Exploring the effects of exercise training on people with atrial fibrillation

Atrial fibrillation is an abnormal heart rhythm which leads to a rapid and irregular heartbeat, making it difficult to get enough blood and oxygen moving around the body to support everyday activities. 

It’s the most common abnormal heart rhythm in Australia and across the globe, and almost half (up to 47 per cent) of people who have the condition suffer from a reduced ability to perform strenuous physical exertion – a symptom known as exercise intolerance.    

Through an Alfred Deakin Postdoctoral Research Fellowship, Dr Kim Way is exploring if there are small blood vessel complications in the muscle that might explain exercise intolerance in people living with atrial fibrillation.  

Previous research has focused on changes to the structure and function of the heart, but little attention has been given to the possible impacts of this condition on the other large and small blood vessels in the body.  

“Our smallest blood vessels are the most important blood vessels that deliver the nutrients and oxygen we need to create energy for all of our activities and bodily functions,” Dr Way said.  

“Many people with atrial fibrillation are exercise intolerant, which means they find usual activities such as going up a flight of stairs difficult, as they become fatigued and short of breath.” 

Dr Way believes a key part of this exercise intolerance is impaired blood flow in the small blood vessels, particularly skeletal muscle.  She is using a highly specialised contrast enhanced ultrasound technique to examine the blood flow to the muscle before and following exercise in adults with and without atrial fibrillation.  

Dr Way is also running a randomised controlled trial in people with atrial fibrillation to examine the effects of exercise training on the small blood vessels. Participants will either be given a combined exercise training program with aerobic and resistance exercises, or a ‘mock’ exercise program involving light stretches that won’t raise the heart rate too high. 

She will then take various measures before and after the intervention to see if exercise training is a viable method to improve small blood vessel health in this group.  

“At present, treatment for atrial fibrillation is predominately centred around pharmaceutical and surgical interventions to help control the condition and manage complications,” Dr Way explained. 

“Exercise training could be considered like a magic pill – it impacts so many bodily systems that not only will it likely improve the small blood vessel health in people with atrial fibrillation, but we know it can also help slow down heart rate and improve cardiovascular risk factors – therefore, directly slowing the progression of the condition.”    

 Dr Way hopes her study will reinforce the need for guidelines to include exercise as part of usual patient care for people with atrial fibrillation.