Maximising your running potential through gut health

Our resident health expert, Dr Juliet McGrattan, gives us the lowdown on how running can affect your gut health...

You learn a lot about yourself when you’re a runner. You tune into your body, what it needs and how far you can push it. When you’re asking new demands of it, it can quickly let you know if it doesn’t approve. This is particularly true when it comes to the gut. Stomach and bowel issues are really common in runners. A study looking at 145 runners over 30 days found they experienced at least one gastrointestinal (GI) symptom on around 81 per cent of runs and moderate to severe symptoms on around 18 per cent of runs.

Developing your running goes hand in hand with figuring out what to eat and how to fuel your exercise but our understanding of the gut has deepened over recent years. The gut is very much more than a muscular tube transporting food through your body. It’s now understood to play a role in multiple body systems. It’s packed with receptors that communicate with the rest of your body via nerves and chemical messengers. From your immune system to your mood, from your metabolism to your heart health, your gut is now known to be involved. To be a healthy runner you need a healthy gut.

Let’s explore why some runners struggle with their bowels, what can help and steps we can all take to have a healthier GI system.

The Runner’s Trots

The runner’s trots are something all runners dread. The sudden and overwhelming urge to open your bowels when you’re running, often accompanied by bloating, wind and cramps, is not pleasant or easy to deal with. For some it’s a one off but for others it’s a recurrent problem that hugely interferes with their ability and confidence to run. Long distance and public events, particularly urban ones where there’s no hedges to nip behind, can feel impossible. Stools are usually loose, sometimes explosive and just have to be evacuated with urgency; there’s no ‘holding on’ until the end of the run!

What causes the runner’s trots?
There are lots of theories and reasons as to why the runner’s trots might happen and in reality, it’s probably a mix of factors.

Here are three common theories:
  1. A lack of blood flow to the gut. When you’re running, your skeletal muscles are working hard. To give them adequate oxygen, blood flow to muscles is prioritised over the gut. The gut isn’t impressed with the reduced blood flow and reacts accordingly.
  2. A surge of adrenalin. The adrenalin released during running speeds up the time food takes to go through your digestive tract. This is an extension of the fight or flight response, where fear can cause diarrhoea.
  3. Gut irritation. The up and down movement of running causes the gut to jiggle around. This irritation leads to bowel emptying.

Who gets the runner’s trots?
Surveys show over one third of runners can be affected by the runner’s trots but some people seem to struggle with this more than others.

Any of the following factors can increase your risk of the runner’s trots:

  • Pre-existing bowel conditions such as Irritable Bowel Syndrome
  • Eating too close to running so there’s not enough time for food to be properly digested.
  • Eating the wrong foods before running (what is ‘wrong’ varies from person to person).
  • Intolerance of running fuels
  • Inadequate hydration
  • Being a new runner – it can take time to train your gut.

It’s not just about the bowels
When we think about gut health and running we tend to focus on the bowel but let’s not forget what’s happening higher up. The stomach can cause problems too with nausea, indigestion and acid reflux being common complaints from runners. The factors above and solutions below apply just as much to stomach health as they do to the health of your bowel.

Tips for good gut health as a runner
What can you do if you don’t have a cast iron gut like your running buddy? How can you minimise the risks of needing a toilet mid run? And what steps can you take to improve your gut health generally?

Here are 10 simple tips for good gut health as a runner:

  1. Allow enough time between eating and running - this may be as much as three hours for some runners
  2. Choose easily digestible food before you run - avoid anything too fibrous or fatty as these foods are slower to empty from the stomach. Keep a food diary to see if certain foods upset your gut. What you drink can affect you too – caffeine, alcohol and fruit juices are common culprits
  3. Hydrate properly before and during running. Dehydration increases the risk of GI problems during exercise
  4. Train your gut – gradually increasing your distance and intensity will allow your gut to adapt
  5. Practice your fuelling – your body has energy stores for around 90 to 120 minutes of running, beyond that you need to take on easily available energy from foods, drinks or gels. Find what works for you and practice so you feel confident that you can stomach what you plan to use
  6. Stick to natural foods and products where possible. Additives such as sweeteners and preservatives can upset sensitive guts
  7. Calm race day nerves with relaxation and distraction techniques. Feeling anxious or tense will increase your risk of gut issues
  8. Eat a very varied diet day to day – variety is key for gut health and will help to keep your gut microbiome (the hundred trillion micro-organisms that live in your gut) diverse and healthy. How healthy your gut microbiome is can influence your wider health. A good tip is to eat as many different coloured fruit and vegetables as you can over the week
  9. Build routines, plan and prep. Being organised, knowing what you’re eating when and having the right foods and fuel in the cupboard prevents you grabbing something quickly and hoping for the best
  10. Remember things change. What suits you and works for you might alter over time. For example, the changing hormones of women in midlife can affect the fuels that suit them and following a viral bowel infection you can develop temporary food sensitivities.

It’s easy to be frustrated by your gut if it’s interfering with your running but patience, trial and error and training will resolve most issues. Remember, if you have a change in your bowel habit that’s not normal for you or you see blood in your stool, make an appointment with your GP.