Improving outcomes from cardiac rehabilitation among older adults through exercise testing and individualized exercise intensity prescriptions - PROJECT SUMMARY Heart disease and its treatments, including hospitalization, surgery, and procedures, can result in devastating loss of function, particularly in inactive older adults, who often face a prolonged recovery. Maximizing fitness and promoting adequate physical activity (PA) are critical targets for healthy aging and recovery after a cardiac event. Cardiac rehabilitation (CR) provides up to 36 supervised exercise training sessions and lifestyle counseling to these patients and is thus ideally positioned to promote full recovery, encourage regular PA, optimize cardiac health, and support more successful aging for these patients. However, many CR programs fail to meet established benchmarks for improving fitness among their patients. This failure is likely attributable to marked differences in exercise intensity prescription practices across CR programs, which have recently been identified. Specifically, the most common method for prescribing exercise intensity in CR is the use of ratings of perceived exertion (RPE) coupled with a “rule of thumb” approach to achieve an exercise training heart rate (HR) that is 20-30 bpm higher than resting HR. While easy to implement, these usual care (UC) techniques often result in a self-selected and suboptimal exercise intensity. This, in turn, leads to lower gains in fitness and failure to reach established benchmarks. Instead, societal guidelines recommend patients undergo a graded exercise test (GXT) to measure a peak exercise HR and be prescribed exercise intensity using a computed target heart rate range (THRR). This approach (GXT-THRR) allows tailoring of exercise based on the individual patient’s response to acute exercise. However, no studies to date have tested the efficacy of GXT- THRR compared to UC, and this critical knowledge gap is likely responsible for the marked differences in exercise intensity prescription techniques across programs. Our preliminary data suggest GXT-THRR will lead to greater gains in fitness in CR, boost self-efficacy, reduce fear of exercise, and improve outcomes. To address this fundamental question, we will perform a 320-person randomized trial comparing GXT- THRR to UC among older adults with heart disease attending CR. In Aim 1, we will measure improvements in fitness during CR. In Aim 2, we will assess the impact of GXT-THRR on psychological factors associated with exercise adherence (self-efficacy and fear). In Aim 3, we will evaluate how the use of GXT-THRR impacts long-term PA, quality of life, fitness, and clinical outcomes. Our multi-disciplinary team has broad experience in all aspects of this proposal, including exercise physiology, CR, cardiology, geriatrics, and psychology. Our approach is informed by a successful pilot trial which demonstrated the clear feasibility and potential effectiveness of GXT-THRR. Ultimately, we anticipate our results will promote evidence-based exercise intensity practices in CR programs, leading to greater improvements in fitness, PA, and exercise self-efficacy, and more successful aging.
