Wednesday, 27 February 2013


Legend has is that a Greek soldier by the name of Pheidippides, ran from the plains of Marathon to Athens, to announce that the Greeks had just defeated the Persians, in 490 BC.  The distance he ran was 42.2 kilometers, which has then become the official distance of a ‘marathon’.  Legend also has it that after announcing the victory, he collapsed and died.  2500 years later on February 24, 2013 a brave citizen of Bombay ran the half marathon in Thane, and at the end of the race he proudly collected his medal.  After receiving his coveted prize, like Pheidippides, he too collapsed and died, despite intense efforts to revive him by the doctors present there.
Historians contested this version of Pheidippides, and in fact later discovered that he had run well over 450 km, over a ten day spell and was instrumental in saving the battle for the Greeks.  Unfortunately, for our Bombay Braveheart (I am not naming him, in respect for privacy), and his family his death is undisputed, and I extend my deepest sympathies to his family and friends.

As is to be expected, this running death has created grave concern within the running fraternity of Mumbai, of which I consider myself an integral part (both, as a runner and as the Medical Director of the Standard Chartered Mumbai Marathon).  In the media, and in the running community I have encountered polarized views on the risks of long distance running.  One view is that exercise in general, and running in particular is extremely healthy, and therefore cannot be harmful by any means.  The opposite view is that running is dangerous and if one wants to exercise, nothing beats a leisurely walk.  In my opinion, neither of these views is absolutely true, since this is a complex topic and needs a deeper understanding rather than knee-jerk one-liners.  The purpose of this article is to try and shed some more light on the risk associated with marathon running.

Before we begin, I would like to clarify that this article is not about the benefits and risk of exercise in general.  The health benefits of exercise have been unequivocally established, and these benefits very clearly outweigh the risks.  Also, this article deals with running  half and full marathons, and not distances beyond that.  There is new literature emerging on the cardiovascular effects of ultramarathons, which can be discussed separately.


In 2012, a study was published in the New England Journal of Medicine, titled ‘Cardiac Arrest during Long-Distance Running Races’. This looked at the incidence of cardiac arrests in marathon and half-marathon races in the United States from 2000 to 2010, and included 10.9 million runners.  In that entire period there were 59 sudden cardiac arrests, of which 42 were fatal.
Sudden cardiac arrest occurs when the heart suddenly and unexpectedly stops beating. When this happens, blood flow to the brain and other vital organs stops, and can lead to death if not treated within minutes.  In fact, this year at the SCMM marathon we had a sudden cardiac arrest, and due to a combination of luck and medical preparedness we were able to save the runner (for more on that, read here:

The following is the information we learned from the Cardiac Arrest study:

  1. Cardiovascular disease accounted for the majority of these cardiac arrests and deaths
  2. The incidence of arrests was significantly higher during full-marathons than half-marathons, and was higher among men than women
  3. The incidence rate of cardiac arrest during half and full marathons was 1 per 184,00 runners
  4. The incidence rate of death during half and full marathons was 1 per 259,000 runners
  5. The commonest cause of death was hypertrophic cardiomyopathy

According to official figures, about 10 deaths take place on the Mumbai suburban railway network each day, and approximately 7 million commuters travel each day. This translates into 1 death per 700,000 commuters. In other words, the risk of dying during marathon running is a little more than double that of taking a ride on the Mumbai local trains!  I know this is not a fair or scientific comparison, and I do not mean to trivialize even a single death, but the idea is to put the risk in perspective, which in absolute terms is very low.



The two most common causes of death found during this study, as well as others looking at exercise and acute cardiovascular events were:

  1. Hypertrophic cardiomyopathy
  2. Atherosclerotic coronary artery diseases (blockages in the arteries)

Hypertrophic cardiomyopathy (HCM) has been defined as a primary disease of the myocardium (the muscle of the heart) in which a portion of the myocardium is hypertrophied (thickened) without any obvious cause (source: Wikipedia).
It has been well established that among young individuals, less than 30 years of age, HCM and other birth related (congenital) abnormalities are the main cause of cardiovascular events.

It was also thought that in athletes over the age of 30, atherosclerotic coronary artery disease (which is just the scientific way of saying ‘blockages in the heart arteries’) is the most frequent cause of cardiac arrest and death.  Vigorous exertion was thought to lead to rupture of the blockage, leading to clot formation, which leads to an abnormal heart rhythm knows as ventricular fibrillation and ultimately death.

The surprising finding in the New England study was that HCM was also the leading cause of death in the population studied during the ten years of marathon running, including the older runners.  Several of the deaths were due to a combination of HCM and blockages in the arteries.


Besides the cardiovascular causes, hyponatremia (low sodium level in the blood), and hyperthermia accounted for a total of about 10 percent of the deaths.  These remain important concerns during long distance running but are not common causes of death.


This is clearly the most important question at the end of it all.  In my opinion, risk can be reduced by taking care of the following:

  1. Pre-participation health check
  2. Paying heed to warning signs
  3. Sensible and appropriate training programs
  4. Medical facilities available during races

Pre-Participation health check:

Before you read any further, it is important to acknowledge that the human body is an extremely complex organism.  There is no definite testing protocol which can completely rule out risk, which is why you occasionally have the scenario of someone suffering an attack, even though they recently passed their medical evaluation with flying colours. Having said that, these are the tests I recommend, and the reason for each:

  1. ECG: this is certainly not a perfect test, but is a great starting point to give a basic indication of your heart function. It’s a great test to pick up HCM
  2. Fasting sugar, lipid profile, blood pressure, body mass index and weight circumference: all of these will give an indication of your ‘cardiac risk profile’.
  3. Stress test: one can debate the necessity of a stress test, but I would recommend it for two reasons.  It’s a great indicator of your cardiovascular fitness, if nothing else and may indicate the presence of blockages in your arteries.  One can criticize it for two reasons too: blockages show up on the stress test only when they reach a certain size and are ‘obstructive’ to the flow of blood. Often, there are smaller plaques which are the ones that actually rupture and cause the attack. Also, stress tests often show up ‘false positive’ tests, wherein no abnormality exists even though the test is abnormal (for some strange reason, doctors call it ‘positive’ when it is abnormal).  Let the physician conducting the test know that you are a marathon runner and to allow you to carry out the test till you reach maximal fatigue.
  4. 2 D- echo: this is a great test to assess  heart valve functioning, and the pumping capacity of your heart muscles. It’s also a great test to rule out HCM. It is relatively expensive, and if you are younger and asymptomatic I guess it would be fine to just do a simple ECG.

The most important part of the evaluation is to consult with a physician who ‘understands’ exercise and the kind of program you hope to embark upon.  In addition to the above tests, your medical and family history is vital.  Data from individual tests do not have as much meaning as the combined risk profile.

Warning Signs:

Several studies have shown that individuals who experienced cardiac events during exercise, often had mild warning signs and symptoms, which they or their physician chose to ignore.  The most common of these, which occurred a week before their arrest were (as reported by friends and families):

  1. Chest pain
  2. Increasing fatigue
  3. Indigestion / heartburn /gastrointestinal symptoms
  4. Excessive breathlessness
  5. Ear or neck pain

Appropriate training programs:

All exercise programs should be progressed gradually.  Most arrests and deaths occur in individuals who participate without adequate preparation or those who ramp up their training exponentially.  At the end of vigorous physical exertion it is important to cool down appropriately (something which most of us, including myself do not do), since reduced blood supply to the heart may be exacerbated by abrupt cessation of activity.  This is the reason that runners often collapse immediately after finishing an intense race.

Medical facilities on race day:

It goes without saying that adequate medical facilities should be available during long distance runs, especially those exceeding 10 km.  In addition to medical facilities, I personally feel that every runner should take it upon himself or herself to learn the technique of CPR (cardiopulmonary resuscitation). In the event of a cardiac arrest, good CPR can be life-saving.


Long distance running can be a safe and enjoyable sport with considerable health benefits.  There is a small amount of risk involved which can be kept to a  minimum by making sure you undergo a ‘running-specific’ health check, train sensibly and pay heed to warning signs and symptoms should they occur.


1. Cardiac Arrest Duing Long-distance Running Races. Kim et al, NEJM 2012;366:130-140
2. Exercise and Acute Cardiovascular Events: American Heart Association Scientific Statement: Circulation 2007;115:2358-2368


  1. Very informative write-up, thank you.

    Your comments on the following would be appreciated.

    A serious problem for runners is that most doctors they go to for ECG/Echo/Stress tests etc are unfamiliar with specific conditions that may develop in runners which lead to false tests (refer revised recommendation by a Stanford team, citation 1 & 2 below) -
    - For example the left ventricle of well trained edurance atheletes is larger & thicker.
    - In a lot of long distance runners an ECG shows up arrthymia however a stress test/echo test is normal (I have had false ECG tests leading to normal stress or echo stress tests twice). Such arrthymias are now considered normal in most endurance atheletes



    1. Dear Sandeep,
      You bring up interesting and valid points. The interpretation of a stress ECG is as much an art as a science, and therefore I suggested consulting with a doctor who is familiar with running.
      Often people have mild arrhythmias at rest, which 'go away' during exercise, which is a good sign. As regards, runners having arrhythmias there is some (not so good) data emerging that putting in excessive running miles (such as for ultras), may lead to conditions which may promote these rhythm disturbances. I will write on that separately.

  2. Very informative and useful blog not only for runners but also for entire population. I also feel that information regarding certain must food items (necessary micro nutrients) is equally essential. All athletes (which includes entire running community) must understand necessity of consuming these important food items. And this should be part of one's lifestyle. Consumption of fruits, Dryfruits like Walnut/Almonds, Figs, Dates, Flax seeds, (Different color) Salads is almost must to maintain better health to be able to keep Cardiac issues away.

    1. Dear Rohit,
      I agree with your comments. In fact, this week in the New England Journal of Medicine, was an excellent article on diet and heart health. Here is a link to the article, posted on our cardiac rehab facebook page for your reference.

    2. i am regular marathon runner i would like to undergo all the test that you have mentioned,i am staying in khar in mumbai...the Bombay Braveheart u mentioned above completed just 1 minute before me...saw him going down...
      would like to be sure about myself.hence all these test...
      pls suggest an hospital or medical centre where i can undergo all these medical tests

    3. Sushil,
      You can undergo these tests at any good medical center. It's important to have the results interpreted by a doctor, with a knowledge of exercise and running. Asian Heart Institute is one such option.

  3. Very good article...there is one practice I follow which is to starting exercising only after 45 minutes after you wake my view our body is a bio-mechanical machine and it needs its own time to start (switching on all the vital systems)...just like you start a diesel vehicle and wait for a couple of minutes before pushing the pedal...
    Don't have any links to prove this theory but it does not harm anyway following it...I always tell myself and others..."Use your body don't abuse it"...

  4. Sunil,
    Thanks for your comment. What you say is interesting, and I would follow it too, but sleep is very precious :) so on my long morning runs, I tend not to wait that long. Actually, come to think about it, since I drive to NCPA to start, it does end up being about 35 min from the time I wake up.

  5. Thanks for a detailed account and checks one has to undertake as a precautionary measure. But how often they need to be done? There are plenty of runners who would be either training every day and many participating in races all the time. I think it's difficult to suggest any particular time period.

    1. Siri,
      I would say that the 'complete check' could be done once in three years, assuming the results are fine. If there are some abnormal results, then appropriate and timely follow-up needs to be done.

  6. Nice informative article. What is your opinion on myocardial fibrosis in long distance runners?
    Will it be a worthwhile practice to do a Cardiac SPECT for periodic evaluation in Marathoners?

    1. Muthukrishnan,
      The topic of myocardial fibrosis is very relevant though relatively new. Personally, I would not recommend it as a routine test unless you are into very high mileage, such as training for several ultras (50 km plus) in a year. I am planning to write a separate blog on this subject in the near future. Stay tuned.

  7. there is more to cardiac events in long distance runners than just their hearts.

    1. after a long run - lasting over an hour or two, sudden stopping and then standing in one place is a sure recipe for a vasovagal attack. that can easily progress to cardiac arrest, if not treated properly in time.

    how often have we seen finishers standing in line to enter the finish area, then standing in line to collect medal, refreshments and such? too often for comfort.

    2. inadequate and improper hydration - and electrolyte replenishment will play havoc with your heart and its rhythm. too much water, too little salt and you land in hyponatremia. which will make you collapse. too little water, dehydration, you will end up in shock and collapse.

    3. just as it is necessary to train oneself to run, it is necessary to train to hydrate and supplement electrolytes. every person is different. some sweat more, some less. some have to drink more water, some don't. some have trained in colder areas, while the event is happening in a warm place. weather may suddenly warm up. if you sweat more, you need more salt. and don't forget potassium too. those oranges and bananas are there for a purpose.

    4.don't rush to enter the finish area. hang on. don't rush to collect the medal. volunteers will be around for a long time afterwards. walk about, drink more water, eat something. relax. then do all the above. you have NOT won the event. your time has been CLOCKED. there is no HURRY to collect your stuff.stretch. watch other runners finishing. wave to spectators. try to look happy that you finished. people ARE looking to you with admiration and respect. enjoy that for few minutes. then go the medal counter.

    5. any amount of pre race checkup and investigation will not help you if you don't take care of your hydration/eletcrolytes. and stand in a line immediately after finishing.

    pre-race checkups and being found fit; are like airworthiness of an aircraft. if the plane is not fit to fly, pilot should not attempt to fly. once the plane takes off, it is for the pilot to manage the flying, refuelling; and see that he lands it in one piece.

    don't worry guys. don't rush for an EKG and blood check if this was your second or third marathon. for first-timers, checkups are fine.

    keep running.

    vivek gharpure

    1. Vivek,
      I agree with most of your points, except for the last bit.
      If you have not been checked and this is your third or fourth (or more) race, that certainly does not mean that you should not be checked. As far as I am aware the poor runner who died had done a few half marathons earlier. This is not to suggest that even a check up is a 100 percent guarantee that an event will not take place, but it will serve to reduce the risk.
      Also, hyponatremia and hyperthermia are important, but at least in the study (which really was very extensive- 11 million runners), they accounted for less than ten percent of deaths- so their importance is RELATIVELY far lesser than cardiac issues, as far as potential death is concerned.
      As regards your first point, of suddenly stopping after running - that is absolutely true, but not for the reason you mentioned. Its more to do with reduced cardiac perfusion.

  8. Dear Ashish,
    Excellent overview covering relevant details and thanks for allaying anxiety among running fraternity.
    Just want few clarification ,whether using heart rate monitor during running will give some prior indication about cardiac arrest ? Is there any symptom or indication to know about hyponatremia ?

    Dr Shirish Kataria

    1. Thanks Shirish,

      I don't think using a heart rate monitor will necessarily give you an indication about a cardiac arrest, but a heart rate monitor is a very useful tool for safety and good training. It 'might' give an indication that something is wrong, if the heart rate fluctuates wildly without reason (for example hitting 95 percent of max in a seasoned runner, at a very low workload-indicating something is wrong).
      Often there are no symptoms of hyponatremia, or they may be quite vague, such as nausea, muscle cramps, slurred speech (which can often be mistaken for dehydration, for which you will give water, with negative consequences). Here are links to two good articles on the subject.

  9. Without doubt, it is a very tragic end to a brave effort. I would like to stress on the importance for runners to be playing other sport like tennis, squash, etc or swimming or cycling to boost their overall fitness due to the varied movements and muscles that come into play.

    By doing so, even on days when you do not run, your heart rate is up for that period of play/exercise. One gets more opportunity to understand the body.

    Also, while running I feel it is so so very important to focus on one's ownself and not watch what others are doing and trying to match somebody else's pace. One last thing...Every runner is unique, every run is unique. So, even if you have planned on a 15K today, but don't feel good after 5K, no harm stopping and relaxing. There's always one more run tomorrow.

    Keep running,

    1. Anand,
      Thanks for the sound advice. However, if your goal is to run a marathon, then the cross training (especially in the last 16 weeks or so), should be limited to once a week.

  10. I am 43 years male. I have done 9 half marathons and 3 full marathons besides average 45 Km weekly running practice through out the year for more than 5 years.
    During recent Mawana Marathon on 17 Feb 2013, I was running at speed about 11 km/hr which is faster than my SCMM13 speed of 10.2 Km/hr with timing of 4 hrs 09 mins. At 38 km mark, I felt fatigued, walked about half a km, then sat on road side for 4-5 minutes, then lied down and then I was unconcious for about 10 minutes. An ambulance carried me to hospital, where I had a little I/V perhaps normal saline, drank electrolytes and was up after 10 minutes. The reasons for above incidence is perhaps lack of energy and salts intake. But fainting could be very dangerous in case medical help is not available soon.
    The important point I want to make is that, in long distance run, just rest is not sufficient for recovery. I would suggest long distance runner should carry electrolytes / carbs (like GU) with him while running. Even after finishing your run, you need lot of electrolytes, energy, salts and water for recovery.
    Dr. Aashish, kindly comment.

    1. I agree with your comments. Without doubt, an appropriate rehydration and nutrition strategy during a marathon is crucial. As you correctly point out, this needs to continue even after the run.
      If you were unconscious for ten minutes I would be very concerned (are you sure it was ten minutes? That's a very long time), and get a thorough evaluation done.

    2. Thanks.
      I took 3 biscuits and 1 banana 1 hr before race. 500 ml gatorade at start, 1 GU at 10km, 500ml gatorade at 25km. Nothing after that. I did not have cramps. Did not feel thirst. Doctor checked Blood Sugar 99. Can you make out some probable diagnose based on above information?

  11. of course you know best. if checkups do not prevent an event, by what does percentage points does it reduce the risk of an event, if the check up was normal? is there any analysis on that? i could not find any.; says risk of cardiac events is low during marathons and beginners should undergo a checkup.

    "We've had 32 years of London Marathons. More than 750,000 runners. We've had eight deaths which equates to about one in 94,000 runners. That's about one death in two million running miles. Death rates are low."

    thank you

    p.s. will be obliged if a study showing reduced risk after checkups is found in literature.

    1. Vivek,
      Death rates are definitely low, and that's great news for all of us. However, for the one person or family that does experience it, it is devastating. It's very hard to say how much it may reduce the risk in a given individual, but here is some interesting data. Italy is the world leader in screening their athletes taking part at a high level, in school, college and upwards, and their pre-participation screening found- and here i quote from an American Heart Association Statement:
      "They report a time-trend analysis showing a substantial decline (almost 90%) in the annual incidence of sudden cardiovascular death in competitive athletes for the Veneto region of northeastern Italy".
      For your reference, here is the citation for the Italian study:
      Corrado et al. Trends in sudden cardiovascular death in young competitive athletes after implementation of a preparticipation screening program. JAMA; 2006;296:1593-1601.

  12. Hi Ashish,

    I would like to mention one point which most runners tend to forget: one must run marathons at a pace where one is able to carry on a conversation with partner without getting breathless. Most, in order to improve on their personal best, focus on speed at which they are clearly uncomfortable. this only increases the burden on the heart. Your comments, please!

  13. Dean,
    I agree with your point. However, at the same time, lets face it, most runners are competitive (even if it's only with themselves), and would like to achieve a personal best.
    Here is where they need to apply common sense and a good training program. Personal best goals need to be realistic and backed up with the correct training.(refer to one of my blogs in 2011, where i talk about 'how to run a half marathon in under 1 hr 45 min).
    Pushing yourself a 'little beyond' your comfort zone is fine, but there is a thin line between a little beyond and too far beyond.

  14. Interesting to read above thread. Basically we as runners have forgotten that we started running to keep fit and enjoy happy life with family, friends and be successful in career and society as a fit person mentally and physically. However once the taste of success is experienced we want to cling on to it in spite of harm to us. We have to listen to our body first and then to friends while running. Everyone's training may be same but the fitness level across muscles, bones, heart rate, metabolism, salt spend and recovery rate is different for each of us. What works for one may not work for another. Therefore run as long as you enjoy and focus on each parameter to strengthen that is required for successful marathon like muscle's ability to store glycogen and replenish, bone density, heart ability to endure long runs, salt utlisation and ratio etc. If one doesn't feel any pain or tiredness after every long run, that is indication that he or she is fit and could step up miles. If you drop down in fitness, start all over from small miles and stay at peak. I have run 10 marathons and learned these with practical expereince and now also I run marathons but it has become very spiritual without need to prove to anyone or competitive..just enjoy my run for the sake of pleasure of running.

    1. Sridhar,

      Thanks for your post- I agree with all of your points and I think its great advice.

  15. "Legend has is that a Greek soldier by the name of Pheidippides, ran from the plains of Marathon to Athens, to announce that the Greeks had just defeated the Persians, in 490 BC. The distance he ran was 42.2 kilometers, which has then become the official distance of a ‘marathon’. Legend also has it that after announcing the victory, he collapsed and died."

    Sorry but the opening paragraph is laden with erroneous information. The distance that Pheidippides ran was not 42.2 kilometres; that distance became the standard marathon distance after the London Olympics in 1908. Prior to that time the standard distance was 25 miles, the distance from Marathon to Athens.
    That Pheidippides died after such a run is also a myth, never recorded at the time and only surfacing hundreds of years after the event by a writer all to ready to embellish the truth.

    1. Matt,
      If you read my second paragraph I have written about the fact that this 'legend' has been disputed or proved wrong by historians, and have also written about what is now accepted as historically accurate.
      In any case, this article is not at all about Pheidippides- its about long distance running and the risk of death.

  16. people tend not to listen to their bodies...if the body says it wants to rest but you go and run then this is bound to happen......

    1. Shalil,

      I agree that one needs to 'listen to their bodies', but frankly what does that really mean? In extreme cases, where you totally breakdown and take long recovery times between runs, then its obvious you are pushing too hard. But what about the regular aches and pains and fatigue that most runners experience? Sometimes, it's very hard to draw that line, and it may take individuals several years of running to fully appreciate it.

  17. Being a Doctor , and having run 8 HMs and a FM (5 hrs 1 min), I am of the
    view that everything is good for the human body ONLY in moderation and
    variety. The same applies to 'running miles' as well. Just as human diet
    should be balanced and varied to obtain all the nutrients, same is with should be moderate and varied to benefit the entire
    musculoskeletal system. No sense in running junk miles week after week in
    the off season, when attention should be paid to maintenance and building up
    a solid base. The off season should be devoted to other forms of cross
    training and building up on core strength and flexibility. This is the best
    way to avoid abusing the body and future known and unknown medical problems.

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