Whether you’ve been clocking up 5Ks or have been on that half marathon training plan hype, then you’ll likely be au fait with the gut issues that long pavement pounds can cause.
From feeling sick after a long run to nasty tummy gripes, runner’s stomach is most definitely a thing.
‘I get asked about feeling sick after long runs all the time,’ says sports nutritionist and author of The Runner’s Cookbook Anita Bean. ‘It’s estimated that between 30 to 50% of endurance runners will experience some kind of gut problem, whether that’s feeling sick and general discomfort, flatulence, the so-called ‘runner’s trots’ or even vomiting.’
So, Why does this happen? There’s a few reasons. Let’s break it down.
Runner’s stomach: why you feel sick after a long run
‘The most common explanation for runner’s stomach is to do with the physical jostling of the intestines,’ says Bean. ‘Running is high impact. Generally, people are okay for an hour or so, but between 60 and 90 minutes, all of that shaking of the intestinal tract can make you feel nauseous.’
YOUR BLOOD FLOW ISN’T GETTING WHERE IT NEEDS TO BE
‘When you run, blood that would normally go to your gut is diverted to your active muscles. This means that you experience a temporary starvation of oxygen to the digestive organs, which can affect your gut motility,’ explains Bean. Basically, the typical movement, or rhythm of your gut becomes sporadic, which can cause pain, discomfort and nausea.
YOU’RE FEELING ANXIOUS
‘If you’re running as part of a race, or something you’ve trained for, you might be feeling anxious; your adrenalin levels might be high,’ says Bean. As we know, your gut and your brain are very much connected, and so feeling a bit jumpy can make you feel queasy.
YOU’VE EATEN FOODS THAT ARE IRRITATING YOUR GUT
‘Certain foods are irritating for your gut,’ says Bean. ‘Of course, this varies from person to person, but it could be high fibre foods like whole grains, beans and lentils, or brassica vegetables like cauliflower and broccoli.’ Because these can cause extra gas production in the gut, you can end up with stomach discomfort.
‘Energy gels, where you’ve got a high concentration of sugars like glucose or fructose, can also cause the gut to spasm or product excess gas – which can result in pain,’ says Bean.
‘A lot of runners leave it too late into their run to have a drink,’ says Bean. ‘Until an hour has passed, or so. By that point, you’re already dehydrated, your gut hasn’t had anything in it for an hour and then you drink, which can set off spasms.’
YOU JUST HAVE A SENSITIVE GUT
Some of us are just more prone to stomach issues than others. ‘There’s going to be variability between us,’ says Bean. Some people are more able than others to handle hours of their intestines being jostled – and some of us aren’t. Sad, but true.
So, how can you try and mitigate the whole runner’s stomach thing? No one solution is bulletproof, but, if you are prone to sickness during or after a long session, try these tips.
How to try and prevent your runner’s stomach from getting too nasty
EAT THE RIGHT BREAKFAST
‘Before a big run, you want to eat something that’s easy to digest, high in carbs and low in fat,’ says Bean. Why? ‘Because high fat foods take longer to digest, they can lead to discomfort when you’re moving.’
In terms of food recommendations, Bean says that something like porridge with banana, toast with eggs and a little bit of avocado or Greek yogurt with granola could work – but you need to do a bit of trial and error and see what works for you.
TRAIN YOUR GUT
‘In the same way as you train your muscles, you need to train your gut,’ says Bean. ‘Train,’ refers to adjusting your gut so that it’s happy to have food and drink while you’re on the move, so that you can stay hydrated and energised without feeling sick.
‘As part of your training plan for a long run or a big race, gradually introduce food and fluids,’ says Bean. ‘So, you might start by having a bite of a banana and a few sips of water before you set off, then another bite and a few sips after 30 minutes, and then the next 30 minutes and so on.’
Doing this allows your body to dial up towards being able to handle having stuff put in it while you’re running – without upsetting your stomach. ‘Ultimately, you want 10 to 15 grams of carbs every half an hour,’ says Bean. ‘Something like a medjool date or half an energy bar.’
She says that it’s important to figure out your fuelling plan way in advance of a big race, so that you know what you can get comfortable with.
Dosed up on the knowledge? Then go forth and hit that long run hard.