What is Aerospace Medicine?

[This page is about the field of Aerospace Medicine. To find out more about the UK medical speciality of Aviation & Space Medicine, click here]

Despite what the name might suggest, Aerospace Medicine is about much more than just being a doctor for aviators or astronauts. In fact it is much more than just ‘medicine’ in general and needs much more than just doctors. We rely on a huge interdisciplinary team including psychologists, physiotherapists, nurses, doctors, engineers, physiologists and other pure scientists amongst many others to allow people to fly safely. To describe what Aerospace Medicine is, it’s perhaps best to start at what it isn’t:

AEROSPACE MEDICINE IS ALL ABOUT SPACE, RIGHT?

No. Aerospace medicine is just a shorthand way of saying ‘Aviation and Space Medicine’ (which is actually the name of the UK medical speciality – also known as ASM). Whilst there are some aspects of Space Medicine that are unique, such as microgravity, most of the environmental stressors of space are the same as those in aviation, just to a different magnitude (barometric pressure, thermal, motion sickness, cosmic radiation etc). Aircraft have been around for longer and far more people fly regularly than go to space so there is a wealth of evidence from the aviation environment. Many lessons have been learnt (sometimes at great cost) that can be applied to the space environment. Here at NGAM we believe the two areas should be viewed as one inseparable field – another reason we prefer the term ‘Aerospace’.

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YOU’RE ALL ROCKET SURGEONS

Nope (however cool that t-shirt is). Whilst the clinical care of aviators and astronauts is a full time career for some in the field, Aerospace Medicine is much broader than just doing medicine in a different location. The speciality is far more focused on making sure people don’t get sick in these environments than treating them when they do (even aeromedical evacuation is all about trying to prevent deterioration in flight) – in the US, aerospace medicine is learnt alongside preventative medicine for this very reason.

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AEROSPACE MEDICINE IS JUST FOR DOCTORS

Absolutely not. Aerospace medicine relies on a huge multi-disciplinary team – there are aviation physiotherapists, aerospace physiologists, space psychologists, aircraft ergonomists, oxygen system technicians and much much more!

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AEROSPACE MEDICINE IS JUST FOR NASA AND THE MILITARY

Wrong again! Certain aspects of aerospace medicine are encountered more regularly in specific types of operations but most are relevant across the civilian, military and governmental sectors. For an example, whilst the effects of +Gz acceleration are more commonly encountered in the military sphere these days, the challenge was first recognised in civilian air races in the 1920s and still apply today in aerobatics and air races. Whilst your 747 might not be pulling ‘9Gs’ , commercial aviation carries its own set of challenges such as public health issues, fatigue from shift work and even the risk of cosmic radiation.

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With that out of the way, let’s focus on what it really is. The best way to do this might be to break it down a little bit:

We have all evolved to live at ground level – with a barometric pressure of around 760mmHg, an F_IO₂ of approximately 148mmHg, a gravitational ‘pull’ of approximately 9.81m.sec^-2, a radiation dose of approx. 2-6.5mSv per year, an atmospheric density of around 1.3 kg.m^-3 and a relatively narrow temperature range – and, generally speaking, we’re pretty happy here.

Whilst we can acclimatise pretty well if we travel slowly to relatively low altitudes (and long-term adaptations do occur in certain populations living at altitude for a number of generations), all it takes is a quick look at some of the differences in avian physiology to realise that we are not evolved to take relatively quick jaunts into the sky or space and back.

Both the aviation and space environments are hostile and will try their best to kill you.

Click here for a quick glimpse into how this might happen

If you were to strap a weather balloon to your deck chair (whilst you wouldn’t be the first, do not try this at home!) you would learn this the hard way. As you ascend you would start to get cold (temperature drops by 1.98°C per 1000ft until the thermopause). Your ability to think clearly would be reduced too. Whilst your body would try its best to adjust by hyperventilating, increasing your heart rate and more, the change would be too quick. As you carry on upward, puffing away all your carbon dioxide, your fingers might start to tingle, but you probably wouldn’t notice as the hypoxia starts to affect your attention and makes you pleasantly giddy. Further still and you might suffer decompression sickness, but you’ll probably have passed out before this. If you somehow made it all the way to 63,000ft PA (even 100% O₂ wouldn’t be enough to keep you conscious and it’s -56.5°C up here!) your tissue fluid would start to boil…and this is just some of the effects of altitude alone! Our planned series of tutorials will aim to teach you more about the aviation and space environments and the impacts on our terrestrial physiology.

But let’s not rush to that yet…

Just like the key to understanding medicine is understanding what normal looks like, to understand what the aviation and space environments do to our minds and bodies, we need to know how they work in a normal environment first.

Then we need to know all we can about the environments in question. What changes? How quickly?How can this vary? etc. Only then can we try and predict what might happen to normal physiology in these new environments. After that we need to test that to see if our theories hold up and come up with ways to protect against these environmental challenges.

To look after the health of aviators and astronauts (and passengers!) we need to take yet another couple of steps. We need to know what disease (and treatment of disease) does to our bodies in the normal environment. We can then combine this with our recently gained knowledge, to see how our hostile environment might affect these disease processes (a bit of a hint: if you’re hypoxic at ground level, it’s not going to get better by going up!).

The final step (that just wouldn’t quite fit on the diagram) is knowing what we expect people to do in these environments. Are they sitting still watching an in-flight movie, or are they performing flight critical tasks whilst straining against +Gz? This will affect how much protection they need and also what conditions we might accept – whilst neither is good in the air, the potential outcomes of someone in a critical role such as piloting suddenly becoming incapacitated due to a medical condition are quite different to if the same occurred to a passenger. Similarly, whilst conditions that might subtly affect cognition or response time probably won’t spoil your enjoyment of the in-flight meal, they may be disastrous if you’re in control of the aircraft.

This is what we do in aerospace medicine. We learn about people, we learn about their environment and we learn what they need to do in that environment. Then we try and make sure it all happens as safely as possible.

And on the sad occasions when it goes wrong? We learn from that too and try to stop it happening again.

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What Is ‘Aviation and Space Medicine’?

Aviation and Space Medicine (or ASM for short) is the GMC approved speciality for doctors who work full time in aerospace medicine. You can find out more about this here…

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