Exercise is good for us, yes? With its wide range of benefits, including supporting heart, gut, muscle, and bone health, the short answer is yes. But could there be repercussions for over-exercising? Some people say intense exercise can lead to a leaky gut. It refers to as exercise-induced gut permeability in literature. The mechanism for damage stems from changes in blood flow and neuronal functioning. Blood flow diverts from the intestinal tract during exercise. Also, changes in the nervous system work to decrease intestinal motility. Our bodies move the resources to the arms and legs and away from the gastrointestinal (GI) tract.
Similarly, the stress of any kind can exacerbate a leaky gut for the same reason. Adrenal hormones move resources away from the GI tract and into skeletal muscle, away from the intestines. In addition, any stress can cause oxidative damage.
The concept of a leaky gut has slowly infiltrated traditional medical circles. A recent article sums up the current opinion. But there is a growing body of literature characterizing the nature of leaky gut. Many practitioners see it as the underlying cause of chronic fatigue syndrome, multiple sclerosis, fibromyalgia, thyroid abnormalities, and many more.
The material within the intestines is technically outside our bodies and must remain there for proper functioning. The GI tract acts as a gatekeeper. It allows nutrients into the body and keeps toxins and microorganisms out. More than half of the immune system is near the GI tract, protecting us from foreign proteins and microorganisms. A leaky gut is where things are usually kept out of the body by intact GI mucosa. As a result, a leaky gut may put your immune system in overdrive as the body must address foreign invaders.
Changes in the GI tract during exercise can create or exacerbate symptoms like:
Nausea
Regurgitation
Belching
Side stitch
Abdominal cramps
Urge to defecate
Flatulence
Stomach pain
Gastric acidosis
Abdominal pain
Constipation
Heartburn
Reflux
Bloody stool
Diarrhea.
In a review of published studies, the investigators found that intestinal damage and impaired function increased proportionally with the intensity of the exercise. The threshold for GI disruption was two hours at 60% VO2 max. It did not have much to do with the subject’s fitness level. In other words, being in better shape did not protect me from the adverse GI effects of intense exercise. Working out in the heat seems to exacerbate gut disturbances. The authors concluded, “Strenuous exercise has a major reversible impact on gastrointestinal integrity and function of healthy populations. The safety and health implications of prolonged strenuous exercise in patients with chronic gastrointestinal diseases/disorders, while hypothetically worrying, has not been elucidated and requires further investigation.”
Intense Exercise and GI Tract
Strategies exist, however, to mitigate the stress that intense exercise puts on the GI tract. According to Dr. Ricardo Costa, lead author of the previous review said: despite excessive exercise is confirmed to compromise gut integrity and function. We also have identified you can control several exacerbating factors. Several prevention and management strategies can attenuate and abolish the damage and compromised part of the GI tract.
Experts recommend that individuals with symptoms of gut disturbances undertake a full gut assessment during exercise during training to ascertain what is causing the issue and develop individually tailored management strategies.”
Another study looked at what could be done to protect the GI tracts of elite athletes. The double-blind, placebo-controlled study tested whether zinc carnosine and bovine colostrum (a natural source of growth factors) would help with the adverse GI effects of intense exercise on gut health. It was a crossover study, with the volunteers taking a placebo, zinc carnosine, colostrum, or a combination of zinc carnosine and colostrum before training. After exercise, body temperature increased by 20 C, and intestinal permeability increased as measured by five-hour urinary lactulose/rhamnose ratios. The authors concluded, “ZnC [zinc carnosine], taken alone or with colostrum, increased epithelial resistance and the TJ [tight junction] structure and may have value for athletes.”
Zinc carnosine and colostrum are only two substances that are useful for healthy intestinal support. It is a study of exercise and gut health that is not designed yet. Still, other GI protective substances should also be beneficial to those who exercise intensely, especially considering what Dr. Costa had to say after the findings of his study. Clinical studies show other substances such as aloe, bone broth, L-glutamine, and MSM support the health and integrity of the gastrointestinal tract.
