[sound of marker on white board]
DR. MIKE EVANS: Hi, I’m Dr.
Mike Evans and welcome to
this visual lecture I’m calling,
"23 and a Half Hours".
So I have a big interest in
preventive medicine, you know,
which can mean
a lot of things from,
you know, cancer screening,
to eating more fibre,
to having a good social
network and I -- I mean that
in the old sense of the word.
Weighing less, drinking less,
smoking less,
controlling your blood
pressure, cholesterol,
and so on and so forth.
So all these things are
incredibly important and
I wouldn’t want you to
minimize your efforts in
any one category.
But I -- I want to know
what comes first.
What has the biggest
impact, what has
the biggest
return on investment?
[sound of cash register
ringing]
What makes the biggest
difference to your health?
So I did my research, and
I found an answer,
at least for me.
And it's tricky ‘cause,
you know, all these things are
sort of overlapping.
But I picked out this
intervention and --
because of its breadth.
It worked for so many
different health problems,
and that’s what I found
so cool about it.
So just to kind of walk
you through a quick list,
so this intervention in
patients with knee arthritis
who received one hour of
treatment three times a week
reduced their rates of pain and
disability by 47 per cent.
In older patients it
reduced progression to dementia
and Alzheimer’s
by around 50 per cent.
For patients at high risk
of diabetes and coupled with
other lifestyle interventions,
it reduced progression to
Frank diabetes by 58 per cent.
Post-menopausal woman who
had four hours a week of
the treatment had a 41per
cent reduction in the
risk of hip fracture.
It reduced anxiety by 48 per
cent in a big meta-analysis.
Patients suffering from
depression -- 30 per cent
were relieved with low
dose and that bumped to
47 per cent as we
increased the dose.
Following over 10,000 Harvard
Alumni for over 12 years,
those that had the
intervention had a 23 per cent
lower risk of death than those
who didn’t get the treatment.
It’s the number one treatment
of fatigue, and, of course,
the kind of outcome of
choice or my favourite outcome
is quality of life, which is
really all of the above,
and really about making
your life better.
And this treatment has
been shown over and over again
to improve quality of life.
So, the question is,
"What’s –- what’s the medicine?"
And what is "23 and
a Half Hours"?
So the medicine was
exercise, mostly walking.
So not triathlons.
And let me just put it
a different way.
I think what I’m asking
you to do is if you think about
your typical day, so
there's 24 hours,
and so you might spend
most of your day, you know,
this varies obviously, but,
you know, couch surfing,
sitting at work, obviously
sleeping, and what the evidence
that I am going to show
you kind of tells me
is the best thing you
can do for your health
is to spend half an
hour being active,
maybe an hour and that if
you can do that you can realize
all the benefits I’ve described
in the previous slide.
So let’s just take a quick walk
through some of the literature.
So Stephen Blair, he is a
professor at the
Arnold School of Public
Health at the
University of South Carolina,
and he looked at this in
what’s called the Aerobic
Centre Longitudinal Study
which followed over 50,000
men and women over time.
And along the left side of
this graph is something called
Attributable Fractions
which is a kind of fancy word,
but it’s the estimate of
the number of deaths
in a population that
would have been avoided
if that specific
risk factor had been erased.
So for example, turning a
smoker into a non-smoker,
or a couch potato into
a daily walker.
And along the bottom is
the typical risk factors.
You can see the hypertension’s
incredibly important,
and so on and so forth.
But the one that was most
–- that kind of applied the
most risk was this sort of
mysterious CRF which is
Cardio-Respiratory Fitness
which is really low fitness.
So low fitness was the
strongest predictor of death.
And this is important.
Most of the trails we see, to be
honest, are funded by Pharma,
or other companies because
they’ve got a drug for
hypertension or high
cholesterol or diabetes.
And we rarely see fitness
thrown in to the mix.
And so it’s nice to see a
trial that’s not so siloed.
[sound of bicycle bell]
Blair’s work is interesting.
He also did another trial
looking at obesity.
What he found was, you
know, sort of two things.
One is obesity and no exercise –
that’s a very bad combination
and that’s where we saw many
of the negative consequences
of obesity from a
health point of view.
But if the –- if the obese
person was active,
even if they didn’t have
the weight loss,
but were just active and
obese, that was much,
much better and that the
exercise ameliorated
much of the negative
consequences of obesity.
So if exercise is the
medicine, what’s the dose?
So when I think of dose,
I think of how long,
how often and how intense?
I’m going to give you a
slightly mixed message,
but essentially, more
activity is better.
But I must say the rate of
return seems to decline
after 20 or 30 minutes a
day so if you’re being active
less than 150 minutes a
week or more if you’re a kid --
an hour a
day if you are a kid,
my flag goes up in the clinic.
So my personal take on
this is that, you know,
the literature draws
a very broad brush
and so we see big
differences when somebody
goes from not doing
anything to doing something.
And after that the return
is more granular.
So if we took the nurse’s health
study, women who went from
zero activity to just
one hour a week,
reduced their heart disease
rates by almost half.
So you can break it down
so it can be 10 minutes,
10 minutes, 10 minutes if
you want to do 30 minutes
of exercise so it can be
broken into three.
Higher intensity -- it
looks like it’s equivalent
to less time with
lower intensity.
But I think obviously the
clinical pearl is mostly of
thinking about your style and
habits and your personal cues.
So if you’re only going to
do it if it is pre-booked
with friends, you know,
I’ve couples who take
a half hour walk every
morning or evening to
organize their life.
A dog is a great walking coach.
[sound of dog barking]
The data’s showing
67 per cent of dog walkers
achieve the 150 minutes a
week just with the dog walking.
And finally, of course,
your commute.
You know, getting off a
stop early, taking the stairs,
and so on and so forth.
So thinking about that, I’m
just going to walk you through
some quick slices
of the literature.
And the first one
comes from Japan.
In the 90s, Japan required
all employers to conduct
annual health screenings
for their employees.
And so a large gas company
in Japan called Osaka
used this to answer
a great question.
So if people’s walk to
work was longer,
did that reduce their chance
of serious health problems?
So in this example,
high blood pressure.
And what they found is under 10
minute walk, no difference;
11 to 20 minute walk,
12 per cent reduction
in rates of high blood
pressure or hypertension;
and over 21 minute walk,
a 29 per cent decrease
in rates of high blood pressure.
So the authors calculated
that for every increase of
10 minutes in your walk to
work there was a 12 per cent
reduction in the likelihood of
getting high blood pressure.
The second exhibit is
looking at stents.
So this is something we
commonly do now in medicine.
So you can see on the left
that the artery is blocked;
on the right, a vascular surgeon
has gone in and put a balloon,
open it up and left
a stent to keep it open,
which makes great sense.
So a German researcher
named Rainer Hambrecht
looked at this with about
100 cardiac patients.
He got half the group to
exercise and by that I mean
20 minutes a day on
an exercise bicycle and
then a once weekly 60
minute aerobics class.
And the other half got the
high tech stent and just
sort of normal activity.
And after one year, 88 per
cent of the exercisers
were event-free compared
to 70 per cent of the people
that got a stent.
So both worked, but I find it,
you know, sort of incredible
that the low tech made a
bigger difference.
And you have to remember
that the stent just fixes
one part of the heart.
The next way to think
about it is the reverse,
so what I call
“sitting disease”.
We know that being sedentary
is bad for your health
but a researcher
named Leonard Veerman
wanted to quantify this
and he did so down in Australia
in a big study
that he did there.
They found comparative
persons who watched no TV;
those that spent a lifetime
average of six hours a day
watching TV can expect to
live about five years less.
I mean that’s incredible.
But then I think, “Oh, who
watches 6 hours of TV?”
It turns out the average
adult in the USA spends about
five hours a day
watching TV or screens.
So I find this fascinating
that we never think of the TV
as something that’s bad
for our health,
but clearly it’s as powerful
as many other risk factors
for chronic disease.
So I’m just going to
leave you with, well,
I guess, two quotes.
So one is Jerry Garcia, the
singer who is the lead singer
for The Grateful
Dead, and he said,
“Somebody has to do something.
It’s just incredibly pathetic
that it has to be us”.
And I think that’s true, that
in some ways it has to be us.
As Hippocrates said, “Walking
is man’s best medicine”.
And so I’m going to finish
by asking you a question.
And this may have some
personal challenges for you,
so you know, you
might be very busy with work
or kids or both and
-- or you may be in pain
or have other priorities,
but my question to you is,
“Can you limit your
sitting and sleeping to just
23 and a half hours a day?”
So, something to think about.
Thank you very much.
[sound of marker on white board]
