Combating Exercise-Induced Nausea

Written by: Pip Taylor

Professional triathlete and sports nutritionist Pip Taylor explains how to overcome the nauseous feeling that many of us experience in longer-distance races.

Q: I am a marathon runner and have been running one to three races each year since 2000. As early as 16 miles and perhaps as late as 22 miles into the race, I experience nausea. There have been some races in which I have not experienced this problem, but these seem to be the exceptions. The common denominator between those races during which I did not experience a problem was cool weather. Unfortunately, at my race in April 2008, I was so nauseous at mile 22 that I walked the remainder of the race. The November 2008 race—the New York Marathon—was my worst experience. It is probably important to note we had to wait four hours in the cold before the race start, and despite all my clothes, I was shivering by race time.

I never experience a problem with nausea when I do my long training runs. I have tried various things to try to combat my problem. I have tried different gels; I have used powdered drink mixes instead of gels; I carry my own water so that I can sip it or drink whenever I want instead of waiting for water stops; I have eaten bits of crystallized ginger. I am preparing to run another race on May 3, and I was wondering if you have any words of wisdom or strategies I could try.

Suzanne Squires

TK

Taylor: It seems like you are doing the right things by experimenting with different gels, being aware of your fluid intake and training well for your races. Because nutrition is very individual and depends on several variables, there will always be trial and error. However, if you continue to have issues, I suggest visiting a sports nutritionist who can assess you in person. In the interim, here is a basic checklist of possible causes of nausea, along with some suggestions:

Fluids and electrolytes: not enough or too much. Dehydration is a major cause of all GI disorders and discomfort, and be aware that this can happen just as readily in cold weather as it can in hot and humid weather. Conversely, drinking too much water can lead to a state of hyponatremia (low blood sodium levels), which also has nausea as a key symptom. Individual sweat rates and sweat concentrations, combined with varying environmental conditions and fitness levels, mean that nutrition plans must be personalized. You mention the cold weather as a factor, and in fact, some individuals are more prone to cold dehydration because it is not obvious that you are losing salts and fluid, so they are not as conscientious in replacing them. Iced drinks may also not be appealing when it is very cold, so it is important to develop a nutrition plan that encompasses fluid intakes as well as salt and energy needs and try to stick to it rather than relying on thirst/hunger mechanisms, which are pretty unreliable, especially when straining hard in competition and training. Try weighing in pre- and post-training sessions to get a bit of an idea of your sweat rates, which will help you determine fluids needed.

Blood sugar levels that are too high or too low. Low blood sugar levels are associated with dizziness and nausea. However, too much of a good thing can also be your undoing: Eating too much, either in volume or concentration, or consuming highly concentrated drinks can also lead to similar feelings of sickness as the stomach struggles to cope.

Eating too close to the race start. Give yourself two to four hours between your pre-race meal and the start time. Even if you feel like you can tolerate eating close to training, race day presents a whole different scenario, and the presence of nerves or anxiety can reduce tolerance of foods. You can even try liquid foods if that would be helpful.

Chemical and hormonal influences, including anxiety and exercise stress. Stress hormones are often linked to feelings of nausea and may also hamper nutritional plans. Both hot and cold weather can also further stress the body. Your energy needs may be increased in very cold weather as your body tries to conserve heat, so try to stay warm as long as you can., even if that means planning on taking old throwaway clothes to the start line and ripping them off at the last moment. It is interesting to note that you feel as though your symptoms only occur when racing and never during training.

Excessive protein, fiber and/or fats in pre-race meals. Meals in the days leading up to the race need to be easy to digest. Stick to carbohydrate-based meals with lean proteins and small amounts of fat. Low-fiber/low-residue meals and snacks may be more comfortable and lessen symptoms or episodes of GI disturbance for some.

Other possible irritants: Alcohol, caffeine, spices, artificial sweeteners, ibuprofen, and even dairy foods and fructose cause upsets in some people. The body’s systems become more sensitive to any irritants when under physical, emotional or mental stress. Racing can present all three, so try to determine anything that might affect you beforehand. (Try keeping a food log to reveal anything you may not have considered before.) You may also want to check with your doctor about any possible underlying allergies or intolerances that are exacerbated by exercise.

What else can you do?
– Talk to your physician about any anti-nausea medication that may offer some relief and is also appropriate and safe to use when exercising hard.
– Probiotics may assist with GI disturbances (although they are more likely to alleviate disturbances of the lower tract) as well as being of assistance to general immune health.