Fitness Q&A by Richard Weil

What causes abdominal cramps during exercise? What can I do to prevent them?

Answer:

If you mean prevent muscular cramps that occur in the abdominal muscles while doing exercises like crunches and situps, the answer is not always clear since the cause of skeletal muscle cramping is not definitively known. You can experiment with making efforts to stay hydrated, for example, by supplementing your diet with bananas (for the potassium) and refueling with ergogenic drinks to replace electrolytes. These techniques don't always prevent cramping, but they are worth trying. When the cramps do occur, you should lay flat on your back, or stand up straight, and reach your arms over your head until the cramp resolves. Reaching overhead stretches the abdominal muscles and releases the cramp. If cramping continues, then it should be reported to your doctor.

If you mean internal cramping like a bellyache, this can be due to food or drinks you consume prior to exercise. Dairy, high-fiber foods, and sweetened beverages are just some of the most likely culprits, although there can be other reasons as well. A 1992 analysis during a Half Ironman competition revealed some interesting facts related to GI complaints. All of the triathletes who had eaten within 30 minutes of the start of the event vomited while swimming. If the pre-race meal (eaten anytime) had a higher fat or protein content, vomiting was more common. Hypertonic beverages (beverages that contain a higher concentration of solutes like electrolytes or sugar than that found in body cells) like Gatorade also caused more severe GI symptoms during the race, and all of the triathletes who experienced intestinal cramps had eaten fiber-rich foods in the pre-race meal. Excessively sweetened beverages can slow down the flow of fluid through the stomach, and this can cause discomfort. Ergogenic beverages that have 7% glucose tend to be tolerated well unless athletes consume excessive amounts.

In another trial, researchers studied carbohydrate loading in the days prior to exercise. One group of athletes ate the traditional pasta and rice diet, while another group ate less carbohydrate and substituted instead with a maltodextrin drink. Both groups had similar treadmill times until exhaustion, and muscle glycogen concentrations as determined by muscle biopsy, but the supplement group had fewer GI complaints.

Here are some tips for avoiding abdominal cramps that you can follow prior to working out:

    1. Avoid caffeine.
    2. Limit consumption of dairy products.
    3. Limit consumption of high-fiber foods.
    4. Avoid any other foods that you know upset your stomach or give you gas.
    5. Stay hydrated. Dehydration can slow digestion of food and cause stomach problems. Drinking 7-10 ounces of fluid every 20 minutes is recommended.
    6. Beverage temperature should be between 50 and 59 degrees.
    7. Avoid taking aspirin, ibuprofen, products with sorbitol, fructose, or large doses of vitamin C prior to your workout. All of these can cause diarrhea or otherwise upset your stomach.
    8. Avoid excessive amounts of sweetened beverages. Excessive sugar will slow down absorption of fluid through the gut during exercise and cause discomfort.

I hope that helps.

Thank you for your question.


Last Editorial Review: 11/22/2006