How to Reduce Gastrointestinal Problems in Long Distance Runners

According to a study published in Runner's World, running can compromise the digestive system, which can lead to nausea or even vomiting, especially if the person runs too soon after eating or drinks too much water. And we know that there are runners who are prone to precisely this type of discomfort.

It is important to understand the effects of long-distance exercise on the body and how it can affect the digestive system. In the case of long-distance running modalities, whether they are asphalt modalities (such as a marathon), trail running or long distance triathlon such as for example the Ironman, problems can be common gastrointestinal, such as nausea and vomiting.

These problems not only impair the runner's performance, but also put their health at risk.

Causes of gastrointestinal problems in long-distance runners

There are two areas where we must focus our attention to understand and solve these gastrointestinal problems:

  1. Firstly, those related to the physiology of sport, that is, the processes that take place in the human body as a result of physical activity. During prolonged exercise, blood is bypassed from internal organs, including the stomach and intestines, to active muscles. This can lead to decreased gastrointestinal motility and a buildup of food and fluid in the stomach, which can cause nausea and vomiting. On the other hand, the physical and emotional stress of prolonged exercise can increase the production of stress hormones, such as adrenaline and cortisol, which can affect gastrointestinal function and cause nausea and vomiting. Finally running causes continuous impacts on our physiological system and on the organs of the runners, which in turn cause small tears in the intestinal walls that compromise the absorption of nutrients.
  2. Secondly, and precisely because our digestive system will be significantly compromised during a long-distance race, we must pay special attention to all those sports nutrition supplements that we are going to take before and after the race. It is essential that these sports supplements are developed according to the physiology of sports and that, therefore, they are easy to assimilate by our digestive system.

These are our keys to avoid gastrointestinal problems in long-distance running modalities.

The combination of quality carbohydrates, key to facilitating the assimilation of nutrients and avoiding discomfort

Precisely because our digestive system is compromised during exertion, it is essential that all energy gels, bars, isotonic drinks and other energy supplements are formulated with mixtures of different carbohydrates (of different glycemic indices and always high quality).

In Herooj, following the scientific knowledge of our physiologists, we formulated the Seawater Energy Hydrogels, with a studied combination of 5 carbohydrates (both complex and rapidly absorbed sugars) with glucose-fructose ratio 2:1 that does not saturate the different absorption pathways of the digestive system (and promotes correct gastric emptying). This saturation is generally the main reason for gastrointestinal problems or discomfort that athletes experience when they ingest energy gels.

The combination of complex carbohydrates and fast-absorbing sugars not only makes the runner feel better, but provides sustained and sequential energy:

  1. A first “boost” of energy to be able to maintain performance thanks to fast-absorbing sugars (with an almost immediate digestion time).
  2. The obtaining of energy in a staggered and sustained manner over time thanks to the different carbohydrates introduced into the gel, which will be digested at different speeds due to the number of links present in its molecular structure.

This will offer us the possibility of having the necessary energy “fuel” for much longer without suffering from rebound hypoglycemia or, as they are commonly known, the “birds”, which occur with other products that do not offer this spectrum of sugars and carbohydrates and that cause feelings of fatigue and lack of motivation during physical activity.

Hydrate properly, better with minerals and trace elements of marine origin

Minerals of marine origin, such as sodium, magnesium and calcium, are important for hydration and electrolyte balance, which may be beneficial in reducing the risk of nausea and vomiting during prolonged exercise.

At a technical level, as various physiologists experts in the field have well pointed out, including seawater as a key ingredient in sports nutrition products, marks a before and an after in the performance of the athlete.

Sea water is made up of the widest spectrum of minerals, up to 75 different types. Although it is true that there are minerals of marine origin that are more important when we talk about long distance:

  • Sodium: Sodium is an essential mineral for hydration and electrolyte balance. Long-distance athletes can lose large amounts of sodium through sweat, which can lead to dehydration and performance problems. Sodium intake during prolonged exercise can help maintain electrolyte balance and improve hydration.
  • Magnesium: Magnesium is an essential mineral for muscle function and energy production. Long-distance athletes may be at increased risk of magnesium deficiency due to increased muscle demand and loss of magnesium through sweat. Magnesium supplementation may help improve muscle function and reduce the risk of muscle cramps.
  • Potassium: is one of the minerals that improves communication between nerves and muscles, which can help prevent cramps and muscle aches. It also regulates blood pressure and heart rate.

    For this reason, at Herooj we include essential amounts to optimize the athlete's performance, as in the case of Seawater Energy Hydrogels , which contain: 56mg of magnesium, 164mg of sodium and 24mg of potassium per unit.

    Train the digestive system, both at the sports nutrition level and at the microbiota level

    One of the keys to avoiding discomfort is training the digestive system. Not only at the level of sports nutrition (avoiding as far as possible trying new things in the race), but also at a deeper level. Endurance athletes can benefit from optimizing the intake of gut-healthy carbohydrates.

    As various sports nutrition professionals have well studied, ethere is evidence that exercise promotes changes in intestinal structure, although this seems to vary greatly depending on the intensity, mode and time of the exercise (1,2).

    In one of the most exciting recent investigations, Barton and colleagues used a case study approach, tracking the gut microbiota of two sedentary male humans as they embarked on a 6-week training program. months for an Olympic distance marathon or triathlon (3). As the training progressed, so did the participant's body composition and fitness parameters. Increases in gut microbiota diversity (a characteristic associated with health) occurred with sustained training. Participants exhibited a higher abundance of microbial species that have been shown to influence short-chain fatty acid (SCFA) production. SCFAs act as fuel substrates that have been shown to be absorbed and used by the body in muscle tissue (7). However, the increase in these SCFA-producing microbes was not reflected in actual SCFA levels.

    Physical exercise thus appears to alter the structure of the gut microbiota, with some clear evidence that it increases the overall diversity of bacteria harboring the SCFA gut flora .

    A concept that is used to study the relationship between intestinal health, sport and carbohydrates are carbohydrates accessible to the microbiota, or MAC for short.

    MAC are carbohydrates that are not metabolized by the athlete and are therefore available for metabolism by the microbiota. Diets low in MAC appear to promote the growth of bacteria that degrade the mucosal lining around the intestinal barrier (5). This can affect the integrity of the barrier and cause problems. However, not everyone can respond well to a MAC-rich diet right away. Common side effects can include bloating and gas (6). If your diet is low in MAC, it is best to slowly increase these foods over time. And, very important, not near competitions or long-distance training, you have to train it beforehand. So a positive strategy may be for athletes to supplement their diet with carbohydrates that are accessible to the microbiota, which can help encourage microbiota growth associated with good health. Another potential strategy could be the intake of fermented foods and probiotics, together with minerals of marine origin and essential macronutrients.

    In order to train the digestive system in a direct way with probiotics and prebiotics essential for the proper functioning of the intestinal flora, Herooj has formulated Immunosport Microbiotics. With more than 5 bacterial strains, it not only seeks to strengthen the digestive system, but also to prepare the intestinal mucosa to absorb all the nutrients.

    And it is that a correct structure of the microbiota is directly related to better performance, better recovery and a lower incidence of pathologies or diseases. Over time, as fitness improves, it may be that the restructuring of the microbial community better serves the athlete's performance by providing fuel, rather than assimilate nutrients correctly and help the metabolism of exercise. However, to support these changes, a balanced diet will be essential

    Taking care of the digestive system both during the race and preventively, key to improving performance and minimizing discomfort

    Proper nutrition and especially adequate sports supplementation will be beneficial for long-distance runners. A supplementation that combines natural ingredients, essential macronutrients and well-balanced minerals of marine origin, can provide a sustainable source of energy, improve physical performance and reduce the risk of gastrointestinal problems. In addition, as we have seen, it is necessary to take care of our digestive system and microbiota through the different strategies mentioned.


    1. Asker Jeukendrup (online) - Can the gut microbiota be trained? https://www. mysportscience. com/post/athletic-gut-microbiota-part-2

    2. Mohr AE, Jäger R, Carpenter KC, Kerksick CM, Purpura M, Townsend JR, West NP, Black K, Gleeson M, Pyne DB, Wells SD, Arent SM, Kreider RB, Campbell BI, Bannock L, Scheiman J, Wissent CJ , Pane M, Kalman DS, Pugh JN, Ortega-Santos CP, Ter Haar JA, Arciero PJ, Antonio J. The athletic gut microbiota. J Int Soc Sports Nutr. 2020 May 12; 17(1):24. doi: 10. 1186/s12970-020-00353-w.

    3. Barton W, Cronin O, Garcia-Perez I, Whiston R, Holmes E, Woods T, Molloy CB, Molloy MG, Shanahan F, Cotter PD, O'Sullivan O. The effects of sustained fitness improvement on the gut microbiome: a longitudinal study, repeated measures case study approach. Transl Sports Med. 2021 March;4(2):174-192. doi: 10. 1002/tsm2. 215.

    4. Pugh JN, Kirk B, Fearn R, Morton JP, Close GL. Prevalence, severity, and possible nutritional causes of gastrointestinal symptoms during a marathon in recreational runners. Nutrients. 2018 June 24; 10(7):811. doi: 10. 3390/nu10070811.

    5. Daien CI, Pinget GV, Tan JK, Macia L. Detrimental impact of microbiota-accessible carbohydrate-deprived diet on gut and immune homeostasis: an overview. Front. Immunol. 2017; 8:548.

    6. Burke, L. m , & Hawley, J. TO (2018). Swifter, higher, stronger: what's on the menu?. Science, 362(6416), 781-787. doi: 10. 1126/science. aau2093

    7. Jeukendrup A. (2017). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine, 47(Suppl 1), 7-16. doi: 10. 1007/s40279-017-0694-1

    8. Jouris, K. B. , McDaniel, J. L , & Weiss, E. P (2011). The effect of Omega-3 fatty acid supplementation on the inflammatory response to eccentric strength exercise. Journal of Sports Science and Medicine, 10(3), 432-438.

    9. Maughan, R. J , Burke, L. m , Dvorak, J. , Larson-Meyer, D. AND , Peeling, P. , Phillips, S. m , Engebretsen, L. (2018). IOC consensus statement: dietary supplements and the high-performance athlete. British Journal of Sports Medicine, 52(7), 439-455. doi: 10. 1136/bjsports-2018-099027

    10. Niemann, D. C. , & Mitmesser, S. h (2017). Potential impact of nutrition on immune system recovery from heavy exertion: a metabolomics perspective. Nutrients, 9(5), 513. doi: 10. 3390/nu9050513

    11. Nielsen, F. h , & Lukaski, H. C. (2006). Update on the relationship between magnesium and exercise. Magnesium Research, 19(3), 180-189.

    leave a comment

    Please note that comments must be approved before being published.

    This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.