Last Updated: February 20th, 2022

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half marathon side effects

Planning your first half-marathon?


As with any good things in life, it also has some side effects.

Don’t think that I’m discouraging you in any way. I want you to understand what to expect out of a half marathon so that you can prepare better.

Here are 7 gross side-effects of half marathon that no one talks about.


Well, if you discuss the negative side of something, it takes away the golden aura around it.

The same goes for running a half-marathon or a full marathon.

Needless to say, these things need to be discussed and you need to be prepared to deal with them.

Don’t worry…these side effects are not life-threatening, but nonetheless they are annoying.

As per my experience, these are the most common side effects of running long-distances.

Also, I’ve found that if you equip yourself a little ahead of time, you will be able to deal with them better.

Here is a half-marathon checklist that will help you to deal with the below problems and also will equip you with the right set of gears to keep the problems at a minimal.So, let’s jump right ahead into it and find out how we can deal with these side effects of running a half-marathon…

7 Gross Side-Effects of Half Marathon That No One Talks About

half marathon harmful effects

1. Muscle Inflammation

You have run a half-marathon. YAY!

You hate yourself even more for doing this to yourself… More YAY?

Not in the mood for my pathetic jokes?

Let’s skip them anyway… :p

Now that you have already run a half marathon, your body must be paining like hell.

There are soreness and stiffness everywhere and at times you feel like crying from pain.


So what can you do now?

Some of the answers lie in the training.

If you increase the mileage gradually during the training, you will minimize the chances of inflammation afterward.

But that is for next time…

What can you do now?

Take refuge in your compression gear – yes I mean it.

They put a little bit of pressure on your muscles and improves blood circulation.

In turn this ensures effective removal of lactic acid from your blood which is the primary reason for your soreness.

This will literally help you to recover faster from this continuous pain and suffering.

(In fact, I cannot live without these compression tights of mine. They are a bit tighter than my regular running tights. But I feel a lot less pain after wearing them for a day. Once, I experimented not wearing them after my long run. I swear by God, I will not repeat the experiment again.)

2. Chafeing

This is another thing that will make sure you know that you have run a half-marathon and that too at every step throughout the day.

Now, what is chaffing?

This explanation is for the newbies…

Veterans! please bear with me…

When your clothes rub against your skin continuously, it gets painfully sore.

You can see the redness and if it is too much the skin may rub off exposing the tissue beneath it.

It is extremely sensitive to touch and you will feel extreme discomfort every time you step into the shower or move around.


Any of these anti-chafe balms. Use it liberally on your body. I’m especially careful where the cloth joints will touch my skin, like under the breast, thigh joints, etc. These anti-chafe balms are water-resistant and will stay on until you are done with the race. This will minimize your chances of chaffing.

But what if you are already chaffed?

I’ve found that any ointment for cuts and bruises are effective on these as well. Try it…You should get a lot of relief by the next day.

Also, wear loose clothes so that it doesn’t touch the chafed area so that your skin may breathe.

3. Injuries

Running is a very intensive sport and it puts your body through a lot of stress.

And you are running 13.1 miles…Oh!

You are bound to pick up a shin splint here, plantar fasciitis there…

With some stretching and proper rest, you will be able to get rid of most of your aches and pains.

For the other injuries, it’s best to visit a physio or a doctor after a couple of days.

This will help you to recover faster and you will be able to return to tracks faster.

But whatever you do, you should not self-medicate…it may delay your overall recovery…

Related: How to avoid running overuse injuries?

4. Black Toe-nails

Do I hear an eww…

Black toenails are hardly something that any runner discusses.

It gets lost in the glory of running a half marathon.

But, then again it is there rearing its ugly head and giving you that uncomfortable feeling.

Why it occurs?

Mainly because of your running shoe.

When you run, your toes get repeatedly pressured by the upper, side or front of your running shoes.

This pressure can cause the underlying blood vessels of your toenails to rupture and bleed.

This gives that black color to your toenail.

What can you do?

Visit your doctor and drain it out if it is bothering you too much.

Otherwise, leave it as it is. It will not cause you any harm.

But mostly, your toe-nail will fall off.

Whatever, you do, don’t try to drain it yourself. You may cause more damage to your toe.

Also, next time try wearing running shoes that have a deeper toe-box as black toe-nails have a tendency to reoccur.

5. Blisters

Blisters are very common among runners especially long-distance ones.

Blisters are caused by the rubbing of your running shoes during the run.

Fluid accumulates under that area to protect the underlying tissue.

If you are dealing with blisters, then the best thing you can do is to leave them in the open and dry.

Do not wear shoes that touch your blisters.

This will increase the level of injury and you may end up with a deep scar.

If you keep it undisturbed, it will heal in a couple of days.

If however, you blister has popped, then clean it up with some antiseptic lotion and put some medicine on it.

6. Cough and cold

Running long distances like a half-marathon not only puts your body through a lot of stress but also, it can take a toll on your immune system.

Many runners have reported that they come down with cough and cold after a half marathon or a marathon.


Their immune system has gone for a toss.

If you observe the same thing in yourself, then the best is to take a lot of rest.

Sleep can be your best healer.

Also, focus on your nutrition and water intake.

These things can help your immune system to rebuild itself and you will be fine in some time.

Also taking some Vitamin C supplements may also help you to recover faster.

7. Stomach upset

This is a classic and many runners suffer from it.


Most of the time – consuming too much of running gels.

It is more common among marathon runners, however, half-marathoners may also suffer from it.


Running needs a lot of calories.

However, you should have only the quantity you are supposed to.

Mostly, we screw that up…and consume a lot more than we are supposed to.

Also, sometimes we chug down running gels with sports drinks – in other words, too much of sugary stuff down through your throat.

What happens then?

Your body cannot handle and digest that…


When you run… the blood from your stomach gets redirected to more active parts of your body.

So, your stomach gets less efficient with digesting.

Now you are overloading it with too much sugar…


A loud revolt and your frequent trips to the toilet in the following days of the half-marathon…

Instead, consume gels within reason and you will be just fine.

Also, make sure to include those gels during your training…don’t experiment with it on the race day.

Related: Are Running Gels Bad For You? Things you need to know


Running a half marathon may be one of the best decisions for your fitness level.

However, as with anything good, there are some nasty side effects as well.

With a little bit of care and caution, you can effectively deal with them.

So, go ahead and enjoy your awesome runs.

Madhusree Basu

Madhusree Basu

Author, Admin

Blogger and a fitness enthusiast. She loves running and Yoga and everything in between. She started running to manage her weight and to eat to her heart’s content. A true foodie at heart she shares whatever knowledge she has gained throughout the years about weight management and fitness.