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New ‘treadmill test’ can predict mortality

Test could be used as wake-up call for the inactive

Jo Carlowe

Monday, 02 March 2015

US scientists have developed a formula for estimating a person’s risk of dying over a decade base on their ability to exercise on a treadmill.

Although several exercise-based risk scoring systems are already in use that are designed to measure short-term risk of dying, they are limited to patients with established heart disease or overt signs of cardiovascular trouble.

Analysing data from 58,000 heart stress tests, Johns Hopkins cardiologists have developed a new algorithm, dubbed the FIT Treadmill Score and described in today’s issue of the journal Mayo Clinic Proceedings

In addition to age and gender, the formula factors in peak heart rate reached during intense exercise and the ability to tolerate physical exertion as measured by so-called metabolic equivalents, or METs, a gauge of how much energy the body expends during exercise.

The results reveal that among people of the same age and gender, fitness level as measured by METs and peak heart rate reached during exercise were the greatest indicators of death risk. Fitness level was the single most powerful predictor of death and survival, even after researchers accounted for other important variables such as diabetes and family history of premature death

The new system can gauge long-term death risk in anyone based solely on treadmill exercise performance. The score, the research team says, could yield valuable clues about a person's health.

“The notion that being in good physical shape portends lower death risk is by no means new, but we wanted to quantify that risk precisely by age, gender and fitness level, and do so with an elegantly simple equation that requires no additional fancy testing beyond the standard stress test," says lead investigator Haitham Ahmed, a cardiology fellow at the Johns Hopkins University School of Medicine.

"The FIT Treadmill Score is easy to calculate and costs nothing beyond the cost of the treadmill test itself," says senior study author Michael Blaha, director of clinical research at the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease. 

"We hope the score will become a mainstay in cardiologists and primary clinicians' offices as a meaningful way to illustrate risk among those who undergo cardiac stress testing and propel people with poor results to become more physically active.”

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