What happens to my body when I run a marathon

I've run two marathons so far and here is a summary of my experiences wrapped into the findings of 8 Things that happen to your body when you run a marathon, the physiology of Marathon running and ten unexpected truths about running a marathon. All in all running a marathon is a bit like getting pregnant. If you know about all the possible consequences, you would never do it unless you are insane. It involves pain, months of preparation and when you are finished you feel exhausted and happy.

Your body will go through hours of training

A marathon training schedule is demanding with 5 - 7 runs a week adding up to 100 - 250km of running a month. This process increases gradually over a time from 6 - 9 months and is depending on your starting level and goal time. Be prepared to say no to social arrangements and adopting your body to new workloads over time. This is the doom and gloom of marathon training.

For my first marathon i trained 6 months and finished it in 3:58. I solely concentrated on running and kept my schedule for a great result.

I prepared a year for my second marathon and it was a fail finishing it in 4:06. My major mistakes were not getting my long runs done and thinking I could supplement miles run through weight training, which was quite stupid in retrospective.

Your body will change its shape

On average marathoners lose 2- 5 kilograms and 2 centimeters in height during a marathon run. Your calves will get more muscly and your waistline will shrink. Depending from where you start you will lose or gain weight during training.

If you start underweight and very skinny most likely you will develop more muscle in places you did not have muscle before. As muscle is denser than fat tissue and more tissue is heavier than no tissue you will most likely gain weight.

If you start slightly or extremely overweight the cardiovascular training will help you to shed off some of these unwanted pounds.

Personally I lost 15kg in 2013 preparing for my first marathon and gained 8kg in 2014 in preparation for my second as I started a powerlifting routine.

You might lose some body parts

Marathon runners report frequently that they lose toenails or get the sniffles during a run (in which you also lose microscopic body parts). There is also an account of a 22 year old who got gangrene and his leg had to be amputated.

In my marathon journey i never had problems with toenails falling off or amputated legs (which is a serious thing i do not want to belittle). I also can not say that I had a runny nose on marathon day itself in both cases, but definetly during my long runs in practice.

You will have a breakdown

Somewhere in the training or during the marathon itself you will get some form of breakdown. Be it the famous wall or getting fed up with the regime. It will happen and has happened to every runner i know.

I did not run both of my marathons through as I had serious pain after km 23 - 24 in both instances and had to mix walling and running. This was mainly due to me being overambitious, over pacing and not putting enough mileage in during preparation.

You might drop dead

Legend has that the first marathoner to ever complete the distance running, the Greek Pheidippides, dropped dead on arrival. This holds true through the ages as there are reportedly deaths at marathons on a regular basis. Here are some numbers on how likely it is that you die on the circuit.

Between 1976 and 1994 the Marine Corps marathons had 215.413 entrants. 4 of them died which translates to a mortality rate of 0.002%.

In a later study in 2015 this number improved to one death in 220.000 finishers or a mortality rate of 0.0005%.

Statistically this is not a high risk. Compared to mortality rates during child birth it is roughly 130 times more likely to die during childbirth based on numbers from 2010 and 44 times more likely to die in a car crash. Yes on a site note childbirth is more dangerous than a car crash based on these statistics.

If we stick with sports it is roughly 5 times less likely to die (which is way more likely than i thought) in a football game. Still if you want to stay alive, keep away from sports which involve sticks as lacrosse and hockey are roughly in the same ball park as marathon running. Your pick.

Apart from all the statistics I took part in a half marathon and a marathon in Ireland in 2013. In each of those one man died. Noone got hurt in 2014.

Before you freak out, usually it seems to be that the ones who died did one of two things

Not train enough for the time they wanted to run
Not consult their doctor often enough to diagnose some kind of heart or cardiovascular condition

But enough of dying for now.

You will lose fluids

The average runners sweat out during a marathon is 1.2 liters an hour. In addition it is recommended to replenish this, so you will drink somewhere between 200ml to 1 liter an hour during the marathon and that water also has to go somewhere.

Out of my own experience i can tell you will have to make a bathroom stop and I do not recommend to wear very airtight clothes. If you do the sweat will evaporate and leave the salt that is within the sweat as stains in your full body suite. Been there, done that, not recommended.

You will adapt and grow

I personally would not miss the experience of running a marathon. The dedication, the people, the awarding feeling when you finish the line all make it worthwhile. As with pregnancies, love, a great job or your children, where there is greatness, there is struggle.