It might not be obvious to those who spend Saturdays cheering on their alma mater on the gridiron, but playing college football is linked to changes that negatively affect the heart.
However, not all players are affected equally — position makes a difference, a new study finds.
In the research, linemen were more likely to develop high blood pressure over the course of a season than players in other positions were, according to the study, published Dec. 5 in the journal JACC: Cardiovascular Imaging.
Linemen tend to be bigger than other players on the field, as their primary job is to block and tackle . Indeed, the linemen in the study had, on average, higher BMIs than players in other positions, such as quarterbacks and wide receivers.
Previous research has shown that former professional linemen have an increased risk of dying from heart disease, but scientists weren't sure what caused this increased risk, the new study said.
This research included 87 freshmen athletes who played on the Harvard University varsity football team between 2008 and 2014. Before each football season began, the researchers measured the athletes' blood pressure and took images of their hearts, according to the study. The same measurements were taken after the season ended.
The researchers looked to see which players had "prehypertension," meaning that their blood pressure fell between what's considered "normal" (120/80 mm Hg) and what's considered hypertension (140/90 mm Hg).
Results showed that before the season began, the rates of prehypertension were similar between linemen and nonlinemen: 57 percent of the linemen had prehypertension, and 51 percent of the nonlinemen had the condition, the researchers wrote.
But at the end of the season, 60 percent of the linemen had prehypertension and another 30 percent had hypertension, while in the nonlinemen, the rates remained the same as in the preseason, the researchers found.
In addition, at the end of the season, cardiac imaging showed changes to the structures of the linemen's hearts that were "concerning in this population of young, otherwise healthy athletes and" that raise "questions about long-term health implications," Dr. Aaron Baggish, the associate director of the Cardiovascular Performance Program at Massachusetts General Hospital and the senior author of the study, said in a statement.
More research is needed on how sports may affect athletes' hearts , Dr. William Zoghbi, the chairman of the cardiology department at Houston Methodist DeBakey Heart and Vascular Center, said an editorial accompanying the new findings. Zoghbi was not involved in the study.
Originally published on Live Science.