Experimental Physiology,
Год журнала:
2024,
Номер
109(10), С. 1768 - 1781
Опубликована: Авг. 27, 2024
Acute
ingestion
of
exogenous
ketone
supplements
in
the
form
a
(R)-3-hydroxybutyl
(R)-3-hydroxybutyrate
(R-BD
R-βHB)
monoester
(KME)
can
attenuate
declines
oxygen
availability
during
hypoxic
exposure
and
might
impact
cognitive
performance
at
rest
response
to
moderate-intensity
exercise.
In
single-blind
randomized
crossover
design,
16
males
performed
assessments
before
with
moderate
exercise
[2
×
20
min
weighted
ruck
(∼22
kg)
3.2
km/h
10%
incline]
normobaric
altitude
chamber
(4572
m,
11.8%
O
Experimental Physiology,
Год журнала:
2024,
Номер
109(10), С. 1672 - 1682
Опубликована: Авг. 27, 2024
Abstract
Exogenous
ketone
supplements
are
a
potential
augmentation
strategy
for
cognitive
resilience
during
acute
hypoxic
exposure
due
to
their
capacity
attenuate
the
decline
in
oxygen
(O
2
)
availability,
and
by
providing
an
alternative
substrate
cerebral
metabolism.
Utilizing
single‐blind
randomized
crossover
design,
16
male
military
personnel
(age,
25.3
±
2.4
year,
body
mass,
86.2
9.3
kg)
performed
tests
of
performance
at
rest
three
environments:
room
air
(baseline),
normoxia
(20
min;
0
m;
20.9%
O
hypoxia
6096
m,
9.7%
using
reduced
breathing
device
(ROBD).
(
R
)‐3‐Hydroxybutyl
)‐3‐hydroxybutyrate
(R‐BD
R‐βHB)
monoester
(KME;
650
mg/kg,
split
dose
given
30
min
prior
each
exposure)
or
taste‐matched
placebo
(PLA)
was
ingested
exposure.
Blood
R‐βHB
glucose
concentrations,
saturation
()
were
collected
throughout.
KME
ingestion
increased
blood
concentration,
which
rapid
sustained
(>4
mM
post;
P
<
0.001)
accompanied
lower
concentration
(∼20
mg/dL;
0.01)
compared
PLA.
Declines
exposure,
assessed
as
efficiency
Defense
Automated
Neurobehavioral
Assessment
(DANA)
code
substitution
task,
attenuated
with
leading
6.8
(95%
CL:
1.0,
12.6)
more
correct
responses
per
minute
PLA
=
0.018).
The
(6.40%
;
95%
0.04,
12.75;
0.049)
(KME,
76.8
6.4%
PLA,
70.4
7.4%
).
Acute
severe
coincided
attenuation
declines
saturation.
Revista de Gestão Social e Ambiental,
Год журнала:
2025,
Номер
19(1), С. e010458 - e010458
Опубликована: Янв. 23, 2025
Objective:
Identify
the
protocols
used
in
normobaric
hypoxia
and
main
symptoms
that
context.
Theoretical
Framework:
Hypoxia,
particularly
hypoxic
hypoxia,
is
a
critical
challenge
aviation,
caused
by
reduced
atmospheric
pressure
at
high
altitudes.
Controlled
training
allows
aviators
to
recognize
symptoms,
assess
time
of
useful
consciousness,
practice
emergency
responses.
This
study
synthesizes
key
parameters
training,
addressing
gaps
oxygen
concentrations,
exposure
times,
symptom
monitoring.
Method:
Systematic
electronic
searches
were
conducted
MEDLINE
Embase
databases.
Inclusion
criteria
required
original
studies
involving
aircraft
crews,
descriptions
gas
mixtures
for
altitude
simulation,
details
simulated
altitudes
during
training.
Results
Discussion:
From
295
identified
articles,
eight
met
inclusion
criteria.
Sample
sizes
ranged
from
8
89
participants,
predominantly
male.
Protocols
varied
widely,
with
O₂
concentrations
6%,
7%,
8%
frequently
simulate
25,919
feet
(7,900
m)
20,341
(6,200
m).
Considerable
heterogeneity
was
found
same
altitude,
likely
due
differences
equipment
calibration.
Continuous
periods
three
five
minutes
common,
diverse
reported,
emphasizing
importance
recognition
operational
safety.
Research
Implications:
offers
practical
insights
standardizing
protocols,
enhancing
safety
procedures,
developing
guidelines
environments.
Originality/Value:
By
synthesizing
parameters,
this
research
highlights
need
protocol
standardization
ensure
aviator
efficiency.
Abstract
As
the
altitude
increases,
partial
pressure
of
oxygen
will
decrease
and
cause
hypobaric
hypoxia
conditions.
During
hypoxia,
anaerobic
glycolysis
be
activated,
which
is
facilitated
by
lactate
dehydrogenase
(LDH)
enzyme.
This
study
aimed
to
analyze
LDH-specific
activity
in
rat
muscle
liver
tissue,
as
well
glucose
levels
blood
plasma
after
intermittent
exposure.
Twenty-five
Wistar
rats
were
divided
into
five
groups:
one
control
group
four
(HH)
exposure
groups
consisting
1
(1×
HH),
2
(2×
3
(3×
4
(4×
HH)
with
a
range
7
days
between
found
that
increased
tissues
1,
but
then
decreased
(groups
2–4).
The
change
was
similar
levels.
Interestingly,
tissues,
there
slight
increase
it
started
significantly
kept
increasing
4.
level.
We
conclude
LDH
tissue
contributes
levels,
maintaining
exposures.
finding
could
implemented
individuals
who
experience
exposures
or
various
diseases
hypoxic
conditions
their
pathogenesis
Scientific Reports,
Год журнала:
2025,
Номер
15(1)
Опубликована: Март 8, 2025
Despite
extensive
research
on
neuroimaging
correlates
of
human
brain
aging,
there
is
little
mechanistic
insight
into
how
they
are
linked
to
loss
function.
Previous
studies
the
role
cerebral
blood
flow
(CBF)
in
supporting
function
have
focused
delivery
nutrients,
namely
oxygen
and
glucose.
However,
CBF
required
also
clear
byproducts
energy
metabolism,
CO2
protons.
With
goal
determining
whether
age-associated
reduction
regional
may
lead
abnormal
partial
pressure
carbon
dioxide
(pCO2)
pH
levels
that
sufficient
alter
activity
cognitive
function,
we
applied
a
recently
introduced
homeostatic
modeling
nutrients
waste
products
PET
data
acquired
young
older
adults
(Goyal
et
al.
Cell
Metab
26(2):353–360,
2017).
Our
results
demonstrate
reductions
CBF,
presence
virtually
unaltered
consumption
rates,
show
concurrent
increases
pCO2
associated
acid-shifts
possible
functional
relevance.
We
conclude
implications
altered
vascular
health
needs
be
revisited
light
its
central
removing
from
metabolism
at
resting
state
and,
future
studies,
during
external
stimulations.
PLoS ONE,
Год журнала:
2023,
Номер
18(8), С. e0289716 - e0289716
Опубликована: Авг. 16, 2023
Recovery
of
cognitive
and
physiological
responses
following
a
hypoxic
exposure
may
not
be
considered
in
various
operational
research
settings.
Understanding
recovery
profiles
influential
factors
can
guide
post-hypoxia
restrictions
to
reduce
the
risk
further
deterioration,
potential
for
incidents
accidents.
We
systematically
evaluated
available
evidence
on
basic
an
acute
improve
understanding
performance
safety
implications,
inform
restrictions.
This
systematic
review
summarises
30
studies
that
document
either
or
index
from
exposure.
Titles
abstracts
PubMed
(MEDLINE)
Scopus
were
searched
inception
July
2022,
which
22
full
text
articles
eligible.
An
additional
8
other
sources
identified
also
The
overall
quality
was
moderate
(average
Rosendal
score,
58%)
there
large
range
exposures.
Heart
rate,
peripheral
blood
haemoglobin-oxygen
saturation
heart
rate
variability
typically
normalised
within
seconds-to-minutes
return
normoxia
hyperoxia.
Whereas,
performance,
pressure,
cerebral
tissue
oxygenation,
ventilation
electroencephalogram
indices
could
persist
minutes-to-hours
exposure,
one
study
suggested
regional
oxygenation
requires
up
24
hours
recover.
Full
most
indices,
however,
appear
much
sooner
~2–4
hours.
Based
these
findings,
is
support
‘hypoxia
hangover’
need
implement
severity
duration
unclear
but
should
consider
population,
subsequent
requirement
safety-critical
tasks
