Wearing the wrong-sized sports bra could compromise your performance, and studies have shown that up to 80 percent of women make this mistake.
Sports bras are a great way to support your breasts while exercising by limiting excessive breast movement and protecting against discomfort and overstretching of the breast tissue. However, this support can come at the expense of your freedom to fully inflate your lungs.
Newsweek spoke to athlete and Mayo Clinic research fellow Shalaya Kipp about how the wrong-sized sports bra can affect breathing and respiratory function and how to make sure you are choosing the right size.
"Respiratory function may become compromised by the pressure exerted by the underband of a sports bra when women self-select their bra size," Kipp told Newsweek.
To investigate these effects, Kipp and colleagues from the University of British Columbia recruited nine highly-trained female runners and measured their breathing capacity and efficiency while wearing sports bras with different levels of tightness. The results of the study, which was funded by sportswear brand Lululemon, were published in the journal Medicine and Science in Sports and Exercise.
"In our study, loosening the sports bra underband changed how women breathed," Kipp said. "They took deeper, less frequent breaths...and improved running economy."
But how do these findings equate to actual running performance?
When the women in the study wore the underband at its tightest setting, the researchers saw a 1 to 2 percent increase in their oxygen consumption. If loosening the band was met with a 2 percent increase in oxygen efficiency, this could have significant effects when running over longer distances.
"For an individual running a 3-hour marathon, a 2 percent improvement in oxygen consumption equates to a 3-minute improvement," Kipp said.
"Our results definitely underscore that bra restriction can have whole-body effects and may impact performance."
Of course, these findings were drawn from a very small group of highly trained women and thus do not encapsulate the broad diversity of women's bodies.
"Breast size is an important factor that potentially affects how apparel interacts with respiratory mechanics," Kipp said. "There is so much more research that needs to be done in this area."
The study emphasizes the importance of finding a correct-fitting sports bra.
"Most women pick their sports bras based on how they feel at rest," Kipp said. "However, it was only during hard exercise—when the women in our study were breathing hard and inflating their lungs—that respiratory function was compromised. So, it probably makes sense for women to evaluate their sports bras based on how they feel at the end of a workout rather than how they feel in the dressing room of a store.
"I've suggested to some women to try to take large breaths next time they're in a dressing room trying on bras.
"Additionally, women can try going up a size in their sports bra and see if the breast motion/displacement is still comfortable. This won't work for everyone, but if some women are self-selecting a bra that is too tight, going up a size might help and they may find the loose underband still provides enough support during exercise."
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Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
About the writer
Pandora Dewan is a Senior Science Reporter at Newsweek based in London, UK. Her focus is reporting on science, health ... Read more
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