Push-ups may be a good proxy for physical fitness that is associated with better long-term cardiovascular health, according to a study of male firefighters.
The more push-ups these emergency responders could do, the lower their risk of cardiovascular disease (CVD) events over the next 10 years, with a 15% cumulative incidence among those who could do up to 10 compared with 5% or lower among those who could complete more, Stefanos Kales, MD, MPH, of Harvard Medical School, and colleagues found in the longitudinal cohort.
Firefighters who could do more than 40 push-ups had much lower 10-year risk than those who couldn’t complete more than 10 (incidence rate ratio 0.04, 95% CI 0.01-0.36), as did those who could do 21-30 push-ups (HR 0.25, 95% CI 0.08-0.76).
The message was twofold — for patients and for the clinic, Kales’ group wrote in the Feb. 15 issue of JAMA Network Open:
“Based on the current study, CVD risk factor reduction should be recommended, including lifestyle measures for those with low push-up capacity, especially those capable of ten or fewer push-ups,” they concluded. “Although larger studies in more diverse cohorts are needed, push-up capacity may be a simple, no-cost measure to estimate functional status.
The current gold standard of cardiorespiratory fitness is the cardiopulmonary stress test, and it is recommended that poor performers receive cardiovascular risk reduction management. “However, this test is expensive, time consuming, and requires special equipment,” said John Higgins, MD, of McGovern Medical School at The University of Texas Health Science Center at Houston, who was not involved with the study.
Overall, the new findings are “another piece in the puzzle of fitness and survival showing that any type of fitness (aerobic or anaerobic, isotonic or isometric) is associated with survival benefits,” commented Wael Jaber, MD, of the Cleveland Clinic, who was also not in Kales’ group.
“In a novel way, resistance fitness rather than aerobic fitness (treadmill) is shown to be inversely associated with all mortality,” Jaber told MedPage Today.
The 1,104 firefighters included in the study ranged in age from 21-66 years (mean 39.6) and were all men. All had received periodic physical examinations at one Indiana outpatient clinic and had push-up information available. The average BMI was 28.7.
Investigators noted that their results may have limited generalizability to other groups such as women and that the analysis was not adjusted for multiple comparisons.
Additionally, it is questionable if the study authors could fully adjust for BMI for an activity that not only measures arm strength but how much weight has to be pushed up, cautioned Paul Thompson, MD, of Hartford Hospital in Connecticut, in an interview.
And given that push-ups were required to be done quickly among the firefighters (in time with a metronome set at 80 beats per minute), Thompson said he was “not totally certain that they eliminated the component of aerobic fitness” in the push-up assessment, adding that aerobic capacity was not very well assessed.
Even so, the take-home message is that being in good shape is associated with better outcomes, Thompson said. He cited hand grip and standing up without using hands as other physical tasks that have been associated with survival.
“Maybe you should have people do push-ups to get a sense of longevity,” he said. “I don’t have a great problem with that.”
Although clinicians aren’t likely to ask their patients to drop down and do push-ups anytime soon, he said that the activity may be more frequently used to test groups like firefighters.
“I think also, one can be unhealthy, then get healthy and start working out, and reduce one’s cardiovascular risk factors (better blood pressure, cholesterol, insulin levels, weight) – so it makes sense that push-ups, which reflect resistance training and fitness, are a good marker of cardiovascular risk,” Higgins noted.
Kales reported serving as an expert witness in firefighter cases; and receiving personal fees from Bichler, Kelley, Oliver & Longo; McCarthy, Callas & Feeney, PC; Macadam, Jury, PA; Sena, Polk & Stacy; and Lichten & Liss-Riordan, PC.
Jaber and Thompson listed no conflicts of interest.