What are the chances you will live for another ten years?
While
your GP might give you some idea, scientists now say you can accurately
predict your likelihood of death using a calculator and a treadmill.
The process involves running in three-minute segments on a treadmill with an increasing speed and at a growing incline.
Runners then plug in their vital statistics into a basic formula to find out how likely they are to die over the next decade.
Dubbed
the FIT Treadmill Score, the test was created by cardiologists at Johns
Hopkins University in Maryland after studying 58,000 stress exams
'The
notion that being in good physical shape portends lower death risk is by
no means new,' said lead investigator Haitham Ahmed.
'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.'
As
well as 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.
This
is a gauge of how much energy the body expends during exercise. More
vigorous activities require higher energy output – or higher METs.
An activity such as slow walking equals two METs, compared with eight for running.
For
the study, the team analysed 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.
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 per cent risk of dying over the next
10 years, while those with scores between 0 and 100 faced a 3 per cent
death risk over the next decade.
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 per cent risk of dying.
'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.
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
Exercise
stress tests usually measure how well the heart and lungs respond to
physical exertion while a person is walking on a treadmill at
progressively higher speed and elevation.
The
test is stopped once a person reaches the point of exhaustion or
develops chest pain, dizziness or heart rhythm abnormalities.
Those
who have normal readings and no alarming symptoms while exercising are
said to have 'normal' results and typically do not require further
testing.
However,
the researchers say, the new data show varying degrees of fitness among
those with 'normal' stress test results that reveal telling clues about
cardiac and respiratory fitness and, therefore, overall death risk over
time.
'Stress
test results are currently interpreted as 'either/or' but we know that
heart disease is a spectrum disorder,' Dr Ahmed says.
'We
believe that our FIT score reflects the complex nature of
cardiovascular health and can offer important insights to both
clinicians and patients.'
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