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Struggling with GI Complaints During Physical Activity? You’re NOT Alone

It MUST be a universal experience to be in the middle of exercising, a race, or competition and suddenly your stomach starts cramping up, and feels as if it’s twisting into knots. The unexpected discomfort is abruptly all you can think about, ultimately throwing off your focus and rhythm, making it challenging to push through. Best case scenario, the cramps will fade, however, oftentimes cramps and discomfort tend to linger. It’s frustrating, even when you believe you are taking proper precautions. However, it may be comforting to know you are not alone in this tragic phenomenon.


How Common are GI Issues Amongst Athletes?

Research indicates that 30-50% of all athletes experience gastrointestinal (GI) discomfort during physical activity, with endurance athletes being particularly affected. Research estimates that 30-90% of distance runners report exercise-induced GI discomfort.


The gastrointestinal tract's response to exercise can vary depending on the activity's intensity. Individual differences are dependent on the type of activity, intensity, duration, diet, and medical conditions (such as IBS/IBD, GERD, etc.); All which can all influence the severity of symptoms.

Type of Activity: High impact activities such as most endurance and contact sports, tend to create more jostling of both the stomach and intestine which can cause unwanted symptoms (nausea, cramps, diarrhea). Whereas low-impact activity such as walking, yoga, and resistance training are less of a burden on the GI tract, resulting in lower rates of disturbances.

Intensity: With high-intensity workouts, blood flow tends to flow to muscles as a priority, resulting in reduced flow to the GI tract. As there is a reduced flow to the intestines, this may slow down gut motility and function. As a result, it’s possible that bowel movements and transit time decline, bloating, acid reflux, and abdominal pain.

Duration: The more time one spends completing physical activity, especially high-intensity physical activity, increases the odds of dehydration and electrolyte imbalances. Both of which can exacerbate already existing symptoms. During prolonged periods of activity, there’s a greater emphasis on properly hydrating and fueling to decrease the risk of distress.

Diet: Pre-fuel is arguably one of the most controllable factors when it comes to managing GI distress. Well-balanced meals containing carbohydrates, protein, fat, and color, generally take 3-4 hours to fully digest through the stomach. This is why it is important to have a well-balanced meal plenty of time in advance, with the addition of a quick digesting carb 30 minutes -1 hour before activity. Fat, fiber, and protein are difficult to digest, which can further cause irritation if the digestive process is happening during exercise.

Medical Conditions: Individuals with specific medical diagnoses may need to follow certain dietary restrictions or considerations to reduce the likelihood of flare-ups. Balancing activity with symptom management may be a learning curve, however listening to your body and progressing gradually can be beneficial.


Common Symptoms and When to Know if It's a Problem

Typical (and generally mild) symptoms include gas, nausea, bloating, and cramping. If any of the following symptoms worsen or become increasingly persistent, then further medical attention should be considered. Severe and concerning symptoms include diarrhea, bloody stools, weight loss related to GI complaints, chronic fatigue, and persistent “mild symptoms.” It’s not normal to be struggling with any symptoms greater than 1-2 weeks, especially not on a regular basis.


Common GI Triggers

●      Swallowing air or drinking from water bottles too quickly

●      Consuming highly concentrated beverages or mix-ins (Not following proper mixing instructions)

●      Energy drinks

●      Poor posture during activity

●      Eating high-fat, fiber, protein, or fructose-rich foods before training

●      Dehydration

●      Use of NSAIDs (non-steroidal anti-inflammatory drugs) like ibuprofen


This may sound intimidating, as if some factors are somewhat uncontrollable. On the bright side, there are further proven precautions one may take to prevent and/or improve symptoms. It’s important to note that everyone digests and tolerates foods differently, where you could eat a banana before every run and feel amazing. However, I know bananas don’t sit well on my stomach and I completely avoid them. It’s truly a long game of seeing what works for you and your body.


How to Avoid/Limit GI Issues During Exercise

Avoid slow digesting foods prior to exercise

○      Protein (eggs, chicken, yogurt, meats, shakes, bars)

○      Fat (greasy/fast food, nuts, peanut butter)

○      Fiber (beans, oats, avocado, popcorn, chia seeds)

Incorporate multiple transportable carbohydrates prior and during activity

○      Easily consumed and utilized to provide quick energy, which have glucose, fructose, and/or galactose

○      EX - sports drinks, gels/gus, chews/gummies, energy bars, fruit

○      Avoid foods with high amounts of fructose if you have a sensitive stomach (fruit juice, honey)

Consider slow nutrition trials - AKA change one thing at a time

○      Pick one potential “trigger” to modify with the goal of pinpointing where things go wrong

○      Trial the change for at least a couple of days until it’s ruled out

○      Creating a list of foods which trigger you!

Avoid NSAIDS prior to activity

○      Ex - Ibuprofen, Aspirin

Stay hydrated throughout the day

○      At least 8-10 cups per day

○      Urine should be clear - pale yellow, odorless, and plentiful

Intra-exercise hydration

○      6-12 oz water every 20-30 minutes of exercise (for the first 60 minutes)

○      During/following exercise lasting 60-90 minutes or more, incorporate a carb and electrolyte containing sports drink (Gatorade, Liquid IV, Drip Drop, etc.)

○      High-intensity, sweaty workouts call for a higher demand in electrolytes, whereas shorter and less intense workouts require only water for hydration

○      30-60 grams of carbohydrates per hour after the first 60 minutes of activity are recommended to sustain energy

○      Rehydrate with 16-24 oz of water for every pound lost during activity

Navigating GI distress during physical activity can be challenging, but it's important to remember that you are not alone. Many athletes experience discomfort and understanding the various factors that contribute to GI distress can help manage and minimize symptoms. By considering the potential factors, you can tailor your approach to better suit your body’s personal needs. Finding the right balance may take time and experimentation, but with persistence and careful monitoring, you can definitely make progress. Be proactive in managing your symptoms, try new strategies, and you can continue to enjoy and excel in activity.


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