Abstract:
High
intensity
interval
training
(HIIT)
is
a
novel
mode
of
exercise
training
that
has
been
shown
to
improve
several
components
of
health
in
various
healthy
and
diseased
populations.
Purpose:
The
purpose
of
the
present
study
was
to
examine
hemostatic
adaptations
in
healthy
adult
men
following
four
and
eight
weeks
of
a
HIIT
intervention.
Methods:
Twenty-‐one
healthy
but
sedentary
men
(age:
25
±
5
yrs;
BMI:
26.7
±
6.2
kg/m2)
volunteered
to
participate
in
the
present
study.
Subjects
completed
eight
weeks
of
HIIT
that
included
three
to
six
‘all
out’
Wingate
tests
three
days/week.
Overall
blood
coagulation
was
assessed
at
baseline,
following
four
weeks,
and
following
eight
weeks
by
clotting
times
of
activated
partial
thromboplastin
time
(APPT)
and
prothrombin
time
(PT),
and
plasma
concentration
of
fibrinogen.
Plasma
was
obtained
from
whole
blood
samples
taken
at
rest.
A
repeated
measures
ANOVA
was
used
to
compare
the
overall
coagulation potential.
Significance
was
set
to
p
<
0.05.
Results:
There
were
no
significant
differences
between
resting
heart
rate,
resting
blood
pressure,
APTT
(baseline:
43.0
±
5.4;
4w:
42.7
±
5.1;
8w:
44.2
±
6.2),
and
PT
(baseline:
13.0
±
0.9;
4w:
12.9
±
0.6;
8w:
13.1
±
0.8),
after
4w
or
8w
of
HIIT.
Fibrinogen
concentrations
significantly
decreased
from
baseline
to
4w
(p
<
0.05)
and
significantly
increased
from
4w
to
8w
(p
<
0.05).
Conclusion:
Although
beneficial
fibrinogen
changes
were
seen
following
four
weeks
of
training,
these
findings
were
reversed
after
eight
weeks.
These
observations
suggest
that
HIIT
may
elicit
improvements
in
coagulation
potential
after
four
weeks,
but
continued
training
may
lead
to
elevated
coagulation
and/or
inflammation
via
fibrinogen,
which
is
recognized
as
a
key
regulator
of
inflammation
and
disease.
