New study can help determine optimal exercise for cardiovascular diseases

Researchers at the University of Gueph tested the hearts of 16 elite runners and 16 elite swimmers to determine how their hearts adapt and recover after exercise. 

According to lead researcher and professor Jamie Burr, the study was meant to be an inquiry into determining if there are optimal ways to prescribe exercise for different cardiovascular diseases.

Burr says this study is just the "first step" and a "stepping off point" for figuring that out.

His team at the university's human performance and health research lab found that during the heart's resting period, called diastole, runners' hearts can restore blood quicker than those of swimmers. 

"It's actually more like wringing out a dish cloth. It twists itself as it contracts and when it relaxes, it untwists," Burr said, describing how the heart functions. 

"When it untwists, it creates a little bit of a suction so blood gets pulled back into the heart and that's the part we think is a little bit different — a runner's heart untwists a little bit quicker and it sucks in a little bit more blood, getting ready for the next heartbeat faster because it's working against gravity," he said. 

An 'optimal way for different cardiovascular diseases' 

Paul Oh, medical director of the cardiovascular prevention and rehabilitation program at the Peter Munk Cardiac Centre and University Health Network in Toronto, says this study might help doctors and researchers understand how patients with different blood volume cope and respond to exercise. 

For years, doctors have been prescribing cancer and cardiovascular patients with exercise, which overall prevents heart attacks, strokes and sudden death.  

"It makes it much more specific, smart, measurable, actionable on the part of the patient," said Oh.  

"Some patients might have challenges in coping with the greater fluid or blood volume that's in the middle. If you've had some impairment in the heart, then we tend not to recommend swimming as the right modality but rather upright activities might be preferred," he said. 

"This study does help us understand that to some degree, in terms of those kinds of differences, where blood volumes goes and how the heart adapts to that."

However, both Burr and Oh noted that the group of people tested in this study are elite athletes, who already have excellent cardiovascular function. 

Burr also reaffirms that all exercise is generally beneficial for all individuals, but he hopes the research can help people further understand how hearts adapt with different physical activities. 

"If we can make the heart adapt in a different way, maybe there's an optimal way for different cardiovascular diseases," he said.  

"So if you have a condition where you have a volume overload, which represents swimming, where getting blood back to the heart is not a problem, maybe you would want to train the heart a little different," Burr said.