That horrible feeling as you’re running. Cramping, bloating, and an undeniable urgency to find a bathroom. Also known as runners gut. Runners are twice as likely as other athletes to experience gastrointestinal discomfort, with some studies indicating that 25-50% of elite athletes experience gastrointestinal symptoms during training or an event, and can ruin what was otherwise an enjoyable run.
What are the symptoms?
Diarrhoea, urgency to defecate, bloating, cramping, gastrointestinal pain, reflux, nausea and vomiting are all common symptoms of runners gut. The final three symptoms mentioned here are more likely to occur in triathletes or cyclists as well, due to pressure on the abdominal area.
What are the risk factors?
Age, Gender, Level
Younger athletes are more likely to suffer from runners gut than older athletes. Interestingly, elite athletes are more likely to suffer these problems as well. It is thought that younger athletes are less likely to have a highly conditioned gut, are more likely to become dehydrated due to lack of experience. Females and those prone to anxiety are also more likely to suffer from symptoms.
High intensity Exercise
High intensity exercise can result in gut ischaemia, which is where blood flow is diverted away from the gut. Research shows that training at 70% of VO2max can reduce this by 80%. This itself can cause symptoms of runners gut, as well as reducing the body’s ability to digest any consumed food or fluid.
Dehydration of more than 2% can result in stomach issues. When running, blood is diverted away from the gastrointestinal tract so it can be used by the harder working muscles. This can result in damage to the intestines, along with difficulty actually consuming the necessary fluids. When blood is diverted away from the stomach, digestion slows, however if there isn’t enough blood flow, the stomach then rejects any food or fluid that it is provided with, as blood flow is required for this to occur.
People with irritable bowel syndrome are more likely to develop symptoms of runners gut. Due to the nature of their condition; these people are more likely to get runners gut type symptoms anyway, thus it makes sense that running would exacerbate this.
The role of food
Type and timing of last meal before exercise can be associated with runners gut. Some report increased likelihood of runners gut if they have recently consumed alcohol, whilst high fat, fibre and protein meals prior to exercise are more likely to cause symptoms, as they are digested more slowly, thus need more time to be removed. Further to this, some people do not tolerate gels, sports drinks and chews well, thus it is important to ‘practice’ with these products. Your gut can be trained to tolerate higher volumes of carbohydrate, and to tolerate gels, but this takes time and practice.
How to handle it?
Ensure that you are well hydrated leading into your training sessions and events, if doing a longer session, take water/electrolyte drink with you, or at least plan a route that includes lots of water fountains. Choose something low in fibre, fat and protein, with an adequate serve of carbohydrate as your preworkout meal, and ensure you have practiced using what you want to use race day, both during and before hand before. For more information about the importance of experimenting with your food, see my post ‘Play the way you train’. If you have irritable bowel syndrome, avoid eating possible triggers in the lead up to training or an event, to minimize the risk of symptoms.
Have you ever had runners gut? What do you do to stop it happening?
Chloe McLeod is a dietitian at BJC Health.
This blog focuses on diet & nutrition generally and diet & nutrition in relation to the treatment of arthritis and arthritis-related diseases. Contact us if you'd like our help in managing diet-related health issues.