About The Writer

HC James is from London and worked as a teacher before switching careers to medicine. He currently works as a doctor in a south London Emergency Department and in his spare time visits family in California.   

 

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The Central Governor

What is the 'subtle body'? It is an idea, borrowed from the 'liberation' tradition of Tantra, to describe qualities of the human organism that slip beneath the radar of our day-to-day awareness. It includes such concepts as the survival instinct, a set of subconscious drives that influence our health and behavior. It proposes that our senses - both overt and subtle - essentially tie us to our outer world, that essentially there is no such thing as 'outside'. It is a body interconnected in ways we are only really beginning to appreciate. It is influenced by our moods, our thinking, our emotional state. However, most of the time we are out of touch with this body, so caught up in our mental processes that it becomes something separate from us. 

In this section we will explore another facet of the subtle body. This is the 'central governor model'. Like the survival instinct, the central governor is based in the nervous system. Its main role is preventing damage to the body and governing the use of energy. Energy is our most valuable resource and we have evolved various ways to tightly control its use. In times of plenty, for instance, excess energy is stored as glycogen and fat. In straightened times, fat and glycogen are broken down to glucose. In a fasted state the body releases growth hormones to preserve muscle mass, though if this tips over to a starvation state muscle will also get broken down for fuel. 

As well as controlling the amount of energy we use, the body also works to prevent damage to the organism. One way it does this is through our sense of pain, which is a bit like an early warning system and, unwelcome though it is, pain usually kicks in before any damage is done to us. Another way it protects is through the sensation of fatigue, and this is where the central governor model comes in. This theory has been developed mainly in the area of sports medicine, in studying endurance athletes such as marathon runners and high altitude climbers. The conventional wisdom since the 1920s was that fatigue was 'peripheral' - that is to say, the athlete experienced fatigue once their body systems were failing and all the available motor units and fuel reserves had been exhausted (a motor unit is a nerve and the muscle fibres that it fires. Groups of motor units usually work together to contract a muscle). Basically, when the body was exhausted and no longer able to maintain homeostasis - when it hit 'catastrophe' - it shut down.

This seemed like a rational argument, but when scientists began testing it certain aspects didn't add up. For example it was found that at the point of exhaustion the body still had plenty of motor units in reserve, essentially plenty of muscle power left to spare (which explained how athletes were able to marshall last minute spurts of energy when at the end of a race). It was also found that, even when the individual felt completely fatigued, the body was well within safe limits of homeostasis - no organs were being damaged. Other mysteries remained. What could account for the mountaineers Messner and Habeler being able to climb Mount Everest in 1978 without supplemental oxygen, something believed to be impossible? There was also a 'logical' flaw. Why would the body wait until the very last minute, when damage had already been done, to tell the brain that it was exhausted? It would be like a dashboard of a car consisting of nothing more than a set of little lights that flash on to tell you that you've just run out fuel, or to mention the radiator has just overheated, sorry!

Perhaps there was something else regulating our sense of fatigue, a 'central governor' in the nervous system that constantly adjusts the amount of muscle power being used, that paces the body, so that the energy (or 'total metabolic demand') is not all used up. In the words of a key paper on the subject 'the brain paces the body during exercise specifically to ensure that the pre-planned activity is completed without any loss of cellular homeostasis'. It is an example of the 'wisdom of the body'. The central governor subconsciously plans what our thinking minds would not be able to, like a driverless car which gets us safely to our destination.

How does the central governor stop us over-exerting ourselves to the point of damage? It does this mainly by increasing our perception of fatigue. Fatigue is not simply the brain registering exhaustion in our muscles etc; my body is weak, therefore I feel tired. More accurately it is a mental process, an emotion even, the brain telling the body that it is fatigued, not vice versa. It is yet another example of the deep connection between our mind and muscle, how there really is no separation between the two. 

Another example is the phenomenon of post-viral fatigue. This fairly common affliction often manifests after a bout of flu or other infection. Once the runny nose and sore throat has worn off there can be a period of a few weeks in which one feels drained and even depressed. This can last for so long that a purely 'biological' explanation - say the immune system replenishing itself - does not really account for it. It is possible that the central governor has, like a faulty thermostat, become overly sensitive and is now telling the body to do as little as possible, hence the enduring fatigue. The idea of a 'faulty central governor' also provides a convincing explanation of chronic fatigue syndrome - a disabling exhaustion which occurs even at rest and can endure for years with no obvious physical cause.

Exercising once a minor bout of flu or viral illness has passed may therefore be an effective treatment for post-viral fatigue in that it resets our central governor to normal, telling it that it is 'okay' to be physically active again. It seems that we may be able to 'set the dial' on our central governor, to adjust our perception of fatigue. Anybody who has done intense physical training will know how important a 'positive' mental approach is to completing an activity. It may also account for why high intensity interval training (HIIT) can be so effective. By pushing oneself - in short controlled bursts - beyond what the central governor would normally consider 'safe' we gradually increase the threshold of what we feel we can achieve.

The flip-side of this is that, overprotective or otherwise, it pays to listen to the central governor. In our age of being on-the-go constantly (and over the counter remedies, and 'working through it') all too often we do not heed our central governor, our subtle body. We push through the tiredness, in a sense recruiting our survival instinct - our adrenaline etc, to get us through. But eventually we have to pay attention. If we don't, we burn out. It has nothing to do with 'weakness'. In fact the more 'resilient' the individual, often the more catastrophic the crash when it comes, the resources of the body really have all been used up. So, as with all things 'subtle' listening carefully is advised. After all, there are only so many times you can burn out, but there is no limit to how often you can recharge. To finish with a quote from the Tao Te Ching

Men are born soft and supple; dead, they are stiff and hard.

Plants are born tender and pliant; dead, they are brittle and dry.

Thus whoever is stiff and inflexible is a disciple of death.

Whoever is soft and yielding is a disciple of life.

The hard and stiff will be broken.

The soft and supple will prevail.

(Ch. 76)

H James, 2018 

Suggested reading:

- From catastrophe to complexity: a novel model of integrative central neural regulation of effort and fatigue during exercise in humans: summary and conclusions, T Noakes, C Ct and T Lambert, British Journal of Sports Medicine, 2005, Feb 39 (2): 120-124

- The Cure: A journey into the science of mind over body, Jo Marchant, 2016

- Exercise: The miracle cure and the role of the doctor in promoting it, Academy of Medical Royal Colleges, 2015    

- Tao Te Ching, translation by Stephen Mitchell, 1998