News Categories
Archives

Two Hearts: Better than One?

Mark McCullough gets to the heart(s) of the Doctor’s alien biology.

Before I start I should make you aware of two things: I have a reasonable amount of medical knowledge and I have nothing better to do. This is the result of that, applying my knowledge to the main protagonist of one of my favourite TV shows. As Tennant’s Doctor would say; “I’m sorry. I’m so sorry”

“What’s the point in two hearts…?”

matt-smith-heartsPerhaps the most fascinating thing about the Doctor is the fact that he has two hearts. As someone who studies anatomy, this raises a lot of questions: how does everything fit inside, what else does he have two of and what effect does it have on the rest of his body? Most of these are unanswerable or can be explained as like his TARDIS his body could be bigger on the inside. That said there are some reasonably firm deductions which can be made about how the Doctor’s body works.

With two hearts there are two options for how the pumps (the hearts) connect to the circuitry (the blood vessels). The first is that the two hearts are in series; that is, both are connected to the same vasculature. Basically the human design with an extra heart added in somewhere along the line. The second option is that the Doctor’s hearts each have their own closed vascular systems. This would mean that each of the Doctor’s organs receives a supply from each heart, essentially getting double the supply which the corresponding human organ would receive. Of these the latter is most likely. Using the evidence present from The Girl Who Waited I can be confident I am right. That fact that a disease only affects organisms with two hearts and not those with one suggests that the disease probably worked by causing an imbalance between the two circulatory systems.

Building on what has been established in the previous paragraph. This would also mean that the Doctor’s lungs would receive twice the amount of blood as a Human would. A quick look at the statistics for Human respiration it is apparent that blood supply is the limiting factor (the one which prevents more happening). I can guess this from looking at the proportions of expired gasses, which contains 16% Oxygen (21% atmospherically) that this is the case. Assuming the Doctor’s blood flow is twice that which we have, it is not unreasonable to assume that he will be able to extract 10% (double what we are able to) from the air.

In the body Oxygen is one of the main drivers of energy production within the body. In particular it is a major input into the process of Respiration; from with we obtain our energy held within food. With twice the oxygen levels that mean that if the Doctor consumed enough food he would be able to obtain twice the energy. What does this mean for the Doctor? Firstly he would be able to hold his breath for much longer periods of time, that’s a given. Perhaps a much more intriguing line of thought involves his ability to regenerate.

“When he’s dying his body, it repairs itself. It changes.”

time-doctor-regen-handThe human body is continually regenerating by a process known as Mitosis. This is where a cell divides into two new ones, thus replacing lost or damaged cells. Unlike in the Doctor’s case DNA needs to be preserved with each division, if not the effects can be disastrous. Much like the Doctor is limited in the number of regenerations, we cannot undergo Mitosis forever. The reason for this is believed to be that the Spindle Fibre shortens slightly each time and eventually reaches the stage where it cannot work. Mitosis is a process which requires a lot of energy, so by what has been established above, Time Lords should be better at it.

That possibly explains how he can change every cell in his body at once, and the residual energy could be effect off as the effect we see onscreen. This still begs the question as to how he is able to alter the DNA within the cell. Since regeneration tends to be a response to injury to the Doctor, I believe it to be an associated response of the immune system. Being a more sophisticated organism he is likely to have higher functioning immune cells. Even humans possess cells which are capable of altering the expression of genes (but not editing the DNA itself). It is possible for the Doctor immune system to go one step further and programme the DNA for a complete change.

Conclusion

It could be possible that the Doctor’s ability to regenerate stems from the fact that he has two hearts. The intention is for this article to be taken with a pinch of salt, as it just a bit of fun speculation. Still, I hope you enjoyed it.

Step back in time...

COMMENT GUIDELINES

Please be civil and keep article comments relevant and on topic. Flag and report any offensive/trolling behavior, or contact us with details.
Please do not post SPOILERS including anything from leaked episodes! Your account could be banned. For complete details on our comment policy please read.
60 comments
pinkjaguar12
pinkjaguar12

I always love reading these articles, considering I am a Biology major myself.  Loving your ideas!

nyma
nyma

Oh I just love mixing science and sci-fi... Possible explanations, theories, back by real life facts. Awesome. Thanks, good article, loved to read it! Now, that part aside, I do like Moffat's explanation: “When they made this particular hero, they didn’t give him a gun, they gave him a screwdriver to fix things. They didn’t give him a tank or a warship or an x-wing fighter, they gave him a call box from which you can call for help. And the didn’t give him a superpower or pointy ears or a heat ray, they gave him an extra heart. They gave him two hearts. And that’s an extraordinary thing; there will never come a time when we don’t need a hero like the doctor.”. Basically, 2 hearts = twice the love power. twice the compassion, the courage. Twice of what are the good traits associated with humanity. That alien Timelord is twice a man. :)



OhLookRocks
OhLookRocks

Isn't it in Underworld that the characters encounter another species who received the ability to regenerate, as a "gift" from the Time Lords? Not sure whether the issue of their heart is addressed though.

Lord of Time
Lord of Time

As to regeneration, I believe Time Lords have triple helix DNA. The third strand was added by Rassilon. I'm not sure where I got this, probably a classic episode.

Moxx
Moxx

This is brilliant, Mark! Fascinating stuff. Sorry I didn't comment last night, but I have a question, O Sciencey One.

You alluded to this in the fourth paragraph, but I'm still a bit confused. Would the Doctor need to breathe twice as quickly/deeply to feed both of his bloodstreams?


Mercy Reborn2
Mercy Reborn2

i like one heart better a great article though

vegalaroche
vegalaroche

The Doctor would have to have two separate systems otherwise each time one of his hearts stops, like in "The Shakespeare Code", "Journeys End" and "The Power of Three"; just off the top of my head he would have died. If both hearts were in the same system then logically both would be affected when something interfered with his systems. If the two systems were one and the same, one stopping would have caused organ failure. Two systems would allow for one to take over more of the work load if the other heart stops. 



The Finn
The Finn

"what else does he have two of..." Oh Mark!





dontfeedjay
dontfeedjay




2 Hearts in a single body has been done. Check it out sometime,  The partient's name is Tyson Smith, and he needed 2 hearts to survive, so they slapped another one in there.  Slapped in this case meaning "Carefully wired and connected all related nerves, blood vessels, veins, and arteries in a grueling and challenging surgery where life was on the line."


















Polyphase
Polyphase

Wether he has 2 hearts in 1 system or 2 systems was answered in Dalek :)

I take it it means the 2nd option

Two hearts! Binary vascular system. Oh, I am so going to patent this. VAN STATTEN

Angie Whodini
Angie Whodini

I absolutely loved this article, especially since it (accidentally?) explains the Doctor's "respiratory bypass" ability. Good job!

Malohkeh
Malohkeh

If I remember correctly, the first Doctor only had one heart, so you may be onto something with it tying into regeneration.

Wibbly-Wobbly is John Reese
Wibbly-Wobbly is John Reese

Thank goodness this article came after my GCSE Biology or I wouldn't have been able to stop thinking about this!  :)

A_Madman_With_a_Box
A_Madman_With_a_Box

I'm studying the immune and circulatory systems right now, this was really interesting!

Benjamin Bradley
Benjamin Bradley

"Assuming the Doctor’s blood flow is twice that which we have, it is not unreasonable to assume that he will be able to extract 10% (double what we are able to) from the air." -- Haha, I guess that explains how he survived jumping out of that spaceship in "The Doctor The Widow and the Wardrobe".




Strontium
Strontium

Very nice article!

Can his hearts change position? I'm pretty sure when we saw them in The Power of Three they appeared to be arranged differently to normal, but I may be wrong.


ChristineGrit
ChristineGrit

Nice article! And you didn't even touch on the ability of handling radicals! A nice new way to look at this. Lovely!

Clara Laurinda
Clara Laurinda

An infoirmed and insightful and lively article Mark! Much appreciated!

B910
B910

There are two schools of thought. One saying that writers and authors purposefully do every clever thing an observer can gleam from their work. The other saying that most if the stuff is dumb luck. I mean no offense to the writers of Doctor Who when I say this entire article probably fits in the latter of the schools.

TheDaleksDaughter
TheDaleksDaughter

Great article! Even if it's pure speculation, it's an interesting theory and it was really fun to read and to follow the developements.

Ninjauthor
Ninjauthor

great article, Im not a medical expert but could the increased supply of energy to the brain be what allows the doctor a greater memory and efficient quick recall of knowledge from that to solve problems faster?


Liana21
Liana21

Nice article, I love it.

VictorWong1
VictorWong1

There are other potential effects. For example, supplying double the oxygen to the Doctor's cells may mean he has a stronger ability to survive a non-existent or toxic atmosphere unassisted by a life-support system; as a corollary, this could mean a body better able to withstand the rigours of time travel.

PaddyB
PaddyB

Really interesting article. What confuses me is how in Human Nature the Doctor using the chameleon arch somehow makes one of his hearts disappear. Any ideas?

PK-S
PK-S

Excellent article, Mark, raising new and original points. Reminds me of Caleb's great Sciency Wiency series - and it's equally good!

Amy is Hannibal
Amy is Hannibal

You know, in Babylon 5, the Centauri race lacks kidneys, so their secondary hearts carry out the same function that their kidneys would if they had them. Maybe it's just something like that.



Notsosmartguy
Notsosmartguy

Nice Article. I'm a sucker for this kind of stuff it adds more depth to fictional universe

MrRazza, the Newly Qualified Omega Identifier
MrRazza, the Newly Qualified Omega Identifier

He certainly seems much better with Oxygen than humans, like in Smith and Jones and the Caves of Androzani


Fascinating and very enjoyable article, I always assumed the extra hearts were for emotional talks...

You know, all those... ahem... Heart Two Hearts...

JFrance
JFrance

Interesting article.  

Zakk Williams
Zakk Williams

Very interesting reading, and original too. I would love for you to write more articles like this one! :)


supermoff
supermoff

Highly original and a very interesting article Mark! It really is an intriguing anatomical feature of Time Lords, and is symbolic and metaphorical as well. 

"Heartbreak is a burden to us all, pity the man with two..."



MeglosProductions
MeglosProductions

Very interesting article, Mark. I've never actually realised this before.

edoe101
edoe101

In all seriousness now, a really interesting article Mark. And I also remember at some point finding out that the Doctor can hold his breath underwater for longer than humans, so that would make sense! You're a medical marvel Mark! Alliteration for the win! 




TardisBoy
TardisBoy

There's no need to apologise about writing this article, Mark! It was very interesting and insightful. I love the sciencey articles, and this one is no exception. Honestly, I had terrible science teachers at school, so I always come away from reading these articles like I've actually learnt something! So thanks for that! Although it does say a lot about my education (or lack of) that I find an article on the internet more insightful than a qualified teacher o_O

The Finn
The Finn

@Lord of Time "Human plus. Specifically, human plus Time Lord." - Mme Vastra, A Good Man Goes To War. A triple helix can be seen on the computer screen in that scene, IIRC.

The Finn
The Finn

@Polyphase  It's been established in other stories too. In both "The Shakespeare Code" and "The Power of Three" he's left with only one working heart. Even though he can't work properly, he's still alive



Lord of Time
Lord of Time

A good example of this is Smith and Jones. However Gallifrey's atmosphere is a bit thinner than Earth's so he was probably used to it a little.

The_Eternal_Dalek
The_Eternal_Dalek

@Benjamin Bradley  Time Lords are also capable of holding their breath for a longer time, they are essentially capable of bypassing their entire cardio-vascular system if it comes to it meaning they could go for several minutes before experiencing any side effects, which would also mean that when they are using it they'd probably need to be using it a lot more.

Calebxy
Calebxy

@PaddyB Well that could be one of the reasons why it was so painful. 

Notsosmartguy
Notsosmartguy

@PaddyB the arch rewrote his entire DNA, so that means he was turned human thus the one heart.