Why You Might Feel Nauseous at the End of a Run

Man resting with hands on knees during a run
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Nausea during or after a run can happen for a few different reasons. If you ate less than an hour before your run, that's too close to your workout and it's possible that you'll feel nauseous and even throw up whatever you ate. It's OK to eat a light snack about 90 minutes before your run. Try to eat something that is easily digestible, such as some toast with peanut butter or a banana. If you eat something that takes longer to digest, like fatty or fried foods, you should give yourself at least two hours before running.

Dehydration Is a Possibility

You might also feel nauseous during or after a run because you're dehydrated. Nausea is an early symptom of dehydration. The current recommendations for hydrating while running is to obey your thirst and drink when your mouth is dry and you're feeling thirsty. In general, that means about 6 to 8 ounces of fluid for runners running faster than 8-minute/mile pace, and 4 to 6 ounces of fluid every 20 minutes for those running slower than that.

During longer workouts (90 minutes or more), some of your fluid intake should include a sports drink (like Gatorade) to replace lost sodium and other minerals (electrolytes). And don't forget to rehydrate with water or a sports drink after your run. If your urine is dark yellow after your run, you're dehydrated and need to keep rehydrating. It should be a light lemonade color.

Some runners don't drink during their runs because they don't have access to water if they're running outdoors. An easy solution to that problem is to run with a hand-held water bottle or belt carrier made specifically for runners. If you really don't like to carry water with you, plan your route so that you have access to water fountains or a strategically-placed water bottle.

Use caution when the conditions are extremely hot and humid. Even if you attempt to stay hydrated when running in those conditions, you could still be at risk for dehydration and other heat-related illnesses. Run indoors or reduce the distance or intensity of your workout. Get more tips on how to stay safe when running in the heat.

Is It Your Sports Drink or Energy Gel?

If you've felt nauseous during a long run and you've consumed a sports drink or energy gels while running, you could be reacting to the drink or gels. Some runners find that their stomachs are sensitive to sugary-sweet sports drinks or energy gels. If you think your sports drinks may be the culprit, try making your own. Just add four tablespoons of lemon juice, a couple pinches of salt, two tablespoons of honey to 16 ounces of water and you have your own homemade sports drink, complete with carbs and electrolytes. Some runners find that homemade drinks such as this are much easier on their stomach than Gatorade or other commercial sports drinks.

If energy gels seem to be bothering your stomach, try sticking to more natural food options for energy during long runs. Some runners fuel with dried fruit, nuts, or honey (which are available in Honey Stinger packets).

You May Have Run Too Hard

Another possible cause of nausea during or after running is that you simply ran too hard and overexerted yourself. One way to avoid this problem is to make sure you're warmed-up before starting an intense run and to run at a pace that you're ready for.

What to Do if You Feel Nauseous After a Run

If you feel like you might throw up after a run, sip some water very slowly, in case you are dehydrated. If heat is a likely culprit, make sure you get in air conditioning as soon as possible to cool off. Whatever the suspected cause may be, don't force yourself to continue running or do another activity if you're feeling nauseous. Just take it easy and, if you're still feeling sick or throwing up after several hours, you may want to consult a healthcare professional.

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Article Sources
  • Maharam, Lewis, MD, et al. "IMMDA's Revised Fluid Recommendations for Runners and Walkers" 5/6/2006