From Pre-drinks to Hangover: The Acute Consequences of Ethanol Metabolism

I’ve been very quiet lately. Have some exams to revise but since it’s nearly Christmas time I thought I’d share an old essay I wrote during my post grad days on the consequences of alcohol intake. Not strictly sports medicine i’ll admit but always good to think about in the context of general health. Disclaimer- this is about 6 years old now, so I’m sure there will be updated information out there, but for now I think it makes for an interesting read. Enjoy!


The majority of people are aware of the consequences involved in a night of heavy alcohol consumption. There is the good: the loss of social inhibition, the feelings of empowerment and mild euphoria, an increase in confidence and those epiphany moments you can only achieve after the clock strikes twelve. There is also the bad: the lack of coordination and balance, we lose our ability to rationalise situations, we lose our memories, vomit, perhaps fall unconscious and of course there is the dreaded hangover and all its associated symptoms. But what are the metabolic mechanisms that underlie these consequences?


Alcohol Metabolism


A very small amount of alcohol, about 2-10%, is eliminated from the body in urine or breath (Morgan and Ritson, 2010), the majority must be metabolised to be cleared by the body. Metabolism occurs mainly in the liver, and involves two main steps. The first is catalysed by the enzyme alcohol dehydrogenase (Stryer, 2011).  Here ethanol is oxidized to acetaldehyde (Wrenn et al, 1991), and involves the reduction of NAD+to NADH (McGuire et al, 2006).


CH3CH2OH + NAD+  >  CH3CHO + NADH + H+


Acetaldehyde acts as a general body vasodilator by its activation of release of NO from endothelial cells, and is responsible for the flushing associated with drinking, due to vasodilation of capillaries at the skin surface (Kuhlmann et al, 2004). Acetaldehyde is a toxic substance, and high levels can lead to nausea, headaches and faintness, as well as palpitations (Ashworth and Gerada, 1997). It is interesting that different isoforms of acetaldehyde dehydrogenase can be found across different ethnic groups. It is well documented that many people with Asian origins have a lower tolerance to alcohol consumption, showing a greater flush response after only small amounts of alcohol have been consumed and reporting severe hangover symptoms following a binge. Many studies have looked into these racial differences, including one by Teng (1981) who showed that 50% of Chinese people studied contained a deletion in one of the gene loci encoding acetaldehyde dehydrogenase, which results in an inefficient enzyme being produced.

An anti-alcoholic drug, Antabuse (Disulfram) has been developed that promotes severe alcohol related symptoms and discourages drinking. This inhibits the action of acetaldehyde dehydrogenase leading to a build-up of toxic acetaldehyde (Kristenson, 1995).


The second step is the conversion of acetaldehyde to acetate, by acetaldehyde dehydrogenase (Kraut and Kurtz, 2008)


CH3CHO + NAD+ + H2O   >   CH3COO+NADH + 2H+


These processes combined lead to an increase in NADH levels, a key factor in the development of negative symptoms involved in alcohol consumption.

The NADH:NAD+ratio increases as NAD+is being reduced faster than NADH is oxidised, as NADH oxidation occurs during the metabolism of pyruvate. However, the levels of pyruvate being produced are lowered through the following two mechanisms. NADH feeds back on the glycolysis pathway, see Fig.1, leading to a reduction in the amount of pyruvate produced (Wilson et al, 1981).


EnterFigure 1NADH favours the return reaction of 1,3-Bisphosphoglycerate to Clyceraldehyde 3-phosphate during the Glycolysis pathway, reducing the overall amount of pyruvate produced further along the pathway. (Taken and adapted from Stryer, 2011. Fig. 16.2) 

Secondly, lactic acid is normally converted into pyruvate by the reduction of NAD+, facilitated by the enzyme lactate dehydrogenase in a reversible reaction (Stryer, 2011). Due to the high presence of NADH, the reaction equilibrium shifts to favour lactate production. This leads to less pyruvate available for gluconeogenesis, and so throughout a drinking session, blood sugar levels drop. As the brain is the main consumer of glucose produced in the liver (Kumar and Clark, 2009) most effects are neurological, it is another cause of nausea and vomiting associated with binge drinking. In response to the hypoglycaemia the body craves carbohydrate based foods, hence the desire for fast food experienced by many people at the end of a night out.

As mentioned, there is a decrease in the amount of lactic acid converted to pyruvate, and lactic acid builds up. This can result in lactic acidosis. An increased respiratory rate, to induce respiratory alkalosis, is usually sufficient to counter-act the amount of acidosis that occurs due to an alcohol binge, although venoconstriction can occur, as well as arteriolar vasodilation, resulting in hypotension (Kumar and Clark, 2009), this can have the secondary consequence of tachycardia.

Finally, NADH will also encourage fatty acid synthesis in the liver, leading to accumulation of fatty tissue (Leiber and Schmid, 1960). Short term this has very little effect, and can be reversed by abstaining from alcohol.


Alcohol and the Krebs Cycle


Acetate is converted into acetyl CoA via the enzyme thiokinase. This involves the movement of a phosphate group from ATP, which allows the joining of acetate to coenzyme A (Stryer, 2011).

Acetate + Coenzyme A + ATP    >   acetyl CoA + AMP + PPi


Acetyl CoA would then normally be fed into the Kreb’s cycle, and while this initially happens, the increased NADH levels inhibit the action of two enzymes within the cycle, isocitrate dehydrogenase (converts isocitrate to α-ketoglutarate) and α-ketoglutarate dehydrogenase (converts α-ketoglutarate to succinyl-CoA), see Fig 2.This will halt all reactions within the cycle, leading to a build-up of acetyl CoA, but also α-ketoglutarate, a ketone body. This may result in ketoacidosis, and can be further aggravated by loss of fluids should vomiting be induced due to alcohol (Thomsen et al, 1995). Acute ketoacidosis will rarely cause major problems in a non-alcoholic, but may add to the symptoms of lactic acidosis, such as hypotension and tachycardia.

Figure 2  The Citric Acid Cycle.The enzymes isocitrate dehydrogenase and α-ketoglutarate dehydrogenase (shown by arrows) are inhibited when NADH levels are high. This will slow down the cycle and acetyl CoA will build up, as this normally feeds into the cycle.

The Hangover


The final stages associated with binge drinking are well known, but the mechanisms underlying the hangover are poorly understood, and very little research has been done to resolve this. It is unusual that there should be such an array of symptoms afterethanol and its metabolites have been cleared from the body. There is a long held belief that dehydration accounts for many of the symptoms, although there is conflicting evidence for this. New evidence is emerging for a neurological based cause (discussed below) of some of the symptoms. It is likely a combination of this and dehydration that makes people feel terrible after drinking.


Neurological Effects


Parallel to the effects caused by the metabolism of ethanol, there are also a number of neurological responses, which are the direct effect of ethanol acting on receptors and ion channels within the central nervous system (CNS). The specific effects are variable depending on the region of the CNS involved, but fundamentally, ethanol acts to slow down electrical activity in the brain. For example, Basile et al (1983), showed a decrease in the firing rate of Purkinje cells when exposed to ethanol. This reduces reaction time, cognition and perception, and gives us euphoric sensations. Like all aspects of neurology, studying the effects of ethanol in the brain is a complicated process, and many of these mechanisms are still unknown, for example, the processes underlying memory loss. However some evidence suggests the immune response triggered by ethanol leads to an upregulation of cytokines, which may bind to receptors in the hippocampus, thus preventing these receptors being available for long term potentiation and memory formation (Kim et al, 2003). Continued work into the field is revealing more aspects of the neurological effects and recent work has shown that the sedative effects of alcohol may be due to its action on α5-subunit-containing γ-aminobutyric acid type A receptors in the hippocampus (Martin et al, 2011). The same receptor may also be involved in memory loss. (Nutt et al, 2007) Exactly how this works is still unknown, but a selective inverse agonist for this receptor was shown to improve the memory of subjects after intoxication. These are the first experiments that show simply blocking the activity of certain receptors can offset some of the effects of alcohol, and provide and interesting avenue for further research.

It has also been proposed that the upregulation of cytokines may be responsible for the core symptoms of a hangover, including sickness, fatigue and a lack of interest (Dantzer et al, 1998).  Ethanol and its metabolites have been cleared by this point but the immune response remains, making this a popular theory.


Future Considerations


In an interesting side note, Professor Nutt has carried research into finding alcohol substitutes, based principally around benzodiazepines, which inhibit GABA receptors. This research involves the discovery of a complimentary substance that can be taken later and will remove all trace of the original substance, thus eliminating the hangover. If this hangover-less substance becomes available to the market, in place of ethanol, perhaps future research into the treatment of the hangover will become a mute point.

While the metabolic effects of alcohol are fairly well documented, effective treatments for the dreaded hangover are still largely unavailable. More research into the underlying mechanisms of alcohol breakdown and the effect that metabolites have on the body’s systems should reveal potential therapy targets that may make many of the symptoms of ethanol consumption a thing of the past. This same principal applies to the effect ethanol has on the CNS, although this presents as a serious challenge due to infinite complexity of the human nervous system.




Ashworth M and Gerada C. 1997. ABC of mental health: Addiction and dependence—II: Alcohol. British Medical Journal 315: 358.


Basile A, Hoffer B, Dunwiddie T. 1983. Differential sensitivity of cerebellar Purkinje neurons to ethanol in selectively outbred lines of mice: maintenance in vivoindependent of synaptic transmission. Brain Research 264: 69-78.


Berg JM, Tymoczko JL, Stryer L. 2011. Biochemistry. 7thed. USA: W. H. Freeman and Company.


Dantzer R, BluthéR-M, LayéS, Bret-Dibat J-L, Parnet P, Kelley KW. 2006. Cytokines and sickness behavior. Annals of the New York Academy of Sciences 840: 586-590.


Kim D-J, Kim W, Yoon S-J, Choi B-M, Kim J-S, Go HJ, Kim Y-K, Jaeseung J. 2003. Effects of alcohol hangover on cytokine production in healthy subjects. Alcohol 31: 167-170.


Kraut JA and Kurtz I. 2008. Toxic Alcohol Ingestions: Clinical Features, Diagnosis, and Management.Clinical Journal of the American Society of Nephrology 3: 208-225.


Kristenson H. 1995. How to get the best out of antabuse. Alcohol & Alcoholism 30:775-783.


Kuhlman CRW, Li F, Lüdders DW, Schaefer CA, Most AK, Backenköhler U, Neumann T, Tillmanns H, Waldecker B, Erdogen A, Wiecha J.  2004. Dose-Dependant Activation of Ca+-activated K+Channels by Ethanol Contributes to Improved Endothelial Cell Functions. Alcoholism: Clinical and Experimental Research 28: 1005-1011.


Kumar P and Clark M. 2009. Clinical Medicine. 6thed. Spain: Saunders Elsevier.


Lieber CS and Schmid R. 1960. The Effect of Ethanol on Fatty Acid Metabolism; Stimulation of Hepatic Fatty Acid Synthesis in vitro. Journal of Clinical Investigation 40: 394-399.


Martin LJ, Zurek AA, Bonin RP, Oh GHT, Kim JH, Mount TJ, Orser BA. 2011. The sedative but not memry-blocking properties of ethanol are modulated by α5-subunit-containingγ-aminobutyric acid type A receptors. Behavioural Brain Research 217: 379-385.


McGuire LC, Cruickshank AM, Munro PT. 2006. Alcoholic Ketoacidosis. Emergency Medicine Journal 23: 417-420.


Morgan MY and Ritson EB. 2010. Alcohol and Health. 4thed.London: The Medical Council on Alcohol.


Nutt DJ, Besson M, Wilson SJ, Dawson GR, Lingford-Hughes AR. 2007. Blockade of alcohol’s amnestic activity in humans by an a5 subtype benzodiazepine receptor inverse agonist. Neuropharmacology 53: 810-820.


Teng Y-S. 1981. Human Liver Aldehyde Dehydrogenase in Chinese and Asiatic Indians: Gene Deletion and its Possible Implications in Alcohol Metabolism. Biochemical Genetics 19: 107-114.

Thomsen JL, Felby S, Theilade P, Nielson E. 1995. Alcoholic ketoacidosis as a cause of death in forensic cases. Forensic Science International 75: 163-171.

Wilson NM, Brown PM, Juul SM, Prestwich SA, Sönksen. 1981. Glucose turnover and metabolic and hormonal changes in ethanol-induced hypoglycaemia. British Medical Journal 282: 849-853.


Wrenn KD, Slovis CM, Minion GE, Rutkowski R. 1991. The Syndrome of Alcoholic Ketoacidosis. American Journal of Medicine 91: 119-128.


Physical Activity in UK Children- Should schools be doing more?

Lets start with a disclaimer- I am not a specialist in paediatrics, or public health, and this article is purely an opinion one, albeit one based on fact as much as possible. This article is meant to highlight some of the issues surrounding the childhood obesity problem, and open up avenues for discussion of how they may be solved by more intelligent people than myself.

A recent editorial in the British Journal of Sports Medicine (BJSM) highlighted the need to look at how physical education (PE) was being utilised to meet physical activity (PA) levels amongst school children, as it has been noted over recent years that the current system may be failing in this approach.

The report cited a meta-analysis done a couple of years back in the journal Preventive Medicine, which discussed the limited amount of moderate-vigorous activity that children were participating in at schools both here in the UK and in the USA. I have linked the article below for context and interest however it does require paid access, but fundamentally it showed that current PE lessons were not meeting the recommended moderate-vigorous PA level as recommended by the UK Association of Physical Education (afPE) or the US Centre for Disease Control and Prevention, of being moderately-vigorously active for over 50% of the available teaching time. Further to this afPE recommends children aged 5-18 should engage in at least 60mins of moderate-vigorous PA every day. This is in line with the current Public Health England guideline on physical activity in this age group.

Now the article in BJSM did highlight some of the flaws in the study, including the lack of standardised method of measuring physical activity levels in this population, but the point remained clear. Recommended levels of PA are not being met in schools currently, and this is a problem.

Okay so this doesn’t include PA done outside of the school context, but with children spending a good proportion of their waking hours in school, where young minds develop and good habits, including those around fitness and health, should be formed, I would argue that school is where children should be introduced to healthy habits, and where problems with obesity can begin to be tackled. So why isn’t more PA being done during PE? That is not an easy question to answer, there are likely multiple factors playing a role and I feel a more detailed report into this needs to be carried out.


We are getting fatter. That’s not some revolutionary secret, we all know it’s a problem whether you work in healthcare or not.

This is true for both adults and children; with the latest National Statistics report on obesity (England) showing that 1 in 5 children in year 6 (age 10/11 years) are classified as obese. That seems to be relatively unchanged over the last 10 years, which is somewhat reassuring, however with an estimated 12 million children in the UK, that’s 2.5 million already at risk of going on to develop heart disease, stroke, diabetes, respiratory problems before they’ve even reached childhood. And lets not forget this doesn’t include those classed as overweight, so that number is likely even higher!

Other interesting facts from the National Statistics reports included-

  • Only 16% of children consumed 5 or more portions of fruit and vegetables a day.
  • Children are more likely to be obese living in deprived areas
  • 51% of children who were obese thought they were too heavy compared to their peers

Similarly the Active Healthy Kids – Wales 2018 Report showed that less than 1 in 5 teenagers engaged in the recommended activities levels per week, and only 16% of this same group did any exercise in their free time.


This has to change. We cannot sit by while the next generation walk (or sit) their way into poor health, poor self-esteem and an increased burden on an already burdened health service.

But how do we change this? That is the difficult question, with answers that are more difficult still, but school should be a foundation of learning, both for exams and for life. Here is where healthy habits can, and should, be established in an informed and safe space, and ideally this should be from a young age, where all are encouraged to participate not only in PE lessons, but after school activities, cookery lessons, and health and social education.

Beyond school there should be increased investment in community spaces. Places where physical activity can be encouraged in an informal manner and also in leisure centre, and gyms, where (although controversial) I am an advocate for younger people attending as long as activity is carried out safely and with appropriate supervision.

In the meantime I would argue that if sufficient PA is not being done at school then parents could encourage more to be done at home. The hard truth is this often means parents need to do more PA themselves. Children mimic what they see, so if you want to instil good habits while your children are young, you may need to look at some of your own.

School is not easy. The NSPCC reported an estimated 19000 calls to Childline for bullying related counselling sessions in the 2017/2018 academic year- so numbers of children being bullied are presumably much higher than that. We live in an instant gratification nation with Instagram and other social media platforms telling young people they must look a certain way otherwise they do not belong and this has been linked to a huge rise in mental health, self-esteem and other health problems in recent years. Only by creating an environment where such topics, as well as those around health and fitness, can be discussed openly and without repercussion will things improve- but lets leave the topic of social media to another post.

I do not have all the answers. But lets get the discussion flowing so maybe we can figure them out together, and lets not abandon children to a future of obesity, heart disease and a host of other medical conditions that we all know arise from lack of physical activity.





Reconsidering current objectives for physical activity within physical education


A systematic review and meta-analysis of moderate-to-vigorous physical activity levels in elementary school physical education lessons-


afPE guidelines on Physical Education-


PHE info graphic on current PA activity in children-


Statistics on Obesity, Physical Activity and Diet. England: 2018


Active Healthy Kids- Wales 2018 Report

Concussion in Sport- A Headache of a Problem

Part 2- Management

So we’ve looked at pitch-side assessment of concussion (if you haven’t then see my previous post) and hopefully I’ve got the point across that this can be very difficult, however, I would say the most important take home is that if you are in doubt, remove from play and monitor. Repeat assessments will give you a better idea of any changes, and if you later decide there is no evidence of concussion then no harm done.

If you decide an athlete is showing signs of concussion however, what do you do?


This is the most important step, this allows for further assessment and also eliminates risk of further injury.

Second most important point- any RED FLAGS as outlined in the previous post require an immediate trip to the Emergency Department- don’t try and be a pitch side hero when you don’t even have access to simple x-rays.

The athlete should then be advised to rest to reduce metabolic load on the brain, and is also the initial basis of most head injuries for the exact same reason- in severe head injuries this can be achieved further through sedation on an intensive care unit but that is a whole other subject!

Now how much rest the player should have is still up for debate- the consensus statement suggests that 24-48hours is usually sufficient before a graded rehabilitation plan can be introduced, however I would suggest a caveat to this is that worsening symptoms in this time requires urgent assessment and likely cranial imaging (CT/MRI) to rule out underlying pathology such as a bleed.


Following a rest period, an individualised rehabilitation can be introduced. At this point I feel it is important to outline that symptoms of concussion can persist for up to 2 weeks in adults, and even longer in children, and that continued symptoms are not a contraindication to rehabilitation, however they need to be considered when tailoring rehabilitation to an individual.

With well-structured rehabilitation the majority of athletes can expect to return to play within 10 days, however everybody is different, and no two injuries are ever quite the same. Some patients report symptoms persisting many months after the initial injury, as a general rule often the worse the initial symptoms, the worse the prognosis and road to full recover. It is important not to focus on time to recovery, but rather on response to recoveryin athletes undergoing rehabilitation.

Rehabilitation will always be individualised, depending on the individual, the sport they play and the symptoms experienced as part of their concussion, so it is impossible to outline what a ‘gold-standard’ programme would look like as it simply doesn’t exist, but should be carried out with a team of experienced professionals, and under close supervision.

Some common factors however may include-

  • Sufficient rest period.
  • Detailed analysis of symptoms and deficits sustained, so these can be monitored throughout recovery.
  • Sub-maximal exercise that does not elicit symptoms, slowly built up over the course of recovery.
  • Use of graded return-to-sport (RTS)- more on this later.
  • Targeted physical therapy focussed on any specific injuries sustained.
  • Treatment of associated cognitive/psychological deficits such as depression with specialist input, such as through cognitive behavioural therapy or counselling.

There is a consensus theory that athletes that return to play too early, and without sufficient rehabilitation, may be exposed to additional risk factors that play a role in persistence of cognitive deficit, long after the initial symptoms of concussion have passed. However, there is no gold standard of investigation that can say fro sure how long the roads to full recovery, and so as clinicians we must be vigilant to changes in behaviour, and most importantly seek advice of specialists when needed.


Graded return-to-sport (RTS)

This describes a well-structured, individualised rehabilitation programme that gradually builds up intensity of activity from complete rest to full activity. This is designed to allow sufficient time to recover following concussion and is performed under guidance of a specialist team to allow continued assessment throughout this period. The general rule is that athletes can progress through each stage as long as the level of activity does not elicit any further symptoms- the theory behind this being metabolic load on the brain is built up slowly to allow full recovery to occur- if symptoms occur during any stage then the athlete should return to the previous stage of rehabilitation to allow further recovery time.

Each stage of RTS should be carried out over a minimum of 24 hours, and may take longer depending on the individual.

The following table is taken directly from the consensus statement on concussion in sport and is designed to serve as an example of what the RTS programme could look like. As stated before however, this should be individualised  and undertaken with a team of experts.

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Prevention of Concussion

This is a complex area that is still highly debated, and is not as simple as wearing a helmet, where evidence for their benefit is limited at best. This is a subject that I will return to at a later date… once I’ve had chance to update myself on the latest evidence and guidance!


Final Words

Concussion is a complex and difficult subject. There are no gold standards for diagnosis, no gold standards in assessment, and no gold standards for treatment.

So much work still needs to be done to understands the pathophysiology that underlies this disease process, and how we manage this will undoubtedly change over the years.

My most important take home from all of my ramblings is to have a low threshold of suspicion, always ask ‘could it be concussion?’ and if there is any niggling in those instincts of yours that say it could be then assess off the field of play. Seek advice from experts, those with more experience, and then when you gain that experience yourself, pass it on to others. We still do not have all the answers, so as always, be prepared to change practice if and when the time comes- this is true for all of medicine of course.

No doubt we will come back to the subject of concussion in the future, but in the meantime I still encourage you all to read the full consensus status that I linked to in my previous post.



Not directly mentioned above but here are the current Bart’s NHS Trust and College of Emergency Medicine guidelines on head injury which are a good resource for red flags to look out for-,%202014)%20NOTE%20NICE%20Head%20Injury%20guidance%20was%20updated%20Jan%202014%20(CG176).pdf

Concussion in Sport- A Headache of a Problem

Part 1- Pitch-side assessment

Concussion has been, and remains to this day a hot topic amongst pre-hospital and sports medics. It is a notorious little bugbear in the healthcare system that does not play by the rules of well-established patterns that we often see in medicine. It is difficult to diagnose, which in turn makes it difficult to manage, and in the high pressured situation of pitch side assessment there is the added pressure of getting players back in the field of play, which can often lead to substandard assessment within a very limited timeframe. So I thought this would be a great topic to kick off my new blog with, and one that will no doubt come under serious scrutiny and backlash from the medical profession.

That’s okay, come at me bro. Just kidding, but I will admit that there is much divided opinion on the subject and I am sure that guidance on assessment and management will change dramatically over the net few years.

I am going to split this into two parts. First we will discuss pitch-side assessment, and then we will discuss further investigation and management, as both of these areas require a lot of discussion and I don’t want to bore you all too quickly.


First though let’s start with a bit of background.

It is important to note that concussion does not relate to the head injury itself, that is what it is- a head injury- but instead refers to the change in neurology that occurs alongside.

By definition concussion is temporary unconsciousness, confusion or other neurological symptoms that result from an injury to the head. I would go on to expand this further and say that it is an evolving pathology, with symptoms developing alongside the developing underlying injury, and as such is very difficult to identify and manage, a view that is mirrored by many experts including those of the 5thinternational conference on concussion in sport held in Berlin 20161, which is where much of the information in this post is drawn from. I will link in to this paper and any other sources at the end of the post, and would certainly recommend a read through this at some point.


Why is it a problem?

Concussion is a problem in any impact sport. Most commonly it is associated with rugby, American football, ice hockey and combat sports, but in reality almost any sport has potential for head injury to occur. It is estimated that in every three games played in the NFL, somebody suffers a concussion2, and that after playing 25 matches of rugby union, players are more likely to suffer a concussion than they are not3,4. This is not new data, but it is becoming an increasing concern as we look to the future of those suffering repeated head injury as a result of their sport, the biochemical changes in the brain that these cause and how these lead to increased rates of depression, suicide, types of dementia and other neurocognitive deficits. More research needs to be done but a nice summary of these long-term effects can be found in this paper5. Sufficed to say, we know it’s bad for you.


I am not going to outlined every nuanced detail about concussion management, I am not an expert and to be frank it would be an impossible task- as I have eluded to already there is still so much we don’t understand about the biomechanics of sports related head injuries and the resulting neurological defects these can cause, to say this is the only way to approach these injuries. What I will do though is try and give some practical advice on how to go about assessing and managing suspected concussion at pitch side and beyond.


This is not a one-stop guide- I will always encourage you to question why and do your own research. New evidence may change some, even all of what has been written and as clinicians it is our job to be open minded to new ideas and debunking of old ones, so please by all means if you feel you can give better advice or have new evidence please let me know, we can start a discussion and I will be happy to update with new evidence as we go along.


Recognising Concussion-

This is the hardest part. Imagine it. It’s the 2023 RFC World Cup Final. You are pitch side at the Stade de France in Saint-Denis.  England are 12 points ahead of the All Blacks (I’m dreaming okay, let me have this moment) and fly-half George Ford has just taken a bit of a knock from his counter-part Beauden Barrett as he unsuccessfully attempts to break the defensive line. The crowd are disappointed, so are you, but then you notice George Ford stumble slightly to the left, seemingly off balance. It only lasts a second, and then he’s back in the game, full fighting form. What do you do?


Step 1- recognise a potential concussion.

Great, you’ve done that. George took a knock and you think something isn’t quite right. There is no one-size-fits-all pattern to concussion and although we talk about neurological deficits it can present with a number of clinical signs, or non at all. Often it may be experience that drives the decision for further assessment, but as a first point of call the 2017 Concussion in Sport Group (CISG) point out some clinical features that should be considered in diagnosing a suspected head injury.-

  • Concussion may result from a blow to the head, neck or other part of the body that creates an impulsive force that travels to the brain- so always consider the mechanism of action, for example has a high tackle around the chest driven the head and neck forward at powerful velocity?
  • Neurological symptoms usually have rapid onset and are self-resolving, but as we’ve already said, the pattern can be slow and evolving- have a low threshold for suspicion.
  • Initial signs usually represent a functional abnormality, not a structural one. Therefore classic head imaging will likely not tell you much.
  • Symptoms usually come on and then resolve in a sequential pattern- but this is not always the case.
  • Signs and symptoms do not have another cause e.g. alcohol, drugs, co-morbidities etc.


Step 2- Pitch side assessment.

This should be performed on anybody with suspected concussion- and as a health professional you need to ignore any protests from the player/coach/manager- how much was your indemnity this year? Lets avoid any medico-legal problems shall we. At the end of the day you want to ensure that the player is safe to return to the field of play with no long-term consequences on their health.


Do you have access to video replay? USE IT. Identifying signs of concussion in the heat of play is incredibly difficult, so utilise the tools at your disposal and review video replay if you can.


It goes without saying that in the case of severe injuries you utilise you trauma assessment of the patient, with the classic ABCDE pattern and review of any potentially life-threatening injuries, including spinal cord assessment being performed first. We’ll assume you’ve done that.


Red Flags-

I won’t go into the details of how to carry out a trauma assessment, that can be learnt on a number of expensive courses I am sure many of you will have done, but it is always important to cover red flags in head injury that anyone can recognise, and should prompt immediate removal of play and in most cases transfer to hospital. These are taken direct from CISG guidelines as well as from NICE guidelines6, but modified to be specific to sport, and are a good little summary to remember-

  • Unconsciousness or lack of full consciousness, even if the person has now recovered.
  • Seizure, vomiting or increasing headache.
  • C-spine tenderness
  • Evidence of CSF leak- clear fluid running from the ears or nose.
  • Bleeding from one or both ears.
  • Bruising behind one or both ears.
  • Any signs of skull damage or a penetrating head injury.
  • The injury was caused by a forceful blow to the head at speed- consider the mechanism of action, and in the context of sport being played.
  • The person has had previous brain surgery.
  • The person has had previous problems with uncontrollable bleeding or a blood clotting disorder, or is taking a drug that may cause bleeding problems (for example, warfarin).
  • Increasingly restless, agitated or combative


Assuming there are no immediate concerns now comes the tricky part- concussion assessment.



There are many tools available for assessing likelihood of concussion at the pitch side. The Sport Concussion Assessment Tool (SCAT)7is standardised and is the one recommended by the CISG- caveat to this is that they designed it so there may well be a bias in its use.

You may find another tool that works better for you but the important thing to note is that these tools should never be used as a single tool to identify concussion. There is no single test. It is a clinical decision.

Having said that it can be a very useful aid to frame your clinical assessment around, so it is well worth a read in advance. Find a link to the full SCAT5 below.

Important points to consider are-

  • It is recommended for use in anyone aged 13 or older. In younger children there is a Child SCAT, which I will not cover in this post.
  • Healthcare professionals with appropriate training only should use it.
  • It can be used in advance of play to create a baseline for your players- this is not essential, and there is debatable evidence on how effective this is, however I personally like to do this as it also gives me chance to get to know the player and how they answer questions, which can be useful for identifying a change.



The SCAT is divided into on-field and off-field assessment.

The on field assessment includes GCS score, the Maddock’s questions (these are similar to an abbreviated mental test score and are designed to assess immediate change in cognition and memory deficit), as well as assessment of C-spine and red flags.

At this point if suspicion of concussion continues then further assessment should be carried out off pitch, in a safe, quiet environment. The SCAT divides this assessment into 6 parts-

  1. Athlete’s Background
  2. Symptom Evaluation
  3. Cognitive Screening
  4. Neurological Screening
  5. Delayed Recall
  6. Clinical Decision


There is a tonne of useful advice on the SCAT, which is linked below, on how to carry out this assessment and I would recommend having a read through this.

Concussion evolves, I cannot emphasise this enough, and so serial assessments may need to be carried out and it is essential that the player is not left unattended during this period.


The final point I need to emphasise in this overly long post is that any player who you suspect has sustained a concussion should not be allowed to return to the field of play. They require further assessment, investigation and rest- this reduces metabolic load of the brain and allows the process of recovery to begin. Rehabilitation can then begin, but we will cover that in the next post.



















Insights into Sport Medicine

Thanks for joining me!

Let’s start by way of introductions. I am a junior doctor based in Manchester, UK. I graduated from Cardiff University a few years back and I am now working towards a career in Sport and Exercise Medicine (SEM). It’s not the first career people think of in medicine, and people are always a bit surprised when I say that’s what I want to do. Many don’t even know that it is a branch of medicine, even some of my own colleagues! I quite like surprising people though, it usually leads to an interesting conversation after and people are always keen to tell me about their painful knee or sore shoulder when they find out what I want to do. I don’t mind, but there is more to a career in SEM than just musculoskeletal injuries.

Yes MSK problems are a big part of it, and pitch side (or track side in my case- I love athletics!) management of injuries is an essential skill of any sports physician, but there is so much more than just managing a twisted ankle- management of major trauma, head injuries, cardiac problems, respiratory problems… to name just a few. We carry out invasive procedures including intubation, ventilation and central venous access. We deploy a whole host of pharmaceuticals to manage the acutely unwell and the patient in severe pain. We offer coaching and advice in areas of performance and research. Pitchside is only one part of it, there are a few more avenues a future SEM doctor can venture down.

Rehabilitation. Occupational health. Respiratory conditions in sport. Cardiac conditions in sport. Endocrine conditions in sport. Drug and IPED misuse. Advisory roles for IOC and other regulating bodies. Research and academic roles.

Not to mention the performance side of things- just think about the number of different events you see in the Olympics every 4 years- at Rio 2016 Great Britain took home 67 medals. Behind each of those medals is an entire host of specialists, including doctors, trying to get the best performance possible out of the athletes that win them. As to what that involves, well I often compare SEM to intensive care medicine, but while the intensivist is trying to get a patient with incredibly poor physiology to normal physiology and function, a SEM doctors aims to take someone with normal physiology to supranormal- in other words, we literally create superheroes. Just sayin.

My interest? All of the above. I am still learning so much about my future as a doctor and I haven’t fully decided where that might take me. That may change soon and I’ll be sure to let you know if it does… or you may just start to see my blog posts favour one area of SEM over another!

Anyway- this blog aims to offer up to date information for clinicians and others working in this field about the latest research and practical applications of practising SEM. We will look at new papers, consensus decisions, offer revision aids and basically anything else I can think of related to this field.

Why am I doing this? The amount of training we get at medical school about sport and exercise medicine is pretty much zero. Nada. Zilch. So this blog will (hopefully) go some way to fill that gap in knowledge and maybe even be a little bit interesting!

I am not an expert. This is as much a learning experience for me as it is for anybody else and I openly encourage differing points of view, debate, contradictions and generally just telling me I am wrong if I am. Educate me when I am. Thats the only way we learn and grow. Lets just keep it friendly yeah?


We look for medicine to be an orderly field of knowledge and procedure. But it is not. It is an imperfect science, an enterprise of constantly changing knowledge, uncertain information, fallible individuals, and at the same time lives on the line. There is science in what we do, yes, but also habit, intuition, and sometimes plain old guessing. The gap between what we know and what we aim for persists. And this gap complicates everything we do. — Atul Gawande