Sport & Exercise

Exercise induced gastrointestinal syndrome- are you at risk?

Exercise is widely promoted in public health policy as being good for our mental and physical health and usually it is.

In our relatively sedentary 21st century existence, exercise is seen as a way for people to strengthen their musculoskeletal and cardiovascular health and as a means to prevent and manage non-communicable diseases such as diabetes, obesity and heart disease.  Exercise also encourages people to get out into their community, to enjoy their environment and maybe join others in group exercise activities.

While every bit of exercise does accrue health benefits in this way the duration and intensity of exercise can be very important and for some people the strain of exercise may compromise the function of the gastrointestinal tract and lead to gastrointestinal symptoms.

Now known as “exercise induced gastrointestinal syndrome” it’s symptoms can affect the upper intestinal tract such as heartburn, reflux, nausea and vomiting or lower GI tract such as bloating, flatulence, diarrhoea, abdominal pain and cramping.1

There has been a lot of research recently around the effects of endurance and ultra-endurance exercise, on the gut health of athletes as more of them report the gut health problems they are facing. There is also a growing awareness that some people may have a greater pre-disposition than others to gut health problems which may be aggravated by untoward exercise strain.2-4

One common example of this is “Runner’s Trots”, when sometimes athletes experience an overwhelming need to defecate while running.

Diarrhoea, along with other signs of gastrointestinal distress caused by the physical motion of exercise, affects athletes involved in endurance and long distance running and cycling, events, especially those lasting more than 2 hours in hot or humid conditions at high intensity (i.e>60%  VO2 max).1

There are several reasons attributed to this occurring:

  • Heat stress, when blood is directed away from the gut to skeletal muscles and the body’s peripheral circulation, can have the effect of impairing gastric emptying times, reducing the ability to digest and absorb nutrients and the gut lining can be left more permeable and prone to inflammation and injury1, 5.
  • The jarring action of running jolts the GI tract organs against the abdominal wall which may increase the sense of urgency and need for the athlete to break for a toilet stop.
  • The body position of the athlete during exercise may cause discomfort. Cyclist (especially if adopting the hunched ‘aero’ position) and rowers may find their confined space in the boat, compresses their abdomen, increasing the urge to defecate compared to other athletes.
  • Female athletes are more likely to experience exercise induced gastrointestinal syndrome than males.
  • Some individuals with recurrent symptoms of this syndrome may have a greater predisposition to its occurrence.
  • Feeding during exercise when the gastrointestinal tract may already be compromised may be a risk factor for some athletes.

While these symptoms are very individual they can be stressful and interrupt an athletes ability to train and temporarily alter the absorption of key nutrients. So if this is affecting you let’s consider some of the dietary factors that may help to alleviate some of the problems.

  • Avoid dehydration and also drinks with a high carbohydrate concentration (>10%) such as energy drinks or fruit juice. Sports drinks with a lower 4-8% carbohydrate concentration or water are preferable.
  • Carbonated drinks (including sparkling mineral water) can increase bloated feelings and abdominal pain, so are best avoided.
  • Avoid eating main meals too close to the event allow 2-4 hrs before eating and exercise.
  • Mind the type of foods that you eat pre-event. High fat and high protein foods delay emptying of the stomach which can cause gastro-intestinal upset. While normally an athlete may eat good sources of dietary fibre day to day, on event days and in 2 days pre-event more refined forms of carbohydrate may sit more comfortably in the gut. Do practice this before adopting for main events.
  • People with gut related medical problems, such as Coeliac disease, Irritable bowel syndrome, Lactose or fructose intolerance as well as some people with allergies, may find that exercise compounds their symptoms. Affected athletes may need to refine their meal plans with a Sports Dietitian.
  • The adoption of gluten free diets by non-coeliac athletes is so far not supported by blinded control study however some athletes may benefit from the short- term use low FODMAP diets to reduce exercise induced gastrointestinal symptoms.6
  • Research to improve nutrient absorption during endurance events has found gut training using carbohydrate can help.

This information is just some of the topics covered in my new book “How to grow an athlete- from playground to podium” out soon.

If this topic is relevant to you, a friend or family member and you would like personal help then contact me, for a nutritional assessment and advice that could aid your performance and reduce health risks.


  1. Costa, R.J.S., Snipe, R.M.J., Kitic, C.M., Glibson, P.R., ‘Systematic review: exercise-induced gastrointestinal syndrome – implications for health and intestinal disease’, Alimentary Pharmacology and Therapeutics, 2017, 46(3), 246–65.
  2. Costa RJS, Snipe R, Camões‐Costa V, Scheer BV, Murray A.  The impact of gastrointestinal symptoms and dermatological injuries on nutritional intake and hydration status during ultramarathon events. Sports MedOpen. 2016; 2: 1‐ 14.
  3. Jeukendrup AE, Vet‐Joop K, Sturk A, et al.  Relationship between gastro‐intestinal complaints and endotoxaemia, cytokine release and the acute‐phase reaction during and after a long‐distance triathlon in highly trained men. Clin Sci. 2000; 98: 47‐ 55
  4. Stuempfle KJ, Hoffman MD.  Gastrointestinal distress is common during a 161‐km ultramarathon. J Sports Sci. 2015; 33: 1814‐ 1821.
  5. van Wijck K, Lenaerts K, Grootjans J, et al.  Physiology and pathophysiology of splanchnic hypoperfusion and intestinal injury during exercise: strategies for evaluation and preventions. Am J Physiol. 2012; 303: G155‐G168.
  6. The FODMAP Diet ‘Shepherd Works’,


Other articles by Lea on similar topics

How to help athletes recognize the mental health risks of sport

The gut-brain axis is important to sporting performance

6 Tips for helping athletes eat more plant foods

Are you eating enough to build strength?

Alcohol and sport is it a good match for you?

Is going Gluten Free a healthy food choice?

What’s the fuss about fructose?

About the author View all

Lea Stening

Lea is one of New Zealand’s leading paediatric dietitians and also specialises in Sports Nutrition. She has specialised in Paediatric Nutrition for 31 years and in 1985 was the first paediatric dietitian to enter private practice in New Zealand. Lea helps families through her private consultations, public lectures, newspaper and magazine articles as well as television and radio interviews. Read more »

View all posts by Lea Stening »


Leave a Reply

Also in Sport & Exercise View all »

  • Carbohydrate for body growth and repair

    Protein provides the building blocks of amino acids to allow for muscle mass and tissue repair, but it is the carbs that fuel this body building process. Encouraging people to control,not cut, their carbohydrate can be a challenge. Read more »

  • How to stay an athlete and enjoy active aging

    Exercise and age are both stressors on the body, but with the correct diet and exercise we can adapt, remodel our body and maintain a high level of fitness (at any age) if we are prepared to put in the effort, long-term. Read more »

  • The protein needs of young athletes

    At a time when they are also growing, young athletes may need as much as 50% more protein than their more sedentary peers. So should this extra protein be consumed from whole foods or supplements? Learn more... Read more »

  • How to Grow an Athlete: From Playground to...

    It's finally out Lea's latest sports nutrition book for children How to Grow an Athlete: From Playground to Podium is available to buy from NZ booksellers and directly from Lea. To learn more listen to Lea's interview with RNZ Read more »

  • Milk is a valuable sports nutrition supplement

    Whether you are an athlete wanting to improve your performance or just keen to improve your level of fitness, interest is growing in the use of milk as a sports supplement that is good for your health at any age. Read more »

  • 6 reasons to control, not cut your carbohydrate...

    Are you needing to lose or gain weight, control blood pressure, reduce insulin resistance, diabetes, PCOS or heart disease? Dietitians recommend that controlling rather than cutting your carbos, can provide many health benefits. Read more »

  • Use nutrition knowledge to empower you to a...

    How do you learn & where does your nutrition information come from? How much do you eat to stay well & to fund changes in activity levels? What beliefs & attitudes prevent you from making better food choices? Learn more Read more »

  • Are you energy deficient?

    Energy deficiency is more common than you may think and can be found in our hospitals, schools and kindergartens, rest homes and on our sports fields. It can affect over and underweight people. Are you at risk? Read more »

  • Nutrition updates may assist Master’s...

    Athletes over 35 years old are mostly in the Master's category. Their energy and nutrient needs change with age and the level and type of sport being undertaken. Refreshing their nutritional knowledge can improve performance Read more »

  • Vitamin D for growth and immunity

    Recent research has highlighted the importance of vitamin D to respiratory health with those who are deficient being 5 times more likely to contract Covid-19. It is important for children, athletes and the elderly. Find out why? Read more »

  • Nutrition and eye health

    Good vision is essential for good health and sporting performance, especially if athletes are involved in precision sports that require good hand and eye co-ordination such as tennis, archery, pistol shooting, cricket and golf. Read more »

  • How to help athletes recognise the mental health...

    Unlike a broken leg, mental health illness is something we can not see. Even athletes may discount their fatigue or depression as just due to training. Find out how to help. Read more »

  • Retiring athletes may need to rethink their...

    Retirement from sport can happen at any age, in any code and any level of expertise. For many athletes it can mark an important transition in life and lead to better nutrition. Read more »

  • Sleep for better self-regulation and diet

    Are you getting enough sleep? Studies have shown that a chronic lack of sleep can have a major impact on our nutritional well- being, our mental and physical health. Read more »

  • Can caffeine improve your performance?

    New Zealand ranks 13th in the world for coffee consumption ahead of Australia and USA. What are the effects of caffeine on our health and can it improve our performance? Read more »

  • 6 Tips for helping athletes eat more plant...

    If we are to adopt a more plant based diet how will athletes meet their nutritional needs for protein, energy and vital nutrients? Here we offer some 6 tips on how to increase vegetable intake for better performance. Read more »

  • Are you eating enough to build strength?

    For many people strength and conditioning is their passport to better looks, confidence and performance. What are the nutritional issues? Read more »

  • Iron makes us happy- are you getting enough?

    Iron is important for happiness because without it our moods change and physical performance deteriorates. Are you getting enough? Read more »

  • Alcohol and sport- Is it a good match for you?

    When used responsibly alcohol can help to relieve tensions in athletes and to build feelings of inclusiveness in a team. However in excess it can slowly unravel training, health and sporting careers. Read more »

  • How do we ‘grow’ an athlete in...

    To 'grow' a healthy athlete it takes a combination of genetics, training, hard work, good coaching, time and most of all the 'right' food. Read on and learn how. Read more »

  • Would activity icon labels alter your food...

    Obesity is a global problem we need fresh ideas to help to solve. UK studies of icon labelling suggest this could be a popular initiative Read more »

  • Time your eating for better performance?

    If playing sport or exercising, understanding the GI can help you to select foods that will provide optimal energy at key stages of activity for better performance. Read more »

  • Orthorexia Nervosa: When healthy eating can...

    An Orthorexics daily obsession with obtaining healthy eating can reduce time available for other interests that formerly made up the fabric of their life. Help is available. Read more »

  • What’s to drink?

    As concern, regarding the sugar and energy content of carbonated drinks and fruit juice, gathers momentum many people are looking for alternative drinks to have. Read more »

  • Is going “Gluten Free” a healthy...

    As the popularity of gluten- free diets grow we need to question whether in fact it is a healthy option for any of us and if not how can we make it so? Read more »

  • Sports supplements should be taken with care

    While some supplements are well recognised as being useful to performance others can lead to positive drug testing and disqualification as well as endanger long-term health. Read more »

  • Don’t let stress fractures slow your...

    Stress fractures are not just a problem for athletes who overtrain. They can affect anybody as they also relate to lifestyle and nutrition choices. Find out if you at risk. Read more »

  • Nutrition for distance runners and “fun runs”

    Distance running and “fun runs” (and walks) of varying length and degree of difficulty are becoming popular, attracting family and community groups; recreational and elite participants. Paying attention to sports nutrition can improve an athletes performance and enjoyment of these events Read more »

  • Taste is important to fluid consumption

    Taste is an important factor affecting fluid choice and level of consumption and therefore is an important consideration to overall sporting performance Read more »

  • Muesli and sports bars can aid performance

    Muesli and sports bars are designed to provide a convenient source of energy to be thrown into a lunchbox, gym bag or pocket and eaten “on the run”. However if eaten daily as a “lolly” or relied on as a meal replacement they can lead to unnecessary weight gain. If used wisely during training and competition they can provide athletes with a measured source of carbohydrate vital to performance. Read more »

  • Food planning is important for hiking safety

    Research does show more injuries occur in the mid-late afternoon in open country than other times of day. This is often when people become dehydrated, their muscle levels of energy (glycogen) can become depleted and blood glucose levels may be falling, all factors which lead to fatigue Read more »

  • Dietary help for depressed athletes

    Although athletes may benefit from an exhilarating endorphin rush on exertion that elevates their mood and suppresses feelings of pain it will not stop them from experiencing, at times, anxiety and bouts of depression just like the rest of us. Nutrition is one treatment option that can speed recovery. Read more »

  • Diet can offer protection when cold conditions...

    Cold injuries and illness occur in a wide range of physical activities. An understanding of the importance of sports nutrition and planning appropriate meals and snacks can offer some protection and may also improve overall performance Read more »

  • Can a high fat diet improve sports performance?

    Fat carries more energy than other macro nutrients (9kcals/37kJ/g compared to 7kcal/29kJ/g for alcohol and 4kcal/17kJ/g for protein and carbohydrate respectively). So with so much energy to offer does eating more improve performance? Read more »

  • Vegetarians face extra hurdles

    Despite the apparently healthier lifestyle vegetarian athletes (like anybody) can still become overweight, hungry, bloated and suffering from multiple nutrient deficiencies. Read more »

  • The gut-brain axis is important to sporting...

    Do you ever suffer from” runners diarrhoea”, bouts of anxiety , fatigue, abdominal pain or gas when facing competition? Read more »

  • Swim for your life

    Whether you are swimming for fun or competition this sport has many health benefits that can be enhanced with good nutrition. Knowing what to eat and when can also greatly improve your enjoyment of the sport as well as your level of performance. Read more »

  • Skin care for active people

    The stress of competition, the sun and wind, sweat, chaffing and high sugar levels are just some of the things that can aggravate the skin conditions of athletes and very active people. Read more »

  • Don’t let disordered eating ruin your...

    An eating disorder can affect anyone at any age, any sport, any background and any gender. The symptoms may build slowly well before the illness becomes evident. Often it is an athletes support team such as parents, friends, team mates and coaches that pick up on the symptoms and can prevent the disorder from ruining the athletes sporting career. Read more »

  • Put Sports Nutrition to work

    Many workers use enough energy and essential nutrients each day to power a marathon. If not replaced then a lack of these key nutrients can lead to fatigue, accidents and injury that can affect their long-term health and mobility. Read more »

  • Athletes protect your winning smile

    Athletes protect your smile and your wallet as painful tooth erosion is not only expensive it can also rob your training time and performance. Read more »

  • What are our children drinking?

    In 2015 New Zealanders consumed a total of 518 million liters of carbonated drinks. Outside of the drinking of milk and water there is real concern about the energy content of some of these beverages because of our rising incidence of diabetes and obesity. Read more »

  • Facing the down times without weight gain

    Nothing can be more infuriating for an athlete than after months of intense training an injury sees you ‘sidelined’. Read more »

  • Sports nutrition for women

    Women who push the boundaries of their lives to take on new challenges and sporting events are usually also trying to juggle their work, home and training existence. With good sports nutrition advice It is possible to find renewed energy. Read more »

  • Sports nutrition for cycling

    Cycling tests an athlete’s strength and endurance capabilities as well as their anaerobic energy systems during breakaways, hill climbs and sprints to the finish.While some athletes rely heavily on dietary supplements, these will not replace a healthy training diet that is high in carbohydrate, with moderate protein and low in fat. Read more »

  • Food to Fuel the Speights Coast to Coast

    Whether you are a novice or seasoned triathlete your nutrition plan could make or break your race. All those competing should read the excellent nutrition tips on the official Speight’s Coast to Coast website and seek professional help if they have any concerns. In addition here is a check list of things you should also consider. Read more »

  • Nutrition for tendons and ligaments

    The recent Rugby World Cup has placed the spot light on sports injuries and so we thought it might be interesting to look more closely at the protective role of sports nutrition and in particularly the nutrients important to tendon and ligament health. Read more »

  • Tips to move you off the couch

    Are you wanting to get into exercise but are finding every excuse under the sun? E.g. my neighbour wants to join me but is away right now; I’m waiting for the gym to open; I’ll get back into it when school goes back. Does this sound familiar? If you wait for all the conditions to … Read more »

  • Dehydration and young athletes

    Young children and adolescents are not little adults – dehydration can be a real problem for young athletes. Find out why? Read more »

  • Motivation to keep training

    Whether you are training for a national event or simply trying to keep fit and healthy here are some tips that may help you get into gear: Read more »

  • What is the “Exercise Price” for...

    Find out how much exercise you may need to do to burn off those extra Easter calories Read more »

  • Diet may help exercise induced Asthma

    Exercise induced asthma (EIA) occurs in approximately 90% of people with asthma.Traditionally it has been treated with medication. However, there is now convincing evidence that a variety of dietary factors can also be of help: Omega-3 polyunsaturated fatty acids in the form of fish oil Antioxidants in particular flavones which are to be found in … Read more »

  • Exercise and pregnancy

    If exercising during pregnancy, what are the risks and what forms of exercise are the safest to undertake? Read more »

  • Walk more sit less

    Take up the challenge! If you want to loose weight and get fitter you have to walk more and sit less right now. It has been estimated that if everyone in the USA were to walk briskly 30mins each day they could reduce chronic illness by up to 40%. If we did the same we … Read more »

  • Issues of concern to young athletes

    Young developing athletes are an incredibly challenging group to work with because they are usually in the middle of adolescence and experiencing considerable physical and emotional change. Read more »

  • Sports nutrition issues to consider for the...

    If you are planning to take a team to an Olympic games or you plan to compete yourself then there are a number of issues you may like to consider in order to maximise performance and preserve good health. Read more »

  • Water intoxification!

    It is possible to drink too much. Athletes in particular can be at risk of developing hypernatraemia so are advised to check their hydration plans with us before embarking on endurance events. Read more »

  • 10,000 steps Rockhampton

    The general population is becoming more aware of the health risks associated with an inactive lifestyle, however the major task is to find innovative approaches to encourage a more active lifestyle for everyone. Projects like the 10,000 steps Rockhampton program may be just the thing we need! Read more »

  • Active young adults reap cardiovascular benefits...

    Those who enter adulthood with a good level of cardiovascular fitness have been found to be least likely to develop cardiovascular risk factors such as high blood pressure, diabetes and even metabolic syndrome later in life. Read more »

  • Sports nutrition for triathletes

    Ideally, experienced athletes will have started preparing months before their major event with an improvement in their baseline nutrition for body maintenance. Read more »

Would you like to subscribe to our fantastic FREE monthly newsletter?

Each month we'll keep you up-to-date with the latest nutritional articles and healthy recipes from You are free to opt out at any time, but we think you'll enjoy what we've got in-store for you.

Plus as a bonus offer — subscribe today and receive FREE weight loss tips for two weeks! Learn how a number of foods, many one would consider 'healthy', may in fact be slowing your progress.


Yes please, it sounds great! (and it's FREE after all).



No thanks, I'm not interested (or I'm already a subscriber and really enjoying these fantastic newsletters!).