(panting)
(heartbeats)
- [Simon] If there's one part of my body
that I take for granted, it's my heart.
I'm used to knowing how fast it's beating having ridden
and trained with a heart rate monitor for many, many years.
But I've looked at it as a way of measuring
my training and not as a vital organ keeping me alive.
- Swoons your heart rate.
- But there are many tragic stories
of cyclists suffering from heart attacks
or cardiac arrest when out riding.
Perhaps older riders who've returned to exercise
after years of living the high life or young athletes
whose lives have tragically been cut short.
And then there is a third type, cyclists who have,
like me, taken their hearts for granted for years
and years without a second thought, but who then find
themselves with heart arrhythmia or myocardial fibrosis.
Could that be as consequence of their cycling?
To find out, we have come to meet a cardiologist
with a specialty, and among other things,
sports and exercise.
Dr. Graham Stuart, himself a former Ironman,
runs Sports Cardiology UK which is a company
that provides advice, screening
and assessments for athletes.
So who better then to give us the answers
that we're looking for.
How concerned should we be and what steps
can we take to ensure our long-term health?
And then also, something that I'm actually
really genuinely nervous about, I'm gonna
undergo a screening myself to see
whether I'm actually at risk as well.
(intense music)
(heart monitor beeps)
(rhythmic synth music)
Before we start though, let's recap some basic biology.
A human heart is a muscle.
It's made up of four chambers, two upper ones
called atria, and two lower ones called ventricles.
The right ventricle pumps deoxygenated blood
into the lungs where it picks up oxygen
returning then to the left atrium,
then pumped from the left ventricle
to supply the rest of the body, brain, legs,
et cetera, with that freshly oxygenated blood
before returning to the right atrium.
Now each heartbeat is triggered
by an electrical impulse from your sinoatrial node
and the rate at which it beats varies
depending on input from your brain.
Now what about when things go wrong?
Well, a heart attack is when the supply of blood
to the heart is suddenly blocked,
most commonly as a result of coronary heart disease
which is a build-up of cholesterol.
A cardiac arrest is a sudden loss of heart function
that usually occurs as a result of electrical disturbances
to your heart rhythm called arrhythmia.
A heart attack can lead to cardiac arrest, but as we'll see,
other factors can cause arrhythmia as well.
Now could extreme exercise increase the risk?
- If you have an underlying predisposition
to a heart problem, yes it can.
In general terms, extreme exercise is good for your health,
but there is an element of common sense here.
So, if you're under-trained and you push yourself
too hard, that's not going to do you any good.
If you're doing long-term, extreme endurance exercise,
the evidence seems to be that for the professional
athletes actually you live longer.
What's not clear is where there is a sub-group
where it causes harm and we just don't
really know enough about that, and we know
above a certain level of exercise, just as you're,
no matter how fit you are, if you run down
the span of Wales over five days, you will ache.
- [Simon] Yeah.
- And I think the same is true with the heart,
that above a certain level of exercise,
you will put the whole physiology under strain.
And if you look at somebody's heart after that,
you will find that the right ventricle is enlarged,
the left ventricle is small and most of these changes
get back to normal over a few days.
Sometimes it takes a few weeks,
but if you do a biochemical test, a blood test,
you'll find that the level of a substance
that's actually called troponin is elevated...
- [Simon] Ah, yes, that's what I was worrying about.
Does my heart show signs of damage following 27 years
of riding as fast as I possibly can?
Now, screening isn't gonna show everything,
but it will show most things and it starts
with taking my medical history before then having
an ECG which tracks and monitors
the electrical signals produced by my heart,
and then finally and echocardiogram,
which is a type of ultrasound scan,
therefore using sound waves to create
a moving image of what's going on internally.
(heartbeats)
- When you are exercising, have you ever had
any episodes of chest pain or a racing,
inappropriately racing heartbeats?
- [Simon] No.
- So, your ECG shows a typical athletic
variation called Rd repolarization.
So there's your heart.
Now what I'm gonna do is get you to turn
on your left hand side and put your left hand,
left arm behind your head and you're about to hear
a squirting noise and that squirting noise
is bouncing sound waves off red blood cells
as they cross one of the valves.
(squirting sounds)
So that's crossing the pulmonary valve.
And there, so in this area, for example,
I'm looking for a hole in the heart,
and that's the blood vessel taking blood,
blue blood, out from the body up into the liver.
And what I want you to do in a second is to give a sniff.
(sniffing)
Now you see what happened there?
The blood vessel went from being 24.6 millimeters
to being that size which is 6 millimeters.
(synth music)
- Before we get to my results though,
let's tackle those two other important questions
for older riders returning to sports,
and then for younger riders who might be
at risk of sudden cardiac death.
Right, so, perhaps then we could talk
about three specific categories of people
and firstly would be older cyclists
who are perhaps returning to exercise
having had a number of sedentary years.
Is there a risk to catching this cycling bug
and then entering these quite extreme events maybe
after only a few months or even a few years of training?
- So, if your uncle had a heart attack at 40,
and your dad had a heart attack at 38,
and you're 35, you haven't exercised for 20 years,
but you want to start riding your bike,
you would be very well advised to have
an assessment beforehand, and if you have
that family history you should
be having an assessment anyway.
The most likely thing would be that there was
high cholesterol in your family and that can be treated
nowadays and in fact one of the best treatments is exercise,
but you've got to do that in a graded, sensible fashion.
You want to pick up, if you've got
a coronary artery problem waiting to develop.
The analogy of your leg muscles hurting after exercise,
they hurt an awful lot more if you're poorly trained.
And I think the heart probably behaves in a similar way.
I mean, go back to your question about somebody
who wants to, say somebody who listens
to this said, gosh, I'm gonna have to start exercising.
If they haven't exercised for a long time,
so a typical middle-aged man in like the MAMIL.
You know it used to be the business men
would be out in the golf course, now they're
out on their bikes and they've got all the technology.
I would suggest that they get themselves checked,
and in fact if you go to gym, it will say
on the machine, get yourself checked.
The reason for that is often the very type-A
personality is really wanting to be competitive,
but their bodies need to be gradually built into it,
and they don't actually know if they've
got an underlying issue.
So, I think that group are well-advised to have
a check-up beforehand, and ideally by a sports cardiologist
because it's a specific thing you're looking for.
So, you may say, well, is there anything I should
look out for that might be a red flag
that I should then lead to being assessed.
And probably the most important one is
if you're fainting while exercising.
So if you're running along or cycling along
and suddenly you just feel woozy,
you fall off your bike or you faint,
or you have to stop, that's a red flag.
It may be nothing to worry about,
but certainly you need to be assessed.
Slightly different is the people who feel
that way immediately on stopping exercise,
and that's extremely common.
So you do the Bristol 10K, you then see
quite a few end up just staggering across the line,
then collapsing and then have a drink
and they feel better, and that's just as your body
moves from a high heart rate to a low heart rate,
your blood pressure suddenly plummets,
you're a bit dehydrated, you feel faint.
That's fine, frequent and usually entirely normal.
But if you're running along, feeling fine,
then you go down, that's a red flag.
- The second category, then, would be young adults.
There've been a number of very high profile cases
in cycling over recent years, not huge numbers,
but any one is in itself a tragedy,
but these young people, supremely fit,
talented individuals who die suddenly
of cardiac-related issue.
Is this something that we can give advice
to younger athletes to perhaps learn
whether they're at risk of this?
- The first point I would mention
specifically with cycling but with any sport
is I would ask what supplements are being taken.
Some supplements that involve a very high
caffeine dose can cause you problems.
So that's the first thing, supplements.
Second thing is, is there a symptom
the question was is there a symptom
that they would have to be aware of
that might be a red flag?
Well, again, loss of consciousness
or your heart rate suddenly beating
inappropriately fast or chest pain.
- [Simon] So even in young athletes.
- Even in young athletes, yeah, so the heart beating
inappropriately fast is quite common in young athletes
who have a predisposition to an abnormal rhythm
and for many of these it can be completely cured.
So, if you were to screen everybody.
Say you screened everybody of age 15,
you'd find only a very small number
where they had a preventable cause
of sudden cardiac death, but for that small number
you could potentially save their lives.
There'd also be an even smaller number
where you picked up nothing and they still had
a potentially lethal cardiac problem.
So, at a population level, it's quite difficult
to justify screening.
For any individual, it's much easier, because you may
find that you've got something that's treatable.
You have to bear in count you may find something
that will tell you you can no longer do professional sport,
and that for a professional athlete can be their livelihood.
When you yourself had your screening,
you were aware of the anxiety that it provoked.
Now, thankfully everything's fine,
but it may've picked up something subtle.
For example, a slightly prolonged QT interval
that may have said well you have this potential condition
and we don't actually know what it means
for you as an individual, and therefore, you're left
with uncertainty and then we say, well, we have
to screen your children, we have to screen
your parents, your brothers and sisters,
and we don't actually quite know what it means.
So, there's areas of uncertainty,
and that's the difficult part of screening.
- [Simon] But I suppose the comfort is that you've
put it in the context and that is that statistically
the chances of something happening are minute.
- Exactly.
- [Simon] Okay.
On then to our third group of cyclists,
those who have been riding hard for many years.
It's results time.
- [Graham] And your ECT shows some changes
compatible with being an athlete.
So, your heart rate is relatively slow.
It's not very slow, it's 57 beats a minute.
You have a notch on your ECG there
which is called early repolarization.
Now that's a very common finding in an athlete,
and you also, your initiation of your heartbeat,
the largest upstroke is actually on here.
That little bump is ups, large sub-stroke is there.
Rise and drop logs, it would be there.
- [Simon] Right, okay.
- And that means that your heart rhythm
is initiated from a slightly lower position
than is usual.
These would all be regarded as a normal athletic variant.
Okay?
In fact, in the absence of symptoms,
you wouldn't do anything about any of these.
The third component was the echocardiogram,
and there what I can tell you is that you
have a structurally normal heart.
In other words, there's no holes in the heart.
There's no abnormalities of the valve.
Secondly, that the heart is contracting normally,
and that the heart muscle is of a normal size.
Now that's where it's quite important to know
how much exercise you've been doing.
So, for example, if you were at your peak training
and you were training 20 hours a week,
the heart muscle would probably be a bit thicker
and the heart volume of the left ventricle
and possibly the right ventricle would
also be a bit bigger than in a non-athlete.
So, if I saw a septum of your heart muscle,
which yours was, it was nine millimeters up,
so it was in the normal range for an athlete
or a non-athlete.
If it was 12 millimeters and you did no exercise whatsoever,
I would be suspicious that either you had
high blood pressure or that there was
an inappropriate thickening of the heart muscle.
12 millimeters is a deliberately gray area.
If it was 16 millimeters, that would be abnormal.
whether you were an athlete or not.
- I've read a number of articles with links
to studies that suggest that there
might be a long-term health risk from extreme exercise,
anything from cardiac arrhythmias to myocardial fibrosis
or coronary artery calcification.
Now I'm not sure what two of those three are,
but you know it doesn't sound good.
So, what do you think on those three?
- Right, well, the first question, arrhythmia is,
the short answer is yes, there is.
We mentioned how your heart rate is slow,
and actually your heart rhythm is initiated
from a slightly unusual place, not very commonly
seen in athletes, and that's because of the affect
of long-term exercise.
Athletes tend to have slower heart rates,
and we talked about how that's due
to down regulation of the IKF channels,
and also increased vagal tone.
Now we know statistically that athletes who do
a lot of exercise, particularly endurance
athletes have a higher risk of developing
a condition called atrial fibrillation.
Now atrial fibrillation is a very common arrhythmia
as you get older anyway, but if you've been
a long-term athlete, endurance athlete, it's even higher,
and specifically it's bigger athletes,
as opposed to smaller athletes.
So there's probably an atrial size aspect to this.
We're not entirely sure of the reasons for this.
There's also genetic components.
If your parents have had atrial fibrillation,
you're more likely to get it.
So somebody in my situation, I've done
long-term endurance sport, two parents
who had atrial fibrillation.
I will almost certainly get atrial fibrillation
'cause I'm tall and I've done endurance sport.
Probably higher risk than somebody who hasn't
done all these things, but there's both the genetic
plus there's the behavior aspect to it.
So that risk is probably, I don't know,
four or five times higher than somebody
who didn't do that endurance sport,
but you have to put that in context that,
undoubtedly, the overall benefit of exercise
outweighs a lot of that.
So, by doing long-term exercise you reduce
your likelihood of certain cancers, bowel cancer,
breast cancer if you're a lady, prostate cancer.
You reduce your likelihood of cardiac disease,
degenerative cardiac disease like ischemic heart disease.
You reduce your likelihood of developing diabetes,
maturity-onset diabetes.
You improve your lipid profile.
You strengthen your bones.
Lots and lots of benefits.
So, you have a slightly increased chance
of an arrhythmia disorder, atrial fibrillation,
but greatly reduced chance of all these other things,
and you live longer, that's increasingly clear.
So, atrial fibrillation, it's an arrhythmia
that is now imminently treatable
in an otherwise healthy person.
If you have an area where the heart muscle
is not adequately perfused with blood,
then you can get a scar.
A scar is fibrosis, and we know that sometimes
athletes who've been doing the long-term
endurance athletic activity will have
an increased amount of scar on the heart
and part of that I suspect may've been due
to exercising when they've had a virus,
and so you know that the advice that if you're
achy, your muscles are aching, you should not
be doing exercise, and I think that's good advice
for so-called myocarditis because then you're
exercising a muscle that may be inflamed anyway.
It's possible that myocarditis while exercising
might lead to permanent to scar,
or it can lead to scar anyway.
What's not clear is whether extreme endurance
exercise can lead to scar.
One of the ways we look at the coronary arteries
is we look for calcium scores which are these
blood vessels can get encased in calcium.
They become thickened, and the plaques,
which narrow the calcium-filled arteries,
tend to be more stable than the fatty plaques
that you get from actually having high cholesterol.
So, we know that if you look at a number
of athletes, there seems to be an increased instance
of coronary artery calcification,
particularly in endurance athletes,
but they don't seem to have an increased risk
of heart attacks.
Our hospitals are not full of ex-athletes
having heart attacks.
They're full of smokers having heart attacks,
and people who are obese, and people
who have not looked after themselves.
(guitar music)
- Well, that is another GCN video
that's asking us to confront our own mortality,
definitely a positive take-home message though.
And that is that exercise is overwhelmingly
beneficial to our health although there are
those of us out there that would probably
be advised to seek medical advice
on this particular subject perhaps
because of family history or you're part
of that category of people that is slightly more
at risk either due to lifestyle or your age.
If you would like to see another video
on a health-related subject, this time
on stress and mental health and how cycling
can help it, then you can click on onscreen now.
I'm gonna go put a coat on.