Hop on your nearest
treadmill and get running with this simple death test. (Photo: Getty Images)
Want to make sure you’ll
be around in 10 years? Hop on a treadmill: After analyzing 58,000 stress tests,
Johns Hopkins researchers determined — with great accuracy — that the results
of a treadmill test could predict risk of death over a decade.
In the study — while being
watched by professionals — people who were heart disease-free, but referred for
an exercise stress test completed a treadmill test called the Bruce Protocol.
And while this wasn’t
tested in a general population, the Bruce Protocol formula is valid:
“We could assume that in
people with no symptoms, this treadmill test would at least predict the level
of survival over a decade,” Haitham Ahmed, MD, MPH, and lead author of the
study tells Yahoo! Health.
Calculating your own
score.
So how exactly is it done?
The test consists of three-minute segments
that increase in speed and incline.
In the study, people
exercised until they were fatigued, felt chest discomfort, or until a clinician
saw something suggesting lack of blood flow to the heart, says Ahmed.
Stage
1 1.7 mph/10% grade/5 METs
Stage 2 2.5 mph/12% grade/7 METs
Stage 3 3.4 mph/14% grade/10 METs
Stage 4 4.2 mph/16% grade/13 METs
Stage 5 5.0 mph/18% grade/15 METs
Stage 6 5.5 mph/20% grade/18 METs
Stage 7 5.5 mph/22% grade/20 METs
In addition to accounting
for age and sex, the formula used in the study factored in how well you tolerate
exercise — measured in “metabolic equivalents” or METs, says Ahmed.
This tells you how much
energy you’re expending while working out. (More vigorous exercise means higher
METs.)
“The longer you can stay
on, the more METs you accrue,” he says, noting that the median MET score was
10.
“More than 10 METs was
associated with a higher fitness level and good survival rate.”
Then,
researchers used the following formula:
(12 x METs)
+ (% of maximum predicted heart rate) – (4 x age) + 43 if female.
*Maximum
predicted heart rate is calculated as 220 – age. Heart rate achieved during
exercise should be divided by maximum predicted.
For example, if you’re 20 years old, your
maximum predicted heart rate is 200 (220 – 20). If you achieve 180, you achieved
90 percent of maximum.
You want a
positive score. If you have at least zero, your survival rate is 97 percent in
the next decade, says Ahmed.
In the study,
scores ranged from negative 200 to positive 200.
“People 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,”researchers noted.
“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.”
Why fitness
matters.
Of all the
parameters measured, METs and fitness levels were the strongest predictor of
whether a person would live or die, even after accounting for family history,
disease, and health habits, says Ahmed.
“After fitness, age, and gender, almost
nothing else mattered or improved survival.”
How come? The
answer lies in what we know to be true: the vast power of exercise, he says.
“We understand a lot about fitness. And while there is still a lot to learn, we
know that usually, those who exercise more often have lower obesity rates,
lower blood pressure, lower risk of diabetes, a reduced risk of blood clotting,
reduced inflammation, and lower levels of bad cholesterol.”
The good
news:
In a pricey
world of medical testing, medications, and gym memberships, cardio is a free
way to add years to your life.
“We have come
into an age where medical testing is expensive,” says Ahmed.
“This is a
score that costs nothing—it is virtually free besides the treadmill.”
And if you’re
not happy with your fitness levels, there’s room to grow: “Today, we think of
standard stress tests in terms of ‘pass’ and ‘fail’, but that’s an outdated way
to think of risk.”
Just like you
can develop heart disease over years, so too can you build fitness. It’s a
spectrum, he says.
