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Tips For Runners To Avoid Common Stomach Problems

Stomach problems are a fairly common health issue for runners because running can be highly disruptive to the gut and digestive system.

The pushing motion of running, and the impact on each step, agitate and stimulate the gut, often triggering contractions of the smooth muscle lining the GI tract. This can affect our stomach issue.

When we run, especially long-distance, or engage in other forms of intense exercise, blood is diverted away from the digestive tract to meet the increased demand from the heart, oxygenation, lungs, and working muscles.

This causes digestive system to slow down or nearly stop, leaving any remaining food to hang around in our stomach. If we go running after eating, undigested food in our stomach might splash around, and the processing of it may stop.

As food sits in the stomach and digestive tract, the bacteria in our gut ferment the sugars and produce gas, contributing to gas build up and abdominal discomfort.

We can experience gas, bloating, indigestion, abdominal cramps, side stiches when running, and stomach pain after running.

Types Of Stomach Issues Common For Runners

Stomach pain after running or an upset stomach after running is often caused by one of the following symptoms or common stomach problems for runners:

  • Stomach cramps or abdominal cramping

  • Side stitches

  • Runner’s diarrhea

  • Heartburn

  • Nausea

  • Bloating

  • Indigestion

  • Gas

  • Burping

Most Common Causes of Stomach Pain After Running

1. Running Too Fast

The faster we run, the less blood our digestive system receives, because it is pushed more aggressively towards our skeletal muscles. Therefore, any pre-workout meals or snacks may upset our stomach during a hard workout or a fast run.

2. Running Too Soon After Eating

One of the most common causes of stomach pain after running is running too soon after eating or eating too much before our workout. This can cause anything from bloating, side stitches and nausea.

3. Poor Fitness

If we are not too fit or returning to running after an injury, we may be more prone to side stitches. Weak abdominal muscles, heavy breathing, rapid breathing, and poor running form can contribute to side stitches.

4. Drinking Carbonated Beverages

Running after drinking carbonated beverages like seltzer, soda, and beer can trigger stomach pain after running because the bubbles contribute to bloating.

5. Drinking Too Much Water

As runners, we know that drinking water and staying well hydrated is important for health and athletic performance, but drinking too much water can cause a stomach ache after running.

Drinking plain water causes people to feel more bloated compared to drinking electrolytes– or carbohydrate-infused beverages. Plain water can also be absorbed more slowly than sports drinks with electrolytes, so we can feel a splashing sensation and experience an upset stomach after running if we drink too much plain water.

Drinking too much plain water, and lacking of electrolytes, while running disrupts the fluid balance in our body. This can lead to a dangerous condition known as hyponatremia.

Hyponatremia results when the sodium content in our cells is diluted too much by an excessive intake of water. Cells retain water and swell, causing water retention and bloating, and if severe, even coma and collapsing.

6. Dehydration

Dehydration can also lead to stomach problems while running or stomach pain after running.

Dehydration can slow the gastric emptying rate, leaving undigested food to sit around in our stomach if we go running too soon after eating.

Also, if we’re dehydrated, our stomach tries to compensate for the lack of fluid in the body by retaining water. Because we sweat when we exercise, dehydration is increased after a run, which can lead to stomach bloating or indigestion after working out.

7. Fatty Food

Running after eating a fatty meal is a recipe for stomach problems. A fatty meal sits around longer in the stomach and takes longer to be digested, which can lead to stomach cramps when running or an upset stomach after running.

While eating vegetables and legumes is very healthy and should be recommended for all runners, fiber foods and running combination is not a good recommendation.

8. Too Much Fiber

Fiber acts on the digestive system in many ways. For example, it slows the rate of gastric emptying, which is good in some ways because it can make us feel fuller for longer, but it can cause bloating and cramping while we are running.

Fiber also bulks up the volume of food and eventual stool in our digestive tract, stimulating inflammation and contributing to a feeling of heaviness, distention, or bloating of our abdomen.

Running after eating a meal or snack high in fiber can cause indigestion, bloating, gas, diarrhea, and digestive distress while we are running.

9. Running In the Heat

Stomach problems while running are especially common if it’s hot, humid, or when we are running or working out.

When the body temperature rises, blood vessels increase in an attempt to cool our body down. The heat can also lower and block our fluid balance and increase our exertion level and respiration rate, all of which can cause various stomach issues while running, such as cramps, side stitches, bloating, and nausea.

10. Poor Breathing Patterns

Holding our breath, gulping too much air, or rapid and shallow breathing can cause side stitches when we run.

How To Prevent Stomach Problems When We Run

1. Test Your Fueling Strategy

We should focus on waiting long enough to go running after eating. We should wait about 3-4 hours to run after eating a large meal, 2-3 hours for a small meal, and 1-2 hours after most snacks unless it’s a very small snack easy to digest, and consisting of only simple carbohydrates.

Limit fatty foods, fiber foods, artificial sweeteners, high-carbonated beverages.

2. Rethink Hydration

If we are well-hydrated, our urine should be pale yellow. If we are feeling bloated, consider sports drinks with electrolytes.

The general recommendation is to drink 120-180ml of fluid every 15 to 20 minutes during our run, depending on the environmental conditions, our sweat rate, the intensity and duration of the run, and our pre-run hydration status.

For longer runs (60 minutes or more), we should alternate between water and sports drinks with electrolytes. Especially if we are consuming energy gels, we should drink plain water, to avoid adding too much electrolytes in one shot.

3. Slow Your Pace

Slowing down will reroute more blood to our stomach and digestive tract. It also eases respiration and can prevent stitches. Especially when running Ultra distance runs, we should not push too hard of we feel some symptoms in our body.

4. Fix Your Running Form

Running with a bad running form leaning forward too much and hunched over can compress our diaphragm and lungs, and can cause side stitches while running. We need to make sure we run in a good running form and running tall.

5. Strengthen Your Core

A strong core can support good running form and prevent side stitches.

6. Breathe Evenly

Slow, even breathing while running can prevent side stitches and ensure we don’t swallow too much air, which can lead to bloating, burping, and gas.

7. Avoid the Hottest Part Of the Day

During hot, humid weather, we should try to run in the morning hours or evening hours, or consider taking our workout to a treadmill indoor.

8. Try Ginger Chews

Ginger can ease nausea and indigestion. We should try some nice ginger chews, or ginger powder or fresh ginger.

Avoid Stomach Issues While Running, Focus On Good Nutrition And Meal Schedule According To Training Schedule, Enjoy Some Great Runs!


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