Running Trots – What is it and what can I do to prevent it?

Running Trots – What is it and what can I do to prevent it?

Have you ever been running and suddenly had an urgency to use the bathroom? I hope you got there! As many runners have experienced, it is not as simple as just ‘holding on’. The cramps, bloating, gas and associated weakness that arises can totally ignore your dignity.
While so common, it is something not spoken about! I get it, it is disgusting and embarrassing! Further to the annoyance, your Garmin, Training Peaks or Starva data is also affected! How do you explain that one?
The good news is, it is something that can likely be prevented!

Trots, Stools, Faeces, Poo

First, what goes in must come out. And although many of the nutrients and energy contained in food is used by the body, there is also much waste.
What is it made of?
Poo, or otherwise known as faeces or a stool, if we would like a more polite or medical term, is composed of water (why constipation is often resulted from dehydration) and solid matter consisting of dead bacteria, indigestible food matter (indigestible fibre), cholesterol and fats, protein and inorganic substances like iron phosphate. These elements are all collected along the digestive tract from your mouth to your bottom.

Why the colour?

Without getting too far off topic, the colour can also provide a lot of valuable information about your health and digestion. The brown colour is attributed to by bile, a digestive fluid produced by the liver. It helps break down fats. When your food mixes with bile it turns from green to brown and it travels down the colon.
While black coloured poo can be caused by certain foods such as liquorice or blueberries, iron supplementations can also have this effect. It can also be a sign of blood further up your digestion tract and may require medical advice for further investigation, especially if you have been feeling ill, weak or lightheaded.
Red coloured poo, similarly can be attributed to by foods eaten such as beetroot, but it also a strong indicator you are bleeding from your digestive tract and seeking medical further investigation is recommended.

Transit time

Transit time, or the time a meal takes to appear in the toilet bowl from been eaten is usually between 12- 24 hours. In some instances, this is sped up, such as when you have diarrhoea. Diarrhoea will often have more of a green colour as it has had a faster transit time (less bile).
A faster transit time (less than 10 hours) means your food is passing through your digestive system too quickly. Chronic diarrhoea can result in less nutrient absorption from your food which can lead to nutrition deficiencies, electrolyte imbalances, cramping, anaemia and osteoporosis.
Anyone who suffers from chronic diarrhoea away from running is advised to be assessed for further investigations. Possible causes could be Inflammatory Bowel Disease, Ulcerative Colitis, Celiac Disease, Crohn’s, endocrine disorders and food allergies and sensitivities.
A transit time more than 2 days, is of concern as over time, it can increase the risk of bowel cancer, diverticulosis and candida (overgrowth of unfriendly bacteria), which weakens the immune system and increases one’s risk for all types of cancer.

How do I test transit time?

You can test your transit time by consuming something that is easy to identify in your ‘poo’ and then record the time it takes to appear out the other end. A cup of beets or corn work well! Your transit time is not fixed, it will change dependant on current health status, hydration and types of food eaten, especially fibre, as well as exercise.
Although it may not be the not the topic at the dinner table or a first date, regular checking of your bowel movements can be a valuable habit in monitoring your health and digestion.

Diarrhoea and Running

If you regularly have diarrhoea, even on the days you are not running, then running is likely only to exacerbate the root problem. Food intolerances (lactose intolerance and/or fructose malabsorption), irritable bowel syndrome, coeliac disease, a current viral or bacterial infection or current medication could be to blame, and medical advice is recommended.
Firstly, due to the biomechanical nature of running, you must acknowledge you have entered a sport that already has a higher risk. Another reason why we should talk more about it!

Here are reasons why:
– The vertical body position and impact of running (with organs jarring in the abdominal cavity)
– Altered gut motility from the redistribution of blood from the gastrointestinal tract to working muscles (gut ischemia)
– Altered neurological and hormonal functions of the body during exercise.
– Running is an energy demanding exercise and running at higher intensities often increases the impacts above.
– Those with higher levels of anxiety are also more likely to be affected. Especially for elite athletes, a sports psychologist is suggested to help with strategies to help manage.

Despite the fact we are at a higher risk, when health is in general all ‘well’, and pain, grumbling in the stomach, bloating and diarrhoea or the ‘urgency to defecate’ presents only when running, commonly there are multiple nutrition and behavioural related factors that can often be the main culprits. Having a greater understanding of these and making some simple adjustments may likely eradicate or significantly reduce the incidences! This is the good news!

The following factors are supported in research, found with my own experience and by consulting and coaching my athletes as a dietitian and run roach. Here are also some strategies to implement. Hopefully you can read over and identify which factor or factors are likely holding you back and you can make the changes needed!


The risk of nausea, vomiting, diarrhoea and other gastro-intestinal problems during exercise is significantly increased with dehydration of greater the 2% of total body weight. For a 60kg athlete this is 1.2kg or for an 80kg, 1.6g.
With many athletes failing to start their run well hydrated and then consume no or insufficient fluid during their run, especially if a long run, dehydration is a common culprit.
There is no one size fits all fluid recommendation for daily needs and racing. This is because many factors impact fluid losses including body size (surface area), intensity and duration, humidity and temperature. The clothing one wears, and the level of fitness also impacts sweat rate as some athletes with training become ‘more efficient’ at cooling themselves down (sweating).
Sweat rates can be tested in labs but can have limitations with accuracy when racing and training factors are changed. Taking your weight pre and post run, accounting for any taken on and lost (urine) is also a method to calculate sweat rate but proposes difficulties and potential errors. You would also need to take the weight naked to limit errors or sweat still held in your clothing.
I always recommend starting well hydrated. This means making sure in the 24 hours leading up to your run you are drinking enough fluid, regularly. If you run in the morning keep fluids up the day before and don’t leave the house without a tall glass or 2 (larger bodies will need more) of water and a trip to the bathroom. The colour of your urine is a good indicator of hydration status. No urine is a sure sign of dehydration as are bright yellow tones. A very pale-yellow colour is what you should aim for. Be cautious of any vitamin supplements you may be taking as they can cause urine decolourisation.
Like a car needs oil and petrol to go, so does your body! Water is the oil here but as oppose to oil in the car, we need to top this up more regularly. The aim for fluid during exercise is usually to prevent dehydration of greater than 2% rather than ‘over hydrating’. Having too much water also has it’s complications including the need to stop and pee! Athletes also like to avoid feeling ‘heavy’ or ‘full’. Fatal consequences also exist when excess water is taken in, which must be acknowledged but this is much less common.
A rate of 500ml per hour is an estimate I usually start with. Larger bodies, higher intensities, greater humidity and temperature may need more whereas smaller bodies, lower intensities and cooler temperatures will often result is lower sweat rates. Consider these factors and practice in your training!
Fluid absorption is also enhanced (less toilet stops) when combined with a sports drink containing carbohydrates and electrolytes. This is a superior option for runs greater than 60-90 minutes of duration where glycogen depletion (carbohydrate) is a limiting factor on performance. Carbohydrate is your bodies preferred “fuel” source and moderate to high intensity exercise. Consumption of easy to digest carbohydrates can allow you to work at higher intensities longer providing a greater quality training session and competitive advantage.
If you have long run scheduled, pack your gels and plan to run past a drink fountain or tap. If you want to have a sports drink plan to run loops past your house, car or a park where you can safely hide a drink bottle. You can also choose to carry fluid and nutrition with a fuel belt and flask or a camel back. This is advised for trail runners so that they are training more specific!

Too much carbs

There is a ‘sweet spot’ for optimal carbohydrate rate during exercise.
For events up to 2.5 hours of moderate to high intensity, continuous exercise, 30-60g per hour (with fluid) of easy to digest carbohydrate is recommended. For events greater then 2.5 hours in duration up to 90g per hour has shown to enhance performance when practiced in training.
Caution is needed here. Our body can only uptake approximately 60g of glucose per hour, so the remaining 30g needs to come from fructose, a type of carbohydrate and fuel source that utilises a different transporting system. Variability in absorption rates of both glucose and fructose will vary amongst individuals and training the gut is a strategy to increase absorption rates and limit any gastrointestinal issues. Many gels and sports drinks will contain a mix of these two sugars with a ratio of 2:1 which will often be labelled on packaging. Those with diagnosed fructose malabsorption should avoid fructose containing sports products.

Apart from carbohydrate feeding rate, too high of the ‘concentration’ of carbohydrate can also cause diarrhoea. Too high of concentration will draw extra water into the bowel to achieve a healthy osmotic gradient.
This is why sports drinks come with recipe instructions and gels are recommend are to be consumed in combination with fluid. Drinks during or before exercise of between 4- 8% carbohydrate concentration are ideal for rehydration and usually well tolerated. Drinks of greater than 10% such as caffeinated ‘energy’ drinks, fruit juices and highly concentrated cordial or sports drink are likely to cause gut issues in susceptible athletes.

Training the gut

Many are aware of the benefits of taking on nutrition during endurance events such as running but often leave it until race day to implement! They see everyone else do it, may be given some in their race pack and along with race day nerves, they do what every coach and dietitian will tell them not to, which is “don’t try anything new on race day!”
Sometimes this results in a negative experience leaving them feeling too nervous to try again or believing they have intolerance to the gels. Often this is due to the factors listed above with inadequate fluid or having high of a feeding rate, but there is also growing evidence showing that ‘training your gut’ is a real and impactful strategy.
A recent study (2017) conducted by Monash University on runners demonstrated the adaptability of the gastrointestinal tact and the impact of a 2 week ‘gut training’ protocol. After just 2 weeks of consuming carbohydrate during their training they found a 60% decrease in gastrointestinal symptoms and a 5% performance improvement measured in run time. Enhanced blood glucose availability and absorption was a major contributing factor.
Consuming nutrition during training (sessions longer than 60-90 mins) enhances the quality of your sessions (by allowing you to work harder, longer), supports a speedy recovery, resulting in faster adaptations or results but can also improve your race day performance and comfort.


Caffeine is known to provide a performance benefit to some athletes via its influence on the central nervous system, resulting in a reduced perception of effort (feel “easier”) and/or a reduced perception or masking of fatigue. This can be valuable in sports that require focus and concentration such as team and ball sports as well as cycling where there is heavy reliance on decision making.
The downside is that caffeine also acts as a diuretic that can increase risk of dehydration if fluid intake is not adequate.
Caffeine also has a laxative effect in the way it speeds up transit time. Caffeine sensitivity will vary amongst individuals. Having a cup of coffee, may help some have a bowel movement before you run, if you have given it time. Conversely, having too much before or during you run can increase feelings or irritability and anxiety, another contributor to runner trots.
If you choose to include caffeine make sure you start with low, measurable doses and practice in your race plan in training! Make sure you check the caffeine contents of your gels and sports nutrition as many contain caffeine. Know how much and how often you can tolerate so you can formulate your plan. Be cautious not to ignore other dietary sources of caffeine such as energy drinks, chocolate and black tea. Too much caffeine also effects sleep quality, a vital factor for performance and recovery from training.


Eating a large meal too close before your run will not allow proper time for digestion to take place and lead to gastrointestinal upset. The amounts and types of foods people can tolerate will vary. Most people will be able to eat a main meal containing low GI carbohydrates 2-4 hours before and a smaller carbohydrate rich, easy to digest snack 1-2 hours before.
If you lack the time i.e. it’s an early morning run, opt for a small carbohydrate rich snack. A ripe banana, piece of white toast with honey or jam 30-60 minutes before or a sports drink or gel 15 minutes before may work for you. The difference is dependent on the volume, and how little digestion is required.
Your fuel priorities are carbohydrate rich and having a high GI. This means it will have minimal fibre, fat or protein as these require longer digestion time and will produce greater waste or “bulk”.

Types of foods eaten

Protein, fat and fibre all require greater time to digest and form wastage. These foods are best avoided during runs unless consumed in very small amounts e.g. a 45g Pro4mance energy bar providing 30g of carbohydrates and approximately 3g each of fibre, protein and fat. An energy bar may be a preferred source of nutrition during ultra-endurance runs where intensity is characteristically a little lower allowing for better digestion while simultaneously assisting in meeting addional national needs factoring in the longer duration. These bars will often be used in combination with gels and also a preference to help curb hunger.
For moderate to high intensity running the most efficient fuel source will be simple carbohydrates such as specially formulated sports drinks and gels. They also have the advantage of helping to meet fluid guidelines and replace electrolyte loses.

Warming up

Although not nutrition related, warming into you run or training session slowly rather than jumping straight into high intensity work or fast running can help prevent GI issues. A good warm up with dynamic stretches and drills not only has benefits on performance and reducing injury risk but also allows your body to start increasing blood flow to working muscles and adjusting fuel sources with hormonal fluctuations.

Personalised Training and Race Day Plans

If you would benefit from a tailored daily nutrition, training and racing nutrition program for your next running, cycling, swimming or triathlon event click on this link to make a face to face or online (phone/skype) appointment. My aim is always to empower you to achieve your goals with the knowledge, understanding, support and plan!

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