When you’re in the zone, you’re in the zone and it’s pretty easy to ignore what your body is trying to tell you. You want a sub-[insert target number of hours here] time and nothing is going to get in your way, right? Well, we at London Doctors Clinic have scoured the world of running forums and blogs to bring you some of the grossest things that can happen to your body when you’re running a marathon (we also asked our private doctors the best ways to deal with them)! Just a little warning, if you’re easily grossed out, this blog post is not for you – sorry! 


1. Smelling 

We’ll start with a tame one, just to ease you in. When we exercise, our hearts pump blood from our muscles to our skin and we sweat – this cools our bodies down and prevents us from overheating. It is not actually the sweat that leads to body odour; rather, it is the acid that is produced when bacteria break down this sweat. Fun fact – because of a mutation called ABCC11, most Koreans do not get body odour! Body odour, combined with the fact that we have to battle outside elements (wind, rain, heat etc.), can lead to quite a stench. And this doesn’t even go into detail about what happens when we take our shoes off…

What the doctor says:

"There is nothing wrong with sweating, especially while running a marathon! In fact, it would be more concerning if you didn’t sweat while running a marathon.

That said, some people do sweat more than usual, due to a condition known as hyperhidrosis. Although usually not harmful, this condition can have a significant affect on the confidence of the sufferer. If conservative management (like loose clothing, avoiding triggers, strong antiperspirants) is insufficient in, sometimes Botox can be used to reduce excess sweating.

Conversely, some people don’t sweat enough, due to a condition known as anhidrosis or hypohidrosis. Although for some, the prospect of a sweat-free life may seem glorious, this is in fact the more dangerous of the two sweat-related conditions, as the body struggles to cool itself – meaning it can overheat. As mentioned above, sweat performs an important function in helping to lower our body temperature when it starts to creep up, as it's evaporation off the skin has a cooling effect, bringing the body’s core temperature back down to the optimum range. That’s why running clothes are designed to ‘air it all out’…

As for the smell, there are a vast range of antiperspirants you can buy from your local chemist or supermarket that may help mask any odours. Interestingly, there is a condition whereby sufferers’ body odour smells unusually like fish – known as trimethylaminuria or “Fish Odour Syndrome”. But if you hadn’t noticed this by race day, you either don’t have it or you really haven’t been training enough."


2. Blisters 

Never underestimate the power of the blister! One of these bad boys on the back of your foot or between your toes and your run can go from pleasant, to uncomfortable, to downright excruciating. Blisters occur when our skin becomes damaged by friction (for example, between our skin and our socks) and may be more likely to occur when there is excessive moisture (i.e. sweat!).

What the doctor says:

"Make sure you invest in a good pair of running trainers (and socks too), and ensure you give them a good wearing-in. Marathon day is not a good day to whip out your new box-fresh shoes.

If you’re prone to blisters, you could try some good quality blister-patch plasters to protect the known at-risk areas, to reduce your chance of developing blisters on race day.

If, despite such prevention methods, you do develop a dreaded blister, try to resist the temptation to pop it, as broken skin is at a higher risk of developing infection (especially in the bacterial and fungal breeding ground that is your running shoes!)."



Your trainers are a breeding ground for bacteria and fungi. Read more about Athlete's Foot!


While we’re on the topic of feet, a lot of runners complain about black toenails, and some even prefer not to wear open toe shoes because of them. So what causes ‘jogger's toe’? Well, it is the bruising under the nail as a result of the toe hitting against the front of the shoe (also known as repetitive trauma). 

What the doctor says

"To reduce trauma to the nail, try making sure it’s cut as short as is comfortable. Longer nails will push against the front of your running shoe and further provoke such trauma. Try to achieve that fine balance between your shoes being loose enough to prevent trauma, and tight enough to properly support your foot.

Watch out for other causes of black toenails, such as fungal infections. If in doubt, ask your doctor for a proper diagnosis and management advice."


4. Snot

This was a new one for us. According to a number of sources, the 'snot rocket' is famous move (can we call it that?) in running circles. To carry out said move, Runner’s World advises that you first mark off a 'blast radius' (of around 3 to 4 feet). You must then, they suggest, breath in through the mouth, push your finger firmly against one nostril, purse your lips, move your head in the direction of the open nostril and exhale through your nose. But beware, if you mess this one up/ you’re not co-ordinated enough, you can be covered in your own snot – which isn’t ideal!

What the doctor says

"Catching a cold just before race-day is just plain bad luck, and there’s little you can do to minimise the consequences. Most colds are due to viruses, so antibiotics will be of no use.

Unfortunately, when it comes to the issue of snot, there’s little advice a doctor can provide! But by all means, feel free to try the above technique if you’re feeling brave enough…

With regards to running while suffering from a respiratory infection, runners often go by the following rule of thumb: colds affecting the throat and above are generally okay to run with, but if your colds affects below the neck (such as with bronchitis or ‘chesty’ coughs), then it is probably best not to run until you are feeling better.

That said, any infection – viral or bacterial – makes your body work overtime and your immune system run on overdrive, fighting the pathogen responsible for your symptoms. Do you know what else puts your body to work? Running marathons! Therefore, the “marathon + cold” combination is essentially a double-whammy of shocks to the body, and is discouraged!"


5. Chafing

... Is the answer to the age-old question “why do men’s nipples sometimes bleed when they run?”. Areas also affected include thighs, armpits, the groin, bra straps – basically, any area where skin rubs against skin or fabric and causes no end of irritation.

What the doctor says

"Make sure you’re wearing a tried and tested running outfit, when it comes to the big race. And if you do insist on wearing a Mickey Mouse costume, or a papier mâché shark outfit as part of your fundraising fancy-dress attire, make sure you take it for a decent test-run before race-day. That way, you can identify areas that may chafe and can prepare further protection for these at-risk areas.

As for nipples – some people swear by Vaseline, others wear plasters. Again, it’s best to try a few of these methods in advance, and work out which works best for you. Then make sure you arrive to the race prepared for the worst, with Vaseline and spare plasters to hand!"


6. Vomiting 

Overexertion, eating too much of the wrong thing before a run, overexcitement – there are numerous reasons for vomiting while/ after the race. 

What the doctor says

"Running a marathon can be a bit of a shock to the system, to say the least, especially for novice runners. Sometimes, when someone is stressed (mentally or physically), the body reacts to this by feeling sick, or even being sick.

If you do find yourself being sick during or after the race, make sure you keep yourself hydrated. Vomit still counts in the ‘what goes out, must go in’ rule when it comes to balancing fluid losses (such as vomit and sweat) with intake.

And, one of the biggest reasons people fall sick during and after marathon is dehydration - especially when running in hot weather.

Don’t forget, it’s not just water lost in sweat and vomit, but essential nutrients electrolytes too. Replace these with drinks containing glucose - some post-race oral rehydration salts wouldn’t go amiss either!"



 Did you know that one of the biggest reasons people fall sick after running a marathon is dehydration?!  


7. Urinating 

Talking of drinking more fluids... You gotta go when you gotta go (even if there are no portaloos about). Slightly more serious, is the fact that you can pee blood…

What the doctor says

"One of the organs that we doctors are most concerned about in marathon-runners is the kidneys. The kidneys don’t like marathons: a recent study found evidence of acute kidney injury in 80% of marathon runners!

A reminder of their function: the kidneys are responsible for filtering the blood, removing waste products and excess water by means of urine production.

If you notice blood in your urine, this could indicate damage to the kidneys. If this occurs while training, see your GP as soon as possible and put training on hold in the meantime (until your kidney function has been properly assessed). Similarly, if you notice blood in your urine during a race, don’t ignore it until the end – seek medical attention immediately. Although acute kidney injury is often fully reversible, there’s a chance it could lead to long-term complications."


8. Tummy troubles 

In the world of running, this is termed “runner's trots” and it happens to the best of us (remember Paula Radcliffe’s moment in 2005?).

What the doctor says

"Although the cause ‘runner's trots’ isn’t clear, some put it down to the ‘jostling’ of the bowels with the motion of running, while other theories include lack of blood perfusion to the gut.

A bout of diarrhoea before a big event is also not unusual, as again it’s part of our body’s natural stress response.

Some people, however, are predisposed to bouts of loose bowels, such as those with conditions like irritable bowel syndrome (IBS).

The most important tip for managing this, again, is to stay hydrated (you should be getting the gist of this, by now!). Make sure to replace lost fluids and electrolytes by means of oral rehydration solutions, to prevent dehydration."


(9.) Periods 

This is an interesting one. It is by no means gross having a period (quite the opposite, it is completely natural – mother nature’s little monthly gift). However, it may feel uncomfortably or ‘gross’ for the runner. But, we’d like to bring your attention to two notable females (running almost 20 years apart). Firstly, German long distance runner Uta Pippig, who won – we repeat, won – the 1996 Boston Marathon, after starting her period and experiencing bleeding throughout the race. Secondly, Kiran Ghandi, who ‘free bled’ while running the 2015 London Marathon, “to break the taboo around periods” and highlight the fact that many people around the world don’t have access to sanitary products. These women are overcoming boundaries, championing female rights and kick-starting an important conversation about menstruation!

What the doctor says

"If you’re a woman who has regular periods, chances are you’ve been running while on your period before. Although portaloos are not the ideal location to be ‘dealing with’ an unexpected situation, sadly you don’t have much choice during a marathon. If marathon-day falls around your time of the month, make sure to keep sanitary products handy.

If you often suffer from menstrual cramps, then perhaps carry an ibuprofen or two in your pocket, just in case! That said, exercise is good in alleviating cramps, and don’t over-do your use of ibuprofen, as this type of anti-inflammatory medication is excreted by the kidneys, which as we’ve mentioned are already overworked while running marathons!

One important consideration, though, is not to forget if you’re using tampons, that the 8-hour rule still applies. Don’t get caught up in the day’s exciting events and forget to change it within this safe window, as keeping tampons in-situ longer than puts you at risk of developing potentially life-threatening toxic shock syndrome (TSS)."


*While these eight things can and do happen to runners, it doesn’t necessarily mean that they will happen to you. There are also plenty of tips and tricks out there, to help you deal with any situation that might arise while you are taking on your 26.2 miles. And, if you’re worried about anything at all, our GPs are here for you! Simply find your nearest LDC doctors surgery (with nine convenient central London clinics we shouldn't be too far away when you need to find a GP) and book a consultation, in which you'll be able to discuss any issues privately and confidentially. As always, if you need a private GP London Doctors Clinic is here for you.