People cite a variety of well-known reasons for not exercising regularly, including lack of time, lack of motivation, family commitments, injuries and illness.
Many women stay sedentary, however, for a reason that’s received much less attention (although it’s talk about a lot among women): breast discomfort.
Surprisingly little research has been done on this topic. Among the few studies is a 2015 survey of 249 British women. It found that breast-related issues were the fourth greatest barrier to physical activity for women, behind lack of energy and motivation, time constraints and health.
In a new study, published this month in the Journal of Science and Medicine in Sport, researchers have examined the topic more closely. They found that breast discomfort — the pain caused by excessive movement of the breast while exercising — has a significant effect on the amount and type of exercise that women do.
Specifically, the study found that women with large breasts spend almost 40 percent less time exercising than women with smaller breasts.
For the study, researchers at the Biomechanics Research Laboratory at the University of Wollongong in Australia recruited 355 healthy women. The volunteers ranged in age from 18 to 75 and in body mass from normal through obese.
The women filled out a questionnaire about their physical activity during the previous week. It included questions about the types of activity they did (such as walking, biking, swimming, dancing and gardening), as well as how long and how intensely they did them.
The women were also asked if their breast size had ever influenced the amount or level of physical activity they had done and, if so, what types of activities had been affected.
Then, using a handheld three-dimensional scanner, the volume of each woman’s breasts was measured and categorized as either small, medium, large or hypertrophic (very large).
The researchers then looked for any correlations between breast size and exercise habits.
The findings were striking, but perhaps not surprising to many women. The larger the women’s breasts, the less time they spent exercising, particularly doing vigorous activities that involve excessive “bouncing,” such as running, aerobic classes and dancing.
The time difference was quite significant. Women with very large breasts spent, on average, 37 percent less total time exercising than those with small breasts.
That finding held even after the researchers controlled for age and body mass index (BMI) — two factors that can affect how often and vigorously people exercise.
The women with larger breasts were also much more likely to report that their breast size kept them from being more physically active, even with less vigorous activities, such as walking and swimming. (Interestingly, many of the women with large breasts in the study said they didn’t swim because they couldn’t find comfortable swimsuits.)
Limitations and implications
The study has several limitations. It involved a relatively small number of participants, and all the information about exercise was self-reported. In addition, more than a quarter of the study’s participants were between the ages of 18 to 24, a group that tends to be more physically active than older women.
Still, the findings offer compelling evidence of the significant effect that breast size can have on women’s exercise habits — and on their health.
“Breast size should be acknowledged as a potential barrier to women participating in physical activity,” the study’s authors write.
Women need more help with finding well-fitting sports bras and with developing strategies that will enable them to participate in all types and intensities of physical activity, no matter what their breast size, the researchers conclude.
FMI: The researchers have developed a website with information about exercise and breast support and tips about buying a sports bra. You’ll find an abstract of the study on the Journal of Science and Medicine in Sports website.