Imagine this… You wake up early, eager to get to the gym for a good workout sesh with your workout buddy. You’re so proud of yourself for getting up early and sticking to the plan you made the night before. You’ve got your cute (or grungy) gym outfit all picked out, and your workout routine, sneakers, water bottle, and headphones all ready to go. You have a quick snack for a little bit of extra energy, or maybe you have a pre-workout and you’re on your way. You drive to the gym and start warming up, you’re feeling great, but all of a sudden you feel this gurgling in your stomach, and realize you need to run to the bathroom. Not a pretty picture, I know, but the fact of the matter is, GI discomfort coupled with exercising is a fairly common reality for many people.
While the following is not an overly comprehensive list of what might be contributing to your GI distress surrounding exercise, it’s a good starting point when considering possible root causes:
1. Too much of the wrong kind of sugar (fructose, stevia, sugar alcohols). Digestion is one of the primary foundations in our body that must be functioning optimally for many different bodily processes to occur. However, the digestive process is very delicate, thus, there are many little things that can easily disrupt it. For example, too much of the wrong kind of sugar, such as fructose (especially in unequal ratio to glucose), can cause the intestines to take in too much water, leading to GI discomfort. Recent research seems to show that women are generally more susceptible to fructose malabsorption than men. With increased GI distress, there are other factors to consider, such as proper hydration and mineral status. Needing to use the bathroom more frequently can cause dehydration as well as mineral depletion because of increased water loss. For further succinct and approachable information on fructose check out this resource. If you think you may be sensitive to fructose, browse this guide to understand how you can limit your exposure.
2. Eating foods that are hard to digest before a workout, such as dairy. Dairy is hard for many people to digest even when they’re in a rested, or relaxed (parasympathetic) state, which is the state we ideally need to be in to trigger the digestive process. Since most can’t digest diary well normally, it’s certainly not a good idea to consume dairy before putting your body through a stressful workout, as this puts your body into a “fight or flight” (sympathetic) state. Basically, this just means you’ll be in a stressful state that is not optimal for digestion. Dairy, and fat in general, also takes a longer time to digest than simple carbs or protein, so you want to limit these before a workout.
3. High stress from a variety of sources, such as overeating, over-training, lack of sleep, etc. can result in GI distress. As above, because we need to be in a ‘rest and digest’ or parasympathetic state for proper digestion to occur, high stress (no matter the cause) can very easily create “stress gut”, aka a gut that’s stressed out because you’re stressed out (NTA, 2019). A stress response activates the ‘fight or flight’ response which is associated with the sympathetic state. This response can disrupt the functioning of sympathetic neurons that influence various digestive functions such as the secretion of mucous to the large intestine to help remove waste, water absorption by intestinal epithelial cells, and mucosal permeability. It can also disrupt the regulation of histamine levels in the body, disrupt the intestinal bacteria in our gut, lessen the blood flow to the GI tract, and negatively impact GI motility (NTA, 2019).