In a study of more than 1,100 male firefighters followed for 10 years, researchers found that the risk of atherosclerosis and of cardiovascular events, such as stroke and heart attack, was 96 percent lower among men who could do 40 or more push-ups during timed tests compared to the men who could do fewer than 10.
The findings could lead to an easy test for heart disease risk, said the study’s lead author Dr. Justin Yang, a researcher at Harvard’s T. H. Chan School of Public Health in Boston.
“Using push-ups could be a no-cost and simple method to assess one’s functional capacity and predict future cardiovascular event risk,” Yang said. “For clinicians, this is really important since a lot of tests vary in their results and are very expensive and time-consuming. This can be done within a minute.”
To look at possible predictors of heart disease, Yang and his colleagues turned to data on 1,104 Indiana firefighters who had health exams between February 2, 2000, and November 12, 2007. Along with push-up capacity, a host of other measurements were recorded at the same time, including age, VO2 max (the maximum rate of oxygen consumed during intense exercise), height, weight, resting heart rate, blood pressure levels, cholesterol levels, blood sugar levels, and smoking status.
At baseline, the firefighters’ average age was 39.6 years and their average body mass index (BMI, a ratio of weight to height) was 28.7, which is in the “overweight” range. “With firefighters pictured on calendars as muscular and very fit, we tend to think of them as different from everyone else, but this group is pretty much the same as the rest of the population,” Yang said. “Half of them were overweight or obese.”
During the study period, there were 37 cardiovascular disease-related outcomes among the men, according to the report in JAMA Network Open.
While other factors, such as age, BMI and VO2 were also predictive of the risk for cardiovascular disease events, push-ups were the strongest indicator, Yang said.
One strength of the new study is that it relies on a measure of strength rather than on self-reports of physical activity, said Kerry Stewart, a professor of medicine and director of clinical and research exercise physiology at the Johns Hopkins School of Medicine in Baltimore, Maryland.
Stewart suspects that the men’s push-up capacity is simply a marker for their level of fitness. “You have to be pretty fit to do that many push-ups,” said Stewart who was not involved in the new research. “You would probably have to do a good amount of exercise on a regular basis to get to the level of 40 or more.”
And fitness, Stewart said, is correlated with a number of factors, including blood pressure, cholesterol levels, and abdominal fat. The findings underscore the importance of guidelines that emphasize both resistance training and aerobic exercise, Stewart noted.
Dr. Dennis Bruemmer wasn’t surprised by the findings. “We have long known that physical inactivity constitutes a risk factor for cardiovascular disease and is associated with worse outcomes,” said Bruemmer, an associate professor of medicine and a cardiologist at the Heart and Vascular Institute at the University of Pittsburgh Medical Center in Pennsylvania. “Conversely, physical activity decreases cardiovascular risk.”
The new research underscores the importance of following the current American Heart Association guidelines, which recommend at least 150 minutes of moderate-intensity aerobic exercise per week, said Bruemmer, who was not involved with the new study. Such exercise, “could be easily be integrated into the workplace environment and should be part of a work-life balance, Bruemmer said in an email.