Performance on a treadmill stress test, used to calculate your “physiological” age, is a better predictor of longevity than your actual chronological age.
And when doctors talk about physiological age – whether their bodies are older or younger than the actual years they have lived – patients are more motivated to maintain their exercise regime or improve it.
This is because they are given a simpler picture – rather than a more complex detailing of health factors measured in testing – and can more easily understand how their level of fitness is keeping them “younger” or pushing them into the grave.
Data from 25-year study
These are the conclusions of a massive study of 126,356 patients over a 25-year period published this week in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).
“Age is one of the most reliable risk factors for death: the older you are, the greater your risk of dying,” said study author Dr Serge Harb, cardiologist at the Cleveland Clinic in the United States, in a prepared statement.
“But we found that physiological health is an even better predictor. If you want to live longer, then exercise more. It should improve your health and your length of life.”
To determine a patient’s physiological age, the researchers developed a formula to calculate how well people exercise that they call A-BEST (Age Based on Exercise Stress Testing). The equation uses exercise capacity, how the heart responds to exercise (known as chronotropic competence), and how the heart rate recovers after exercise.
“Knowing your physiological age is good motivation to increase your exercise performance, which could translate into improved survival,” said Dr Harb.
A more effective wake-up call
“Telling a 45-year-old that their physiological age is 55 should be a wake-up call that they are losing years of life by being unfit. On the other hand, a 65-year-old with an A-BEST of 50 is likely to live longer than their peers.”
The study was a simple one. It looked at 126,356 patients referred to the Cleveland Clinic between 1991 and 2015 for their first exercise stress test – a common examination usually prompted by an abnormal ECG (electrocardiogram) and for otherwise diagnosing heart problems.
The test involves being wired up to an ECG and walking on a treadmill, which gets progressively faster and the incline steeper. During the test, exercise capacity, heart rate response to exercise, blood pressure, heart rhythm and heart rate recovery are all measured. The data were used to calculate A-BEST, taking into account gender and use of medications that affect heart rate.
The average age of study participants was 53.5 years and 59 per cent were men. More than half of patients aged 50 to 60 years were physiologically younger, according to A-BEST.
After an average follow-up of 8.7 years, 9929 participants had died.
A-BEST was found to be “a significantly better predictor of survival than chronological age, even after adjusting for sex, smoking, body mass index, statin use, diabetes, hypertension, coronary artery disease, and end-stage kidney disease”, according to a statement from the European Society of Cardiology.
Will your GP take up the new approach?
The question now is whether or not the A-BEST formula will be taken up as a new way for doctors to report results of exercise stress testing to patients. Dr Harb is touting the benefits.
“Telling patients their estimated age based on exercise performance is a powerful estimate of longevity … and easier to understand than providing results for the individual components of the examination.”
He added that this type of approach has shown merit in specific disease areas, pointing to European Society of Cardiology guidelines that advocate using “cardiovascular risk age” – based on risk factors including smoking, blood cholesterol and blood pressure – to communicate with patients.
The big take-away is an obvious one. Exercise keeps you not only feeling young, but actually takes a few years wear off the body.
A 2007 study from the University of South Carolina examined the links between fitness, fatness and mortality in older adults, and found that being fit after the age of 60 helps you live longer, regardless of your body’s fat content.