Do
fitness
trackers
make
you
fitter
?
A
Fitbit
or
similar
fitness
tracker
was
on
top
of
many
Christmas
wish
lists
last
year
.
It
not
only
appealed
to
someone
that
wanted
to
keep
fit
,
but
also
to
those
that
wanted
to
lose
weight
or
monitor
their
state
of
health
in
general
.
Fitness
trackers
have
,
in
just
a
few
years
,
become
a
global
one
billion
dollar
industry
.
They
work
by
measuring
movement
.
The
is
worn
on
the
arm
and
it
is
body
movement
through
that
can
follow
motion
in
all
directions
.
The
data
collected
is
then
converted
into
steps
,
calories
,
and
other
activity
.
This
information
can
then
be
viewed
on
a
smartphone
app
.
Some
trackers
even
allow
you
to
see
how
high
you
have
climbed
or
how
many
stairs
you
have
and
.
Other
trackers
send
data
showing
the
heart
-
rate
and
the
sleep
patterns
of
the
person
wearing
the
device
.
Most
makers
admit
that
there
is
some
and
estimating
used
when
converting
movement
data
into
steps
and
even
more
when
measuring
a
person's
state
of
health
.
The
reason
for
this
may
be
clearer
if
we
a
similar
situation
:
imagine
you
are
at
a
large
music
concert
and
you
decide
to
record
the
event
.
You
switch
on
your
cell
phone
and
press
the
record
button
.
However
,
when
you
listen
back
later
,
you
notice
that
you
have
recorded
the
music
but
you
have
also
recorded
lots
of
other
noises
?
people
shouting
and
cheering
,
for
example
.
If
you
want
to
hear
only
the
pure
music
you
have
to
remove
all
these
other
noises
from
the
recording
you
made
.
This
process
is
what
a
good
tracker
needs
to
do
too
.
It
is
not
easy
.
No
one
would
disagree
with
the
fact
that
it's
a
good
thing
that
people
want
to
improve
their
.
It
is
a
well
known
fact
that
a
large
number
of
people
would
benefit
from
doing
more
exercise
.
It
is
also
interesting
to
have
clear
information
about
your
health
,
sleep
patterns
,
blood
pressure
,
etc
.
without
the
need
to
visit
a
doctor
.
So
what's
the
problem
?
Well
,
the
first
thing
is
?
as
you
read
above
?
the
data
is
not
very
precise
.
If
you
were
to
wear
three
trackers
,
all
at
the
same
time
,
they
would
all
give
different
results
.
Moreover
,
most
experts
agree
that
movement
is
not
a
good
guide
to
sleep
patterns
.
Does
all
this
matter
?
Probably
not
.
The
arm
bands
are
more
about
getting
people
to
get
up
and
go
than
giving
them
precise
data
.
They
are
very
easy
to
use
and
read
.
They
keep
thoughts
about
fitness
and
health
at
the
front
of
their
minds
.
What
might
worry
users
more
perhaps
,
is
what
happens
to
all
this
data
.
Who
owns
it
?
Will
it
be
sold
to
advertisers
or
?
These
are
important
questions
that
,
right
now
,
have
no
answers
.
Let's
check
your
understanding
!