Walking at a turtle’s pace may be a bad omen for your upcoming heart surgery, a new study published Wednesday in the Journal of the American Medical Association finds.

The researchers pooled together three years worth of data from 15,171 patients over the age of 60 who went under the knife. Prior to their procedure, the patients were asked to walk a distance of 5 meters, or about 16 feet, as comfortably and quickly as they could, repeating the course twice over. In total, 314 patients died in the first thirty days following surgery. Of these, those who were in the slowest third, walking less than 0.83 meters per second, were about three times more likely to die than those who were among the fastest third. After adjusting for other variables, including the type of surgery the subjects were given, the study found that for each decrease of 0.1 meters per second in walking speed there was a relative 11 percent increased risk of death. A similar link was seen for other complications, such as needing surgery again.

“Gait speed is … a useful screening test for frailty in older adults being considered for cardiac surgery,” the authors wrote.

In the medical world, frailty is a useful but somewhat vague concept for determining a person’s future health, especially among the elderly. Though it might seem easy to tell if someone is frail, the various measures doctors use, including walking speed, unintentional weight loss, and low physical activity, often don’t align with one another perfectly. We do know frailty is more likely, but not certain, the older we get, and that it helps speed us along to an earlier grave, especially following surgery. Understanding the specifics of that link would allow for better patient care.

“Prediction of operative risk, particularly in the complex clinical case of a patient with multiple chronic conditions, can help the care team and patient arrive at the most informed decision aligned with values and goals for both survival and quality of life,” the researchers wrote.

Though earlier research has shown that walking speed alone could be a reliable guide of mortality risk, the study authors wanted to reexamine the possible connection using a wider sample size and a much shorter time window than previous efforts. And sure enough, their numbers line up with a large review of nine studies that found a 10 percent decreased risk of death for every 0.1 meter per second increase in speed — these studies, however, looked at elderly people in the outside world over a five-year period.

The current findings, while clinically significant overall, only offered a slight nudge in predicting who would be worse off following surgery. This might be because the study looked at relatively healthy people; the authors noted that other studies of frailty in higher-risk patients have found a more substantial connection to post-surgery outcomes.

The researchers now hope that additional research can look into how walking speed predicts other long-term health risks, and they advocate further randomized trials that can establish the usefulness of interventions like exercise training and nutritional supplementation prior to surgery in improving the frailty — and outlook — of elderly patients. In that latter spirit, there is currently a study being run out of the St. Boniface General Hospital Research Center in Winnipeg, Canada that is recruiting frail patients about to undergo heart surgery to either receive standard care or go through an eight-week exercise and educational program. The study is estimated to conclude May 2017.

Source: Afilalo J, Kim S, O’Brien S, et al. Gait Speed and Operative Mortality in Older Adults Following Cardiac Surgery. JAMA. 2016.