-- Marathon Running Information, Coaching and Advice from Coach Joe English

Training: why do I get side-aches when I run?

Coach Joe English

Coach Joe English

Boy we get this question a lot: why do I get a side-ache or pain in the right side of the abdomen when running?

I’ll start by noting that this is a very common issue and it can be a real downer. Side aches almost always occur on the right side, just below the point where your rib-cage meets the side of your body, but they can in fact happen on the left side at times as well.

There’s a lot of debate over the cause of side-aches, but the best guess is that the ache comes from the up and down motion of running putting stress on the diaphragm. What we see with runners is that there may be some combination of things that makes side-aches worse for them as individuals, such as eating or drinking before running – or not eating or drinking before running. The problem can be highly dependent on the person.

Side-aches are caused by the up and down motion of running putting stress on your internal organs, most especially when you’re breathing out. When breathing out, there is an increase in the tension on the ligaments holding your organs in place, in particular the liver (which is a big and heavy organ), as the diaphragm comes upward. If you also happen to be hitting the ground with your foot at the same time, this banging can cause your side to ache.

Here are a couple of things that you can do to help:
First, become a belly breather – concentrate on taking deep breaths and expanding your belly when you breathe. You can practice this by laying on the couch with a book or magazine on your stomach and lifting it up and down as you breathe. If you breathe shallowly with just your lungs, you won’t see your belly moving in and out as much. Belly breathing not only helps with side-aches, but also puts more air in your lungs, giving you more oxygen with each breath.

Second, change your breathing ratio – Your breathing ratio is the ration of breaths you take in to the number that you breathe out. Since it takes longer to pull air into your lungs than to expel it, you’ll notice that you have a ratio of a certain number of steps breathing in to a certain number of steps going out. Usually this will look something like 2:1 (two steps while breathing in to 1 step while breathing out). If the pattern always results in you breathing with the same foot hitting the ground, this can cause side-aches. You can read a great article on side-aches with an explanation of this by clicking here. Try to change the pattern so that the other foot hits the ground.

Third, try slowing down – if you slow down your pace, and breathe from your belly, you should be able to increase your breathing/step ratio to 3:2 (three steps in to 2 steps out). This more relaxed breathing ratio my alleviate the side-aches.

Fourth, experiment with what you eat and drink and when – try eating or drinking something before running – or change up the types of food (for example from solids to liquids) before your run. Sometimes a combination of different weights of foods or liquids in the stomach can contribute to your side-aches.

Finally, know that as you become a stronger runner, side-aches tend to be less of a problem. This is most likely due to increased strength in your core muscles. This tends to lessen the incidence of side-aches as well.

So, give a try to two things: breathing from the belly and changing up your stride pattern. These may help cut down on the side-aches. That’s probably a better solution than my high school track coach told me: “just run through it.”

Coach Joe English, Portland Oregon, USA
Running Advice and News


18 responses so far, want to say something?

  1. 1. Brenda Polster January 29th, 2008 at 3:17 pm

    Thanks Coach Joe
    I thought I’d throw in my own experience with food contribution to side aches. I’ve found that having dairy the morning of or even evening before my long runs correlated with getting side aches. No milk, no ache. I’m not lactose intolerant, but found that it does affect my running.

  2. 2. coachjoeenglish January 30th, 2008 at 10:30 am

    Ah milk rears its face once again.

    It’s interesting to hear you say that milk may give you side-aches. Milk gets blamed for all kinds of ailments and I’m not sure which are real and which coincidental.

    Some people do suggest cutting out dairy before running, but I’ve eaten dairy products for years and have never had trouble. I think this is truly an individual issue based on your diet and tolerance for milk products.

    Coach Joe

  3. 3. jim January 31st, 2008 at 8:27 am


    Interesting note..I went to the Reebok Indoor games this past weekend and witnessed a world class athlete having side stitch pains. Read the recap below. apparently she has had this problem for awhile and cant solve it. We watched her hold her side for 2 laps ( at a very fast pace) and still win.
    Im sure she has some of the best trainers and doctors trying to solve her problem..with no answers yet

    Women’s 3000m: Tirunesh Dibaba Wins but Is Upset Afterwards
    It was disappointing to see Tirunesh Dibaba basically race the same race as Meseret Defar (Dibaba the 3000m, Defar the 2 mile) and not have them in the same race, but there is no way these two will race each other without a lot of money or prestige on the line. The best solution would have been for one of them to run either the 1500 or the 5k.

    Nonetheless, Dibaba opted for the 3000m and ran before Defar. The women’s 3000m was the Dibaba show as Tirunesh and her sister, Ejegayehu, dominated from gun to finish. As would be expected Tirunesh got the win (she overshadows her sister so much we think most people don’t realize how good Ejegayehu is. Ejegayehu ran 30:24 for silver at the 2004 Olympics in the 10k and has 2 World Championship track medals as well)

    The 1600 was reached in 4:36.1 and Tirunesh would actually pick things up the 2nd half to finish in 8:33.37. Nonetheless, her expectations are high and after having set 2 world records at this meet (in the 5k in 2005 and 2007) she was disappointed afterwards. She had a sullen look on her face as she addressed the press afterwards through her translator. She said she was inflicted by the same stomach pains that hampered her run at the World Championships last year (she still won the gold). “It’s a very serious problem, and I think it’s getting worse. We have seen so many doctors and they told me I have nothing,” her translator told the press as quoted by David Monti (the translator was very hard to hear).

    A rare site was what was going on in the back of the women’s 3000m. Sally Kipyego the NCAA star who just dominates the NCAA ranks was almost lapped and finished in last place in 9:05.45. It just shows you how great the top pros are as Kipyego’s time was still a collegiate leader.

    Event 13 Women 3000 Meter Run
    Name Year Team Finals
    1 Tirunesh Dibaba ETH 8:33.37
    2 Ejegayehu Dibaba ETH 8:36.59
    3 Megan Metcalfe CAN 8:52.85
    4 Christin Wurth-Thomas USA 8:54.97
    5 Sally Kipyego KEN 9:05.45
    — Miesha Marzell USADNF

  4. 4. coachjoeenglish January 31st, 2008 at 10:07 am

    Fascinating stuff Jim!!!

  5. 5. Rebecca Kimball April 13th, 2008 at 10:48 pm

    As far a side aches go the only times I get them is when I am running on a decline, usually a steep one. I’ve noticed that it wont subside until I hit an incline. It’s very frustrating, especially when your running in a race.

  6. 6. bob October 1st, 2008 at 12:49 pm

    wow cool this is so cool is there a pose that u can run in to prevent side aches ?

  7. 7. Joe English October 1st, 2008 at 1:27 pm

    Bob — it isn’t generally the pose, but rather your breathing pattern that will make the most impact.

    Try paying attention to your breathing and make sure that you’re not inhaling or exhaling every time you step with the same foot. If you do, try changing your breathing pattern to see if you can be breathing as your foot-falls alternate sides. This may help with the side-aches.

    Good luck!


  8. 8. Nick October 30th, 2008 at 9:33 pm

    All I can say is eat about 8 ounces of roasted mutton exactly 45 minutes before your run/jog. It really gets rid of the side aches. Don’t eat anything else with it. Make sure to stretch before and after your run/jog.

  9. 9. paul February 19th, 2009 at 3:52 am


    Side pain when you run is mechanical because you don’t get it when you don’t run, eating certain foods before you run will not affect the pain and is most likely coincidental.
    Everyone is different and you each need to analyse the way you run and walk so you can combat the problem. I suggest creating a diary for the same route for a week or 2 that you train on, noting the point at which you achieved the side ache then start thinking about if it is a time problem, or road level issue or how your breathing changes at this point.

    I haven’t run in years due to vitamin d deficiency however if yuo have flat feet and poor core muscles you are more likely to get side ache. get some proper orthotic inserts and work on your abs and hip muscles and do breathing exercises.

    If anyone wants to discuss anything to do with running give me an email happy to help.



  10. 10. PHIL July 7th, 2009 at 2:50 am


  11. 11. coachjoeenglish July 10th, 2009 at 3:24 pm

    Phil — I think that the time off from running was likely coincidental to the side aches.

    As we say in the artcle, side aches are tyically caused by breating issues or weakness in the core muscles. It is possible that due to the time off, you've changed something in your running form, but three weeks is a short time to be off and have this result. If you were a new runner, I would suspect weakness in your core.

    Try taking deeper breaths when you run, inhaling deeply with your stomach muscles. This should help with the side aches and it will also give you more oxygen for your muscles to use.

    Good luck.

    Coach Joe

  12. 12. jason July 28th, 2009 at 3:05 am

    this is all helpful but i hav no idea about the breathing ratio.
    plz reply and tell me about the breating ratio

  13. 13. coachjoeenglish July 29th, 2009 at 5:55 pm


    Breathing ratios are the ratios (or rhythm) of your steps and breathing. If you take a deep breath in right now and then let it out, you'll notice that it takes longer to suck air in than it does to let it back out. When you run, as the effort level goes up, your body is going to need to pull more air into your lungs so you'll start breathing faster and faster as the intensity of your run goes up.

    The breathing ratio is then the number of steps taken while taking a breath in to the number taken to breaths out. Go out for an easy jog and you'll probably find that you are taking about 3 steps while taking a breath in and 2 steps while you let the breath out. As you speed up, you will need to quicken this ratio to about 2 steps while breathing in and then 1 steps while breathing out. If you're really pushing hard, the ratio will go down further to about 1 breath in to each step and 1 breath out to each step. This is breathing very heavily.

    Why does this matter at all? Two reasons, for one thing, taking much deeper breaths often helps clear up side-aches. In order to take deeper breaths, you will have to slow down your breathing (taking longer breaths in) which will increase the breathing ratio. So perhaps if you are taking lots of short, quick breaths you may be breathing something like 2:1 and taking deeper breaths will get you to 3:2 or 4:2. The second reason is that some people theorize that if you step on the same side every time you exhale you, this can also cause side-aches. This would mean that you were breathing on some even ratio like 1:1 or 2:2. Again, getting yourself to something like 3:2 will change this rhythm and might help clear up the side-aches.

    Keep in mind that these are hard things to change. Our breathing rhythm gets quite entrenched. The big thing may be to slow down and take deeper breaths and this should help with the side-aches.

    Coach Joe

  14. 14. 3 Mile Runs (5 km Run) | Justin Horning's Blog February 9th, 2011 at 12:36 am

    […] in @ 7mph for a 29 minute time. Bummer. I found out why side-aches hit the right side when I run here. It’s interesting to think of the timing of your strides and breath rhythm. My intuition […]

  15. 15. 3 Mile Runs (5 km Run) | jlhorning's Blog February 24th, 2011 at 1:28 am

    […] in @ 7mph for a 29 minute time. Bummer. I found out why side-aches hit the right side when I run here. It’s interesting to think of the timing of your strides and breath rhythm. My intuition […]

  16. 16. Jeff August 4th, 2011 at 10:14 pm

    I’ve battled side aches for years, but not every time I run. As a novice runner, I used to think that poor diet, and being generally out-of-shaped caused it. But after years of running, I definitely have noticed that it is simply more a matter of body stress, though I do feel like having food or water in your stomach just further adds to the the body stress. Also, if you are carrying a lot of water weight in your body, that also adds to the stress. The harder I run, and the more the terrain varies in elevation, the more likely I am develop a side ache. Belly breathing is the single most effective thing I’ve learned to do to help to remedy most side ache pain. However, sometimes the side ache pain can become so great that your only choice is to slow down and deeply belly breath. In this case, I’ve found that if you slow down for a quarter to a half a mile, and then breath deeply using you diaphragm the whole time…the side ache will go away ( and you shouldn’t have to slow down to a walk to do it either ). I think I’m going to try watching my breathing to step ratio as suggested in this article. That is one thing I haven’t tried. Maybe that will prevent me from having to ever slow down.

  17. 17. Traumanurse April 14th, 2012 at 11:27 pm

    My 10 year old started training for a 5k with me and always gets a sideache, I was getting a bit upset thinking it was “just an excuse” to stop running even though I used to get them and was able to make them go away by changing my breathing. I am going to get him to try the “belly breathing” hope it works I really enjoy running with him but hate to have to stop usually at the 1.5 mile mark, I have even started running twice a day once by myself so can get my miles in and then later with him. Hope this works! Thanks for all the info

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