of the MVPA cut-off, intraclass correlation showed poor reliability [ICC (95% CI); 0.16(-0.40, 0.55) to 0.35(-0.32, 0.7)] which was supported by Bland-Altman plots. Garmin step count was both accurate (M step difference: 178.0, p = 0.22) and reliable [ICC (95% CI; 0.94) (0.88, 0.97)]. Conclusion: Results support the accuracy of a commercial activity device to measure MVPA in older adults but further research in diverse patient populations is needed to determine clinical utility and reliability over time.

Feasibility and effects of high-intensity interval training in older adults living with HIV.

Adults with HIV on therapy can live a normal lifespan but exhibit advanced ageing which includes reduced cardiorespiratory fitness. Our objective was to determine the feasibility and effects of high-intensity interval training (HIIT) combined with resistance training (RT) in older adults with HIV. We conducted a cross-over pilot study within a randomized exercise trial in sedentary adults with HIV ≥50 years of age. First, participants were randomized to 4 months of continuous high-intensity aerobic exercise (AEX) and RT 3x/week or standard of care control. Then, the control group completed 4 months of HIIT + RT (3x/week). Among the 32 individuals enrolled, 26 eligible participants were randomized. Most participants were African American (63%) and male (95%) with a mean (SD) age of 61.5 (6.7) years and VO2peak of 24.5 (4.9) ml/kg/min. Attendance and adherence to both exercise training interventions were high. The clinically significant increases in VO2peak (ml/kg/min) after HIIT (3.09 ±1.04, p=0.02) and AEX (2.09 ±0.72, p=0.01) represented improvements of 17.1% and 7.7%, respectively. Both groups had improvements in exercise endurance (time on the treadmill) and strength (all p< 0.01). This pilot study supports HIIT as an efficient means to deliver high-intensity AEX to improve cardiorespiratory fitness toward the goal of attenuating the accelerated ageing process in adults with HIV.

Rapid Transition to Telehealth Group Exercise and Functional Assessments in Response to COVID-19.

Exercise is critical for health maintenance in late life. The COVID-19 shelter in place and social distancing orders resulted in wide-scale interruptions of exercise therapies, placing older adults at risk for the consequences of decreased mobilization. The purpose of this paper is to describe rapid transition of the Gerofit facility-based group exercise program to telehealth delivery. This Gerofit-to-Home (GTH) program continued with group-based synchronous exercise classes that ranged from 1 to 24 Veterans per class and 1 to 9 classes offered per week in the different locations. Three hundred and eight of 1149 (27%) Veterans active in the Gerofit facility-based programs made the transition to the telehealth delivered classes. Participants' physical performance testing continued remotely as scheduled with comparisons between most recent facility-based and remote testing suggesting that participants retained physical function. Detailed protocols for remote physical performance testing and sample exercise routines are described. Translation to remote delivery of exercise programs for older adults could mitigate negative health effects.

Short Communication: Low Muscle Mass Is Associated with Osteoporosis in Older Adults Living with HIV.

Sarcopenia, age-related low muscle mass and function, is a well-established independent risk factor for bone fracture in the geriatric population but is understudied in older people living with HIV (PLWH). The objective of this cross-sectional study was to investigate in older PLWH the relationship between muscle mass and bone mineral density (BMD). Sedentary PLWH who were ≥50 years of age, receiving antiretroviral therapy, and enrolled in an exercise intervention trial were included. Established definitions for sarcopenia and osteopenia/osteoporosis were applied to muscle mass data and BMD collected by dual-energy X-ray absorptiometry before exercise training. Participants were 93% male and 33% Caucasian race with median age 61 years, and median CD4 lymphocytes 707 cells/µL. The majority (64%) were overweight and obese by body mass index. Appendicular skeletal muscle index (ASMI) correlated with BMD at the femoral neck (r = 0.49, p < .01), total hip (r = 0.54, p < .01), and lumbar spine (r = 0.48, p < .05). Low BMD at the femoral neck was present in 39% (26% osteopenia, 13% osteoporosis). ASMI was lower among those with low BMD compared with normal BMD (p = .02). Low muscle mass measured by ASMI is associated with low BMD in clinically stable older PLWH. Detailed body composition assessment may help guide lifestyle recommendations to prevent bone fractures in older PLWH.

Association of Diastolic Dysfunction with Reduced Cardiorespiratory Fitness in Adults Living with HIV.

Despite the high prevalence of diastolic dysfunction in adults living with HIV, the impact on cardiorespiratory fitness (CRF) is understudied. The objective of this cross-sectional study was to investigate the relationship between cardiac function and CRF in adults with HIV. Adults receiving antiretroviral therapy with no history of coronary artery disease (CAD) or heart failure were eligible to participate. Cardiac function was assessed by resting Doppler echocardiography. CRF was measured by oxygen utilization at peak exercise (VO2peak). The majority of participants were African American (86%) and male (97%) with a mean [standard deviation (SD)] age of 56.6 (7.1) years and median CD4 lymphocyte count of 492 cells/mL. The mean (SD) VO2peak was 26.1 (5.5) mL/(kg·min). Age, diabetes, hypertension, and hemoglobin were associated with VO2peak. Overall, diastolic dysfunction was present in 38% and was associated with lower VO2peak (p < 0.05). VO2peak was lower among those with impaired myocardial relaxation (e' <8 cm/s) compared with normal relaxation [mean ± SE mL/(kg·min), 25.2 ± 0.6 vs. 27.7 ± 0.9, p < 0.05]. Adjusted for age and clinical factors, each unit increase in left ventricular relaxation (E/A) was associated with an average 4.4 mL/(kg·min) higher VO2peak, representing more than one metabolic equivalent. We conclude that diastolic dysfunction is independently associated with clinically significant low CRF in adults with HIV and no history of CAD or heart failure. These results highlight the importance of recognizing diastolic dysfunction in individuals living with HIV regardless of their cardiovascular disease history.

Providing Rural Veterans With Access to Exercise Through Gerofit.

Clinical video telehealth can be used to deliver functional circuit exercise training to older veterans in remote locations.