The Effects Of Extreme Exercise On Digestion

The Effects Of Extreme Exercise On Digestion

Common negative effects include acid reflux, heartburn, nausea, vomiting, dehydration abdominal cramps, urgent defecation diarrhoea and bleeding from the rectum

Though we continuously harp on the positive aspects of exercise, it should also be known that exercise can have some negative effects and especially on the digestive system. However, the intensity of the negative effects of extreme exercise varies from person to person.

Moderate intensity exercises may not have significant negative effects on digestion but during high intensity exercises, a third of the participants may suffer from the symptoms of mal-absorption, mal-digestion, altered gut transit or improper fluid and food intake before or during exercise. However these symptoms are generally transient and do not have long-term consequences.

Also, the symptoms are more common in runners than swimmers or cyclists and elite athletes are more likely to have the symptoms than recreational athletes, The intestine is not an athlete’s organ, in the sense that it adapts to exercise-induced physiologic stress. During exercise, blood is selectively diverted towards exercising muscles and lungs.

Common negative effects include acid reflux, heartburn, nausea, vomiting, dehydration, abdominal cramps, urgent defecation, diarrhoea and bleeding from the rectum. The bleeding from the rectum is generally minor but can also be severe. But gradual programming of exercise with respect to intensity and duration may ameliorate some of the harmful effects of exercise.


This is possibly the most common negative effect of prolonged heavy exercise seen in nearly a third of exercisers. Exercising while standing. relaxes the lower oesophageal sphincter, allowing acid reflux from stomach into the food pipe causing heartburn.

This can be prevented by exercising on an empty stomach. Persistent symptoms can be successfully treated with drugs like omeprazone and patroprazole, but long-term treatment may be required it intense exercise is continued.

Nausea/Vomiting Nausea occurs at the peak of heavy exercise, due to diversion of the blood from the gut to the muscles, leading to some degree of gut ischemia noted in a significant percentage of athletes. But this is generally transient, self- limiting and settles down once the seventy of exercise is reduced. It can be prevented by exercising on an empty stomach.


Dehydration is common in prolonged exercising, particularly during hot weather as the fluid requirement increases. Hydrating the body several hours before exercising and drinking plenty of water during the exercise helps fight dehydration. Gradual training with regard to the severity and duration of exercise over months, leads to better adaption of the body to the degree of dehydration.

Abdominal Pain/Stitch

Abdominal pain caused by exercising, known as a stitch.’ is well-known to those who do intense exercise, It is more common in those who frequently move their upper body like n, horse riding and running. The pain occurs laterally in the mid-abdomen just below the costal margin, but it may vary.

Abdominal pain can be prevented by avoiding eating and drinking too much a few hours prior to exercise, improving posture and supporting the abdominal organs by improving core strength or wearing a supportive broad belt. During prolonged rigorous exercise, be careful about taking an antispasmodic (pain killer) or antimotility agent like buscopan (hyocimax) or colimax. Because, consuming these can lead to an inability to control core body temperature by inhibiting perspiration, which can be dangerous.

Rectal Bleeding

Exercising for prolonged periods of time, can lead to severe reduction in blood supply to the gut, causing gut ischemia which is the cause of bleeding from the gut mucosa. This is generally mild and self limiting if the exercise is terminated at the beginning of the symptom.

Profuse bleeding requiring hospitalization, blood transfusion or surgery rarely occurs but if it does, it can even be life-threatening. This can be prevented with better hydration before and during exercise and gradual build-up of stamina. Some athletes are prone to this complication, hence they should always keep themselves well hydrated and terminate exercising if they have rectal bleeding.


Defecation Urgent defecation is seen in a significant number of exercisers at the peak of the exercise as the gut transit time is markedly reduced during prolonged exercising. Reduced blood flow leads to decreased absorption of nutrients and impaired water reabsorption in the large gut resulting in diarrhoea.

This is partly preventable by proper hydration before and during the exercise, reducing fibre intake and avoiding solid foods several hours before the exercise. Visiting the toilet just before exercising is advisable.

Sweetened sports drinks may cause diarrhoea in those who are intolerant to fructose. Taking loperamidekidol, an antimotility drug, available over-the counter helps control diarrhoea and decrease stool frequency when taken prior to exercising.

Leave a Comment