The
amount
of
sleep
you
need
depends
on
many
____________________
,
especially
your
age
.
Newborns
sleep
between
16
and
18
hours
a
day
and
preschool
children
should
sleep
between
10
and
12
hours
.
Older
children
and
teens
need
at
least
nine
hours
to
be
well
rested
.
For
____________________
adults
,
seven
to
eight
hours
a
night
appears
to
the
best
amount
of
sleep
.
However
,
for
some
people
,
"
enough
sleep
"
may
be
____________________
few
as
five
hours
or
as
many
as
10
hours
of
sleep
.
As
you
get
older
,
your
sleeping
____________________
change_
Older
adults
tend
to
sleep
more
lightly
and
awaken
more
frequently
in
the
night
than
younger
adults
.
This
can
have
many
causes
including
medical
conditions
and
medications
used
to
treat
them
.
But
there's
no
evidence
that
older
adults
need
less
sleep
than
younger
adults
.
Getting
enough
sleep
is
____________________
to
your
health
because
it
boosts
your
____________________
system
,
which
makes
your
body
better
able
to
fight
disease
.
Sleep
is
necessary
for
your
nervous
system
to
work
properly
.
Too
little
sleep
makes
you
____________________
and
unable
to
concentrate
.
It
also
____________________
memory
and
physical
performance
.
So
how
many
hours
of
sleep
are
enough
for
you
?
Experts
say
that
if
you
feel
drowsy
during
the
day
?
even
during
boring
activities
?
you
are
not
getting
enough
sleep
.
Also
,
quality
of
sleep
is
just
as
____________________
as
____________________
.
People
whose
sleep
is
frequently
interrupted
or
cut
short
are
not
getting
quality
sleep
.
If
you
experience
frequent
daytime
sleepiness
,
even
after
increasing
the
amount
of
quality
sleep
you
get
,
talk
to
your
doctor
.
He
or
she
may
be
able
to
____________________
the
cause
of
sleep
problems
and
offer
advice
on
how
to
get
a
better
night's
sleep
.
