March 26, 2015
How to Determine Life Expectancy in the Next Decade
A new report from the Johns Hopkins Cardiology Center estimates that one's risk of dying over the next ten years is based on a person's ability to exercise on a treadmill at an increasing speed and incline.
Johns Hopkins cardiologists analyzed data from 58,000 heart stress tests and developed a formula that estimates one's risk of dying over the next decade.
The new formula dubbed "FIT Treadmill Score" gauges long-term death risk in anyone based solely on treadmill exercise performance. The score can yield valuable clues about a person's health.
The formula factors in peak heart rate reached during intense exercise and the ability to tolerate physical exertion as measured by metabolic equivalents, a gauge of how much energy the body expends during exercise.
“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, M.D., M.P.H., director of clinical research at the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease.
For the study, the team analyzed information on 58,020 people, ages 18 to 96, from Detroit, Michigan, who underwent standard exercise stress tests between 1991 and 2009 for evaluation of chest pain, shortness of breath, fainting or dizziness. The researchers then tracked how many of the participants within each fitness level died from any cause over the next decade. 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 — a finding that underscores the profound importance of heart and lung fitness, the investigators say.
Scores ranged from negative 200 to positive 200, with those above 0 having lower mortality risk and those in the negative range facing highest risk of dying. Patients who scored 100 or higher had a 2 percent risk of dying over the next 10 years, while those with scores between 0 and 100 faced a 3 percent death risk over the next decade. In other words, two of 100 people of the same age and gender with a score of 100 or higher would die over the next decade, compared with three out of 100 for those with a fitness score between 0 and 100. People with scores between negative 100 and 0 had an 11 percent risk of dying in the next 10 years, while those with scores lower than negative 100 had a 38 percent risk of dying.