Many people falsely think that nausea during exercise occurs only to those who are out of shape. Although nausea may be common in cases of less physically fit people, it can also occur to trained athletes in conditions where the athlete is dehydrated, had too much or too little food prior to the workout or is suffering from anxiety or a more serious medical condition.

Dehydration

Dehydration commonly causes nausea, according to the Nausea Help website. The U.S. Department of Agriculture stresses that athletes must continue hydrating themselves before, during and after exercise. In addition, Nausea Help suggests drinking at least 2 cups of water within a half hour before a workout. A half cup of water should be drank at least every 15 minutes during a workout. This will help you stay hydrated and avoid feeling nauseated.

Low Blood Sugar

Breakfast is often called the most important meal of the day because it provides you with energy for the rest of your activities. According to Military.com, not eating breakfast and working out can lead to dizziness and nausea because, at that point, you will have been without food for 10 to 12 hours after sleeping, resulting in low blood sugar. Similar results could occur if you skip lunch or dinner and exercise in the afternoon or evening.

Overeating Before Working Out

As much as eating before a workout is important, it is also essential not to eat too much before exercising. If you eat a meal, wait at least an hour to work out. Having a big meal close to a workout can result in nausea and vomiting. Avoid consuming large meals before an intense workout and allow yourself time to digest each meal.

Anxiety

Nervousness or anxiety before a big event can contribute to nausea while exercising. According to the "Ultra Cycling" magazine, because you do not usually work out under an immense amount of stress, your body may react to anxiety with nausea. Eat right, stay hydrated and use meditation and proper breathing when dealing with anxiety prior to an important event or workout.

Other Reasons

There are also many other medical reasons that can cause nausea during your workout that are unrelated to exercise. Depending on your other symptoms, nausea can be an indication of variety of serious conditions. According to Familydoctor.org, nausea may occur because of overheating, food poisoning, stomach flu, gallstones, heartburn, serious head injury, ketoacidosis and many more. Talk with your doctor for a proper diagnosis if your nausea does not subside.