When this becomes available you will want this test so you can monitor how effectively your doctor is getting you to the correct level of exercise and if you are getting enough exercise to prevent dementia.
Study details molecular effects of exercise
MedicalXpress Breaking News-and-Events|May 28, 2020
A
simple blood test may be able to determine how physically fit you are,
according to a new study conducted by scientists at the Stanford
University School of Medicine.
The
test could complement treadmill tests, a more traditional clinical
evaluation of fitness, and provide individuals with far more nuanced
information about their body's molecular response to exercise.
The
blood test is an offshoot of a complex study conducted by a team of
researchers that took hundreds of thousands of molecular measurements
from a group of individuals before and after exercising.
"Everybody
knows exercise is good for you, but we really don't know what drives
that at a molecular level," said Michael Snyder, PhD, professor and
chair of genetics. "Our goal at the outset was to conduct a highly
comprehensive analysis of what's happening in the body just after
exercising."
The team tracked molecular
markers of a wide array of biological processes, such as metabolism,
immunity, oxidative stress, and cardiovascular function. Hundreds of
thousands of measurements from 36 study participants provided a window
into the sea of chemical fluctuations the body experiences during
intense exercise. To the scientists' knowledge, such comprehensive
measurements of post-exercise molecular fluctuations have never been
performed. What's more, the team saw that the participants who were most
physically fit shared similar molecular signatures in their resting
blood samples captured before exercise.
"It
gave us the idea that we could develop a test to predict someone's level
of fitness," said Kévin Contrepois, PhD, director of metabolomics and
lipidomics in the Department of Genetics. "Aerobic fitness is one of the
best measures of longevity, so a simple blood test that can provide that information would be valuable to personal health monitoring."
With
the preliminary data, the team has created a proof-of-principle test,
for which they've filed a patent application. The test is not currently
available to the public.
A paper describing the study will be published May 28 in Cell.
Snyder, who holds the Stanford W. Ascherman, MD, FACS, Professorship in
Genetics, and Francois Haddad, MD, clinical professor of medicine, are
co-senior authors of the study. Contrepois shares lead authorship with
postdoctoral scholars Si Wu, PhD, and Daniel Hornburg, PhD, and with
clinical assistant professor Kegan Moneghetti, MD, PhD.
A flurry of change
Snyder's
team set out to better understand the molecular shifts that underlie
changes in physical fitness. The gold standard of medical fitness
assessments is a peak VO2 test, which measures a person's peak oxygen
consumption during intense exercise and uses the score as a proxy for
aerobic fitness. But Snyder and his team wanted more
detail—specifically, about the ways in which exercise initiates change
at the molecular level.
They
performed VO2 testing for 36 individuals, including Snyder, on a
treadmill. Participants, both male and female, had an average body mass
index of 29 kilograms/meter squared, and their age range was from 40 to
75 years old. Before the treadmill test, the researchers drew a baseline
blood sample. Participants then donned an oxygen-measuring mask and ran
at a slight incline until they reached peak oxygen consumption, at
which point they stopped and got off the treadmill. The researchers took
blood samples from participants 2 minutes, 15 minutes, 30 minutes and
60 minutes after they had reached their peaks.
"All
of these measurements allow us to describe a choreography of molecular
events that occur after physical exercise," Snyder said. "We know that
exercise causes an array of physiological responses, such as
inflammation, metabolism, and hormone fluctuation, but these
measurements allowed us to characterize those changes in unprecedented
detail."
It turns out that in the first 2
minutes post-exercise, the body experiences an intense flurry of
molecular activity. In most participants, molecular markers of
inflammation, tissue healing and oxidative stress, a natural byproduct
of metabolism, spiked sharply shortly after hopping off the treadmill,
as their bodies began to recover. Molecular markers of metabolism
varied, Snyder said. At 2 minutes, blood samples revealed evidence that
the body was metabolizing certain amino acids for energy, but it
switched to metabolizing glucose, a type of sugar, around 15 minutes.
"The body breaks down glycogen as part of its exercise recovery
response, so that's why we see that spike a little later," Snyder said.
Glycogen is a form of stored glucose.
As part
of the study, Snyder also compared the molecular response in individuals
who were insulin resistant, meaning they're unable to process glucose
properly, with the response in individuals who could process glucose
normally. "The main difference we see is that insulin resistant
individuals have a dampened immune response post-exercise," he said.
Blood test for fitness
Although
it wasn't the team's original intent, they noticed some consistencies
in the baseline measurements of the participants who performed better on
the peak VO2 test. In these individuals, the researchers saw a strong
correlation between a set of molecules and an individual's level of
aerobic fitness. They discovered a collection of thousands of
molecules—including markers of immunity, metabolism and muscle
activity—that correlate with a person's aerobic fitness. "At this point,
we don't fully understand the connection between some of these markers
and how they are related to better fitness," Snyder said. The
researchers hope to unravel those connections in a future investigation.
Snyder
said that because the molecular profiling done in the study was so
thorough, it wouldn't be practical for doctors to use in their clinics;
it would be expensive and provide more information than necessary. But
his team is working on whittling down the biomarkers to those that are
most representative of a person's fitness level in an effort to make the
test practical for broader use. Already, the team is developing an
algorithm to select a subset of these molecules that are highly
correlative to peak VO2 results, Contrepois said. As the researchers
continue to optimize the fitness test, they hope it can one day be a faster, cheaper and more convenient way for people to objectively measure aerobic fitness.
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