The median age of Americans diagnosed with heart failure is 77 years old. With 5.7 million individuals suffering from heart failure, it is the leading cause of hospitalization for individuals 65 years and older.
The recommended treatment for these individuals, whose symptoms include fatigue and shortness of breath, is a relatively standard exercise routine: moderate-intensity aerobic exercise paired with resistance training. However, according to Jason Allen, professor of Kinesiology at the University of Virginia School of Education and Human Development, those recommendations come from data that was collected from much younger individuals, some as young as 51.
“For a long time, exercise has been suggested as a one-size-fits-all solution,” Allen said. “But we know that prescribing the same exercise protocol to a 75-year-old patient with heart failure, who likely will have several comorbidities and reduced muscle mass, as we would to a healthy 50-year-old may not be the most effective approach.”
With promising findings from a pilot study and a new $3M grant from the National Institutes of Health, Allen and colleagues from across UVA is expanding a novel approach he has named “PRIME” - Peripheral Remodeling via Intermitted Muscular Exercise. PRIME is focused on exercising peripheral muscle tissues without imposing a large central strain on the heart.
With this funding, Allen and colleagues will enroll 92 patients into the study and compare patients who start exercise using PRIME for 4 weeks followed by traditional training for 8 weeks versus those who participate in the standard recommended exercise treatments for the whole 12 weeks. Allen will be joined on this project by Kinesiology colleagues Art Weltman, professor, and Siddhartha Angadi, assistant professor; Drs. James Bergin, Mohammad Abuannadi and Stephane Phillips, from UVA’s division of cardiovascular medicine; and James Patrie, senior biostatistician.
“Imagine you are pumping water to your garden, but the pump is not working at full capacity,” Allen explained. “A standard exercise protocol is like watering the whole yard at once which puts a lot of stress on the pump (heart) and doesn’t distribute enough water to soak the garden anywhere. PRIME is like only turning on water to a small area at any one time, to maximize flow there, then moving to the next section.”
Patients utilizing the PRIME exercise protocol do resistance training focused on specific muscle groups, but in a way that stresses the muscles at about 50% of their maximum strength over a period of 5 minutes. “Then we move on to the next exercise/muscle group,” Allen said.
The heart can cope with smaller groups of working muscles, so they receive an adequate blood supply. This allows them to work harder, become more efficient, and even reverse some dysfunctions.
“Eventually the muscles get stronger but also more efficient so the patient can start to do more whole-body activities,” Allen said.
In the pilot study, Allen and colleagues in Australia, found that older heart failure participants increased their walking capacity more after four weeks of PRIME than participants who spent that time walking on a treadmill. When everyone added whole body exercise for the next four weeks those who started with PRIME continued to do better.
PRIME is an example of how exercise science is moving from “one size fits all” to more precise interventions for specific populations.
“The hope is that we are setting up different ways to deliver exercise prescriptions tailored specifically to different clinical populations that maximize the benefit for those individuals,” Allen said.