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A simple stretch could help prevent future events for people with cardiovascular disease 

To stretch or not to stretch before a workout. It’s a question that exercise circles have debated for decades.  

A UW-La Crosse study shows some new promise for the importance of stretch — especially for those with cardiovascular disease. 

While exercise is good for us, studies have shown that a workout can cause a temporary and slight reduction in the function of our blood vessels — a network of tubes that carry blood throughout the body. When blood vessels aren’t functioning at full capacity, it puts people with cardiovascular disease at risk of having a heart attack, stroke or other vascular event. 

Is stretching good or bad?

A recent UWL study found that passive stretching before a workout can allow your blood vessels to be more resilient to the stress of exercise. Passive stretching is when an external force such as a towel or boot allows you to stretch a muscle instead of using your own muscular strength to hold a stretch. In the study, both large and small blood vessels functioned better when passive stretching was performed than when it wasn’t.  

In the study, one group of participants passively stretched their calf muscles during four, five-minute cycles before exercise. Another group did no stretching. The group that did not stretch had a 50 percent decline in blood vessel function while the stretching group had a 25 percent decline in function. While both groups saw a decline, the stretching group did a much better job of retaining blood vessel function, explains Jacob Caldwell, lead-author of the study and UWL assistant professor of Exercise and Sport Science. The research is published online in the Journal of Applied Physiology. 

The study was performed using healthy, college-aged student participants. The next phase of the research could test whether the same results are found with a clinical population such as those who have had a previous heart attack, stroke or peripheral artery disease, notes Caldwell. 

The study shows promise for patients who have had a vascular event and want to continue to improve their health and daily living through exercise. 

A 'full circle’ experience 

UWL student Sarah Fenn became interested in Caldwell’s research after being a subject in his passive stretch study her junior year at UWL.  

“It was such new and uncharted territory to see what research was all about,” she says. “They were collaborating in the lab, collecting data and answering these important questions. I was like, ‘I want to do that too.’”  

Fenn asked to join the lab, and, since then, she’s gained a host of skills and solidified her passion for research. She was recently offered a full-ride scholarship in the doctoral program at the Medical College of Wisconsin, as well as another generous offer from another institution. Fenn plans to take a year off to travel in Spain before beginning a doctor of physical therapy degree program and then continue on for a doctoral degree in rehabilitation science to allow her to continue to do research.  

She said UWL research gave her a “full circle experience” doing a range of research tasks: scheduling research subjects, performing lab techniques and analyzing data.  When she earned a travel grant in spring 2023 to present her research at the American Physiology Summit in California, the award pushed her mentor, Caldwell, to extend his research and explore a new path in cardiovascular research. 

“Without students and their driving force, it’s impossible to do what we do,” he says.  “Good students help in the lab. Great students move labs forward and Sarah is a great student.” 

The new branch of research explored how passive stretching compares to a more traditionally-used method for improving blood vessel function prior to a workout. That method is called Ischemic preconditioning, or non-lethally cutting off blood flow to a part of the body and then releasing it. Their research found that the two methods are similar in terms of improving blood vessel function. Fenn presented this research at the American Physiology Summit.  

“Seeing her change over the year and half we’ve been working together has been very enlightening,” says Caldwell. “Outside of family, it’s one of the most rewarding things to see your students grow as a professor and to be excited for their future. Regardless of where she goes, she is going to do amazing things. To know I helped alter her trajectory in positive way, it is why I do it.”