Summary: A new study finds that college football players—particularly linemen—are more likely to develop higher blood pressure and changes to left ventricular size and function over a single season.
Source: American College of Cardiology
Linemen show increased blood pressure and left ventricular hypertrophy after one season
College-level American football is associated with a rise in blood pressure and measurable changes in heart size, geometry, and function over a single competitive season, especially among linemen, according to research published in JACC: Cardiovascular Imaging.
The study set out to confirm earlier observations linking football participation with higher blood pressure and enlargement of the heart muscle—commonly referred to as “athlete’s heart”—while focusing on whether those changes might have adverse health implications. The term “athlete’s heart” generally describes the structural and functional adaptations in the hearts of people who perform intense, sustained physical activity.
“Our study confirmed associations between football participation, high blood pressure and cardiac remodeling. Importantly, our findings suggest that heart remodeling in this population may have some maladaptive, potentially pathologic qualities,” said Aaron L. Baggish, M.D., associate director of the Cardiovascular Performance Program at Massachusetts General Hospital and the study’s senior author.
Researchers used data from the Harvard Athlete Initiative, a prospective research program that examines athlete health and exercise physiology. The team enrolled first-year collegiate athletes and followed them through their initial competitive season, a period of roughly 90 days covering preseason and postseason assessments.
Of 190 eligible players enrolled between 2008 and 2014, 87 athletes met the study criteria and were included in the final cohort. Players who missed more than three days of training for any reason or whose echocardiographic images were unsuitable for analysis were excluded. The final sample consisted of 30 linemen and 57 non-linemen (skill and other position players).
Before the season began, 57 percent of linemen and 51 percent of non-linemen met criteria for pre-hypertension. By the end of the season, 90 percent of linemen met the criteria for pre-hypertension or Stage 1 hypertension, while the percentage of non-linemen with elevated blood pressure remained near preseason levels (about 49 percent).
The rise in blood pressure among linemen coincided with measurable thickening of the heart walls and a small but statistically significant decline in contractile function as measured by strain echocardiography. Strain imaging is a sensitive echocardiographic technique that quantifies myocardial deformation and has been shown to predict outcomes across a variety of patient groups.
Importantly, the pattern of cardiac remodeling observed in linemen differed from the classic “athlete’s heart” adaptation seen in endurance athletes. Instead of the eccentric remodeling typical of endurance sports, linemen more often developed concentric left ventricular hypertrophy and reductions in global longitudinal strain—changes that resemble adaptations seen in older adults with hypertension and hypertensive heart disease. In contrast, non-linemen who developed hypertrophy tended to show eccentric geometry with preserved or increased strain.
“While this isn’t the first time we’ve seen that different types of sports participation result in varying forms of cardiac remodeling, this is the first time we’ve identified an athletic population that appears to remodel with maladaptive attributes,” Baggish said. “This type of change to the heart is concerning in this population of young, otherwise healthy athletes and raises questions about long term health implications.”
The study authors note several limitations: potential confounding factors that influence blood pressure (diet, sleep, use of supplements or medications, and other lifestyle variables) were not standardized, and the study length was relatively short compared with many athletes’ multi-year exposure to football. Additionally, a substantial number of originally enrolled players were excluded, which may limit generalizability.
In an accompanying editorial, William A. Zoghbi, M.D., chair of cardiology at Houston Methodist DeBakey Heart and Vascular Center, observed that although many players were excluded, the findings highlight a distinct and potentially adverse cardiac response among linemen. He emphasized the importance of alerting players and clinicians, supporting further research, and exploring preventive strategies to protect the long-term cardiovascular health of athletes in team sports.
This prospective, longitudinal cohort study evaluated NCAA Division I football athletes before and after a single season using transthoracic echocardiography. Athletes were stratified by position: linemen (n = 30) and non-linemen (n = 57). Left ventricular (LV) systolic function was assessed via global longitudinal strain (GLS) using two-dimensional speckle-tracking and by LV ejection fraction (EF) using 2D biplane methods.
Key results included a position-specific increase in systolic blood pressure (mean change in SBP: linemen +10 ± 8 mm Hg versus non-linemen +3 ± 7 mm Hg; p < 0.001) and an increase in incident LV hypertrophy (preseason 8% vs. postseason 25%, p < 0.05). Linemen who developed LV hypertrophy most often had concentric geometry and reduced GLS, while non-linemen with hypertrophy more often had eccentric geometry with increased GLS. Overall EF did not change significantly across the cohort. Independent predictors of reduced GLS after season included lineman position, postseason weight, systolic blood pressure, average LV wall thickness, and relative wall thickness.
Conclusion: Lineman-position participation in American-style football may promote a form of myocardial remodeling that appears pathologic rather than adaptive. Future research should examine whether targeted interventions—blood pressure control, limiting weight gain, and integrating aerobic conditioning—can reduce these adverse changes and improve long-term cardiovascular outcomes for affected athletes.
Original source: Katie Glenn, American College of Cardiology. Study published in JACC: Cardiovascular Imaging (December 5, 2016). DOI: 10.1016/j.jcmg.2016.07.013