Survival can be defined as the struggle to remain living. In 1869 Charles Darwin used the phrase “survival of the fittest” in his book The Origin of The Species. This is not a statement of the purely physical status of the species but, as he later eluded, that it was the ability to be “better designed for the local, immediate environment”. The human body is physiologically adapted to survive in many environements. Of the many physiological systems that function as parts of the human body, they indeed react to this “local, immediate environment”, that Darwin talked about. Although physiological function of the human body is not, as suggested, the ONLY factor for survival, it is one of the most important. The reason for this is, without this physiological function, the body would fail and death would be inevitable.
Life as a junior doctor is crammed full of physiological and mental challenges for the body and mind. Now, since I have had the pleasure of creating that short online video for TV show The Island with Bear Grylls on how “island life takes its toll on the men”, I’ve been thinking – what, if any, are the comparisons between surviving on a deserted tropical island with only the sort of scarce food that has to be caught and no easy access to drinkable water – versus a 15 hour shift on a particularly traumatic day as a junior doctor. Just a bit of fun really, but lets see what we come up with, shall we? As this is a massive topic that could cover everything from temperature regulation, metabolism, inurgy, illness etc, I decided, for your own sanity, that we’d focus on the the following three key aspects – energy expenditure, fluid balance and stress.
But before we dive into these three, I wanted to show you something that is pretty interesting. It’s called Maslow’s Heirachy of Needs. It suggests what motivates people in life. Now, although designed way back in 1943 it still rings true today (as long as they add in Facebook Status Updates of course…) It’s represented as a pyramind, with the more important aspects of life at the broader base and the less important aspects moving upwards from this towards the apex. How do your own life needs fit in to this?
Right, down to our three comparisons! In a healthy physiological state, free of disease, illness or trauma, the human body prefers a neutral energy balance. This can occur when energy supply from foods are matched to the metabolic demands of the human body. Now this energy is usually supplied in balance by the three main macronutrients: carbohydrates i.e. sugars (45-55%), fats (20-35%), and proteins (10-35%) – and will vary between individuals demanding on their requirements (for example, if your are a hulking bodybuilder you will probably have you diet loaded with protein..). On the island the natural energy balance is clearly swung in favour of an energy imbalance towards insufficient calorie intake. As a result their bodies begin to consume first the sugars and then the fats that exists within their bodies as fuel. In comparison, on my worst shifts as a junior doctor, I will have had breakfast at 5.45am….and not have anything to eat until maybe 10pm that night! Now I can all hear you crying out “HOW IS THIS POSSIBLE!!” – but very sadly it is – there are days were the treadmill of patients, urgent jobs, emergencies and pure unbridled medical chaos just does not end! As a result, my body very quickly uses up the energy from the food I ingested at 5.45am (thank God for Weetabix), uses up the carbodydrates circulating in my blood, and starts to call on the energy reserves that my body has. Firstly this will be the carbodydrates stored as glycogen (mainly in my liver and some in my muscles), and then onto using the fat that helps keep our trousers not requiring that belt! Luckily for me when I get home at 10pm I get to sit down to a nice steak, pint of milk, a banana, and all the fresh water I want. For the men on the island, they don’t have that luxury and so their body flips slowly but surely into starvation mode, peppered with a few paultry meals of snails and fish – and of course the odd, poor, crococidle. May he rest in peace.
Of course that energy from food doesnt just fuel all the metabolic processes within muscles and organs – it also fuels the brain. On the island the men struggle to think, to plan complex tasks and become less and less mentally effective at surviving. Although due to a number of factors, a huge component will be the fact that their brains simply don’t have enough fuel. You see the brain loves carbohydrates – it can use them nicely as a fuel. It dislikes fats because fats struggle to get from our blood and into the brain where it could be used as fuel. In modern society that explains two things: Firstly, why when we grab something sugary to eat we get the mental alertness boost BUT then swiftly followed by the crash (as the carbohydrates are used up so quickly) – and then hence why we immediately grab something sugary again ; And secondly why we feel mentally dull sometimes through our mass consumption of high fat diets in Western society – there is just little fuel for the brain in these diets. On the island of course they are living to survive and so the brain will be sadly lacking in good usuable energy. That is, until the body learns to adapt and adjust in its survival mode that thanks to modern living has laid dorment for year after year. This adaptation includes the manufacturing of ketone bodies – a very special alternative fuel that in survival makes the different between surviving for days or weeks. During my hectic 15 hour largely food-free day having my brain become less effective is clearly dangerous. I mean, that said, it wasnt that effective to start with! And now it’s really ineffective! I find that as my brain struggles to find an fuel, my decision making processes to plan treatments of a patient slows down, is more prone to errors, and my reaction time to perform practical tasks like putting in a cannula or assisting with a cardiac arrest dips massively. Trust me, that sort of mental crash hits you like Serena Williams on Wimbledon Finals Day. That’s why I now always always walk around with food in my scrub pockets – it seems, rather amusingly, that the status of my belly fullness, is pretty important to patient care!
So we come to water. In the words of the Rime of The Ancient Mariner, for the island men it is “water, water, everywhere; nor a drop to drink”. They are having to struggle with transporting, boiling and distilling a lovely pool of stagnant water on a daily basis – and on a mass scale. That means, forgaging for plenty of dry wood to get the fire going all day, transporting gallons of water for the 13 mens huge daily water needs and having to risk infection and gastrointesinal illness causing diarrhoea and vomiting – making them even more dehydrated. For me as a junior doctor, it’s more like “water, water, everywhere; but there’s no time to have a drop to drink”. Again, I hear you scream HOW IS THAT POSSIBLE! On the bad shift days it really can be. In fact, I have gone a good 12 hours without a drink, while running around the hospital like a headless chicken. This is very irresponsible of me – and indeed dangerous – my lesson was swiftly learned let’s say! Now water, being the largest single component in the body at 60% of body weight (approximately 42 L), is unsuprisingly very very important. Water keeps us a alive, and unlike food, where we have been reported to survive for upwards of sixty days, without a drinkable water source, we would die within 3 days give or take the specifics of the situation. When the body starts to run low on water, it works to conserve it. The body has a marvelous system of hormones (known as the renin-angiotensin-aldosterone system or RAAS….yes yes, I know, big yawn…) and nervous system activaton (mainly sympathetic) that works to retain water. The result? Well, as you could see on the island, the mens urine output reduces in volume and turns that wonderfully dark colour as it becomes more concentrated via the work of the kidneys to retain fluid. To top it all off, you will of course pee much less frequently as well. Believe it or not, this is exactly what happens to me by the end of my really horrific days. I can recall leaving work at 10pm at night, and realising I hadnt actually had a pee all day. Thinking, “Oh I better have one”, I go to have a one….not a drop. Dry as a bone. My body was a prune, desperately holding onto water. I have even heard of junior doctors developing acute kidney injury (I am not going to bore you with the details on this occasion) as a result of being so dehydrated. This is something that if left untreated can lead you down a slippery slope to death.
And no, I have not attempted to drink my own urine to survive on a particularly bad shift!
Ok team, I’m realising that I am rambling on for far too long, and you all have better things to do with your time, so I am going to talk about one last aspect: STRESS. Stress is awesome. It prepares you for life – so be thankful for it. Now the physiological response to stress is complex, having three main stages. Stage 1 is the alarm reaction – or the ‘flight or flight’ to you or I; Stage 2 is the resistance reaction; and Stage 3 is exhaustion. For the general public, it is unlikley that we will enter stage 3 for this is very sadly reserved for those that experience prolonged chronic stress, just as the horrors of prolonged combat stress in war day in and day out for an entire tour, and so on. As such I won’t touch on that. But stage 1 we have ALL experienced – whether it be that first date, exam, or just seeing that massive spider out of the corner of your eye. I have ticked all those three boxes! It is essentially a complex set of reactions triggered from a part of the brain called the hypothalamus that stimulates your nervous system and adrenal glands. It all results, almost immediately in more energy release (as you will need it to escape) and more oxygen (supplied via you breathing harder and faster) in preparation for ‘action’. Stage 2 of the stress response is essentially the ‘hormonal back up’ of stage 1. Hormones such as cortisol, your ‘stress hormone’, are released to help bolster all the fast initiating nervous system activities that took place in Stage 1. Now on the island the men are constantly stressed. They have the stress of: meeting 12 other strangers, not being eaten by crocs, finding food, finding water, social in-fighting, being home-sick and so on. Their survival situation screams stress. If there was a reciped for stress – The Island with Bear Grylls is it. And, unfortunately, it will be largely constant for them. This will sadly compound all their other needs for food and for water, as the stress response will increase the consumption of energy and water – and hence the replacement for them. In comparison, I am on the hospital wards. Hmmm, stressful? Yep. Hungry? Yep. Thirsty? Yep. Social in-fighting? Definitely! So my shift sees me in a stressful place. I suppose their is a different stressor as well – looking after people. I can tell you, although (some) doctors may waltz around looking cool as a cucumber, they are all experiencing some degree of stress that comes with looking after others. What if you miss something in the diagnosis? What if you make a mistake in treatment? Someone could die. Similarly on the island, by not pulling your weight, one islander could put the others survival in jeopardy. So stress is shared most definitely. But it’s all relative right? I mean, I am now less stressed than I was 11 months ago. I have grown in confidence, experience and awareness – my stress is therefore more a low lying background noise rather than in my face. For the men of the island, as they gain further control, experience and team-work the stress, although not removed, is controlled.
Right, let’s call it a day here. I need to get a coffee anyway. So I hope that was interesting for you. I am sure too that in your own lives you will have experienced similar episodes of food deprivation, water deprivation and stress, and can relate to some of this personally. I’d like to add too that I can assure you nowadays I make sure I drink plenty, eat healthily and make time for my own health. Being a doctor means I have to look after my own health as much as my patients – a dear (and clearly wise!) friend reminded me of that fact. So next time you watch The Island with Bear Grylls, just ask yourself the question – how do you survive?
Answer – your human body – the greatest machine on earth with enough life, death, adventure and struggle going on under your skin’s surface to rival any Hollywood Blockbuster…
Dr Nick Knight