Erectile dysfunction isn't exactly the best party conversation. In fact men
rarely talk about reproductive health so there are loads of misconceptions out
there, and one of the biggest is that the inability to maintain an erection, or
erectile dysfunction, is associated with our favorite marker of manliness:
testosterone. So when I was researching for the last episode in the hormone
series I found that a lot of men buy sildenafil citrate, more commonly known
as Viagra, under that exact premise. So while I was in London for VidCon I met
up with cardiologist and YouTuber doctor Rohin Francis of the channel MedLife
Crisis who for a heart doctor sees a surprising amount of ED in his patients.
But why? These body parts seem about as disconnected as can be so how does heart
health impact male fertility and is there any truth to this testosterone
myth and how can we prevent it?
For an organ that we spend a lot of time
thinking and making jokes about, men know very little about how their member works
and even more about the times that it doesn't work. Erectile
dysfunction affects a lot of people and as you'd expect the incidence of ED
goes up with age. We don't have a lot of data globally for how many men it
affects but the ranges go from 50% of US men over age 40 to 20% of all German men.
But you'd never know the numbers are so high because men don't talk about it,
either with their friends or their physicians. Men classically don't go to
the doctors as much as women do and that's especially true when it comes to
issues of fertility. In fact, less than 10% of men who experience reproductive
difficulties will ever seek medical attention.
Now in contrast, huge numbers
of men will buy a product without talking to anyone and we are talking
some big numbers here.
There were about 1 million prescriptions of Viagra in 2006
in the UK but by 2017 that number jumped up to 3 million prescriptions.
Why such an increase?
Well part of it was cost.
The pill went from $7 a pop down to $1.
But the other part was demand.
Advertisements sprang up out of nowhere
making it seem like if you weren't ready to go at all times then you should
be. So not only were men surrounded by perky penises, they weren't talking to
their doctors to see if they even should be taking anything for it. Now one of the
common misconceptions about erectile dysfunction is that it's caused by low
testosterone production which seems like it makes sense.
We know that old men are likely to produce less testosterone than when they
were younger and that they're more likely to experience erectile
dysfunction. And there /are/ some heart health drawbacks that come from having
low testosterone like an increase in total and LDL cholesterol and some of
those markers of inflammation but that's just one piece of the puzzle. Age is
associated with a lot of health issues not just heart disease and you know what
most men don't find particularly arousing? Being reminded that they're old
and need medicine for their heart. So in the 1990s this pharmaceutical company
called Pfizer was testing sildenafil as a possible angina or chest pain
medication in a group of working-age men. And the drug was terribly
unsuccessful at what it was supposed to do and the research was almost
discontinued. But remember, men never talk about sexual health so during those
final interviews when the researchers were asking their routine questions like
"how did you feel / did you have any side effects" they were surprised when a lot
of the participants sheepishly responded that they had had unexplained erections
after taking the pill.
Pfizer instantly reworked their trial format and instead
of investigating sildenafil's effect on chest pain they went in with the
intention of getting it up. But how did this happy accident happen? I mean other
than both being involved in dating, the heart and the genitals don't seem to
have a lot of overlap.
Except you are not your body parts.
You are in fact an entire body, and your systems like your cardiovascular and
your reproductive are all intimately connected and sexual arousal is a really
good example of their intercourse... I mean their interconnectedness!
Also, fair warning you're about to see a penis diagram in three... two.... one....
In healthy men, sexual arousal triggers the release of nitric oxide from a
structure in the penis called the corpus cavernosum - the structures that fill with
blood and make up the bulk of an erection. The clitoris actually has a
corpus cavernosum as well which is what allows it to swell. All that nitric oxide
affects activation of an enzyme between the cells called guanylate cyclase which
regulates some other proteins which ultimately leads to a reduction in
intracellular calcium. Since calcium is needed for muscular contraction, less
calcium means muscular relaxation. Now blood vessels are wrapped in thin smooth
muscle that isn't exactly like the skeletal muscle in your arms and legs
but they can contract and relax around the vessels. When that chain of events is
kicked off by nitric oxide, the relaxation of smooth muscle
loosens the grip around the vessels in the penis, expanding the diameter of
the vessel and allows more blood to pass through which results in an erection. And
that's where sildenafil comes in. The pill doesn't do anything inherently
manly it's just a fancy vasodilator. And that's what I knew I needed the help
of a cardiologist
When Patrick decided he wanted to make a video about erectile
dysfunction he told me that he immediately thought of me. Now either
he's been checking my browsing history or he's aware that there's a huge
overlap between what I treat, heart disease, and erectile dysfunction. When I
see men with heart disease in clinic they rarely mentioned ED but if I asked
it about it it's surprisingly common. Now a strong association between heart
disease and ED has been noted for many years and the traditional view was that
atherosclerosis or the narrowing of arteries that we see in the arteries in
the heart was causing narrowing of arteries to the penis and this is
certainly implicated but it's probably not the main reason. In fact the key
factor is probably the nitric oxide that Patrick was just talking about. The risk
factors for erectile dysfunction and heart disease are pretty much the same:
namely smoking, increasing age, diabetes, high blood pressure, high cholesterol, and
obesity. Nitric oxide causes your blood vessels to open up or vasodilate as
you've already heard it's increased blood flow that causes an erection.
A reduction in your ability to produce nitric oxide or a narrowing of the
arteries will both contribute to impaired vasodilation. Viagra (sildenafil)
or Cialis (tadalafil) and similar drugs all belong to a class of medication
called phosphodiesterase five inhibitors and they work by potentiating or
increasing the effects of nitric oxide. I should say at this point that if you're
already taking any medication please consult with your doctor before taking a
phosphodiesterase 5 inhibitor because they can interact with quite a few
different drugs. If I've got one key message today it's that if you develop
erectile dysfunction don't ignore it. 64% of men presenting to hospital with a
first heart attack experienced some erectile dysfunction in the preceding 12
months before their heart attack. Some even say that erectile dysfunction
should be treated like a risk factor for heart disease
in the same way that smoking or obesity are for example and that after
diagnosing erectile dysfunction there exists a window of opportunity of
perhaps two to three years where heart disease could be recognized and
potentially treated. The reason ED manifests itself earlier is because the
arteries supplying the penis are smaller than the arteries supplying the heart or
your legs for example and so they get affected earlier. So what can you do
about it? Unsurprisingly it's the same lifestyle
modifications that we recommend for someone with heart disease, namely
stopping smoking, achieving a healthy weight, and regular exercise. Exercise in
particular has been found to have powerful effects on reducing ED now
this might be as part of a cardiac rehabilitation program for people with
established heart disease or just regular aerobic and anaerobic exercise
at least three times a week. But remember even if you're very young
prevention is always better than cure and you can reduce your likelihood of
developing any of these problems in the first place by getting in the habit of
taking a regular exercise from any age.
Now you're probably staring at your lap
and planning your diet and exercise regiment as we speak but keep an eye
peeled for a future video collaboration between us about the sweet spot of
exercise and how doing too much might actually be bad for you.