Nausea From Sit-Ups

You might hate doing sit-ups, but in most cases, they shouldn't make you feel nauseated. If you feel sick to your stomach during or after a strenuous round of the exercise, it's likely not the sit-ups itself that's making you ill, but rather a related cause.

If you can figure out what's making you feel sick after an ab workout, then you can take measures to avoid it next time you're engaged in an intense core workout.

Endurance athletes in action may lose up to 3 liters of fluid in an hour, reports John Hopkins Medicine. Unless you've done 500 sit-ups in a humid environment, sit-ups by themselves are unlikely to cause this degree of fluid loss. But if you're well into a long and strenuous workout, it's important be mindful of hydration. Thirst, however, is not necessarily a good indicator of dehydration.

The optimal amount of fluids to drink depends on many factors: your size and weight, the level of intensity in your workout, heat and humidity, and diet. It's a good idea to drink extra water before, during and after heavy workouts or exposure to warm temperatures. The goal is to drink before you get thirsty. For workout sessions longer than 90 minutes, sports drinks with electrolytes are best.

Read more: Why Drink Water After Exercising?

During exercise the body produces 15 to 20 times more heat than when it is at rest. If for some reason the body isn't adequately dissipating heat, body temperature rises. High humidity, dehydration and anything else that prevents sweat from evaporating can cause your body to overheat.

John Hopkins Medicine says that can cause nausea, muscle spasms, vomiting and other symptoms. Once again, it's unlikely that sit-ups alone would cause over-heating unless they're done at the end of a long and strenuous workout, or after time spent in sauna or steam room.

Read more: If You're Throwing Up After a Workout, It May Be Time to Bring It Down a Notch

Physical activity prevents gastric emptying. That can cause gastrointestinal complaints, according to the Academy of Nutrition and Dietetics. And because sit-ups stress the very core of your digestive tract, it's possible that this could enhance any tendency toward nausea. So that alone is a good indication that you don't want to carry a heavy digestive load into your workout.

The American Council on Exercise recognizes that some people prefer to have nothing in their stomachs before working out. Performing sit-ups in a "fasted state" might take away the nausea and it might burn more fat, but you are risking quicker glycogen depletion and fatigue.

Do you find that exercise in general brings on symptoms of heartburn? You might be experiencing gastric reflux, or GERD, which can trigger nausea. This occurs when acidic stomach contents back up into the esophagus because of a weakness in the muscular band that normally seals tightly to prevent this from happening.

Gastric reflux is triggered by impact and gravity, so the rocking motion you experience during sit-ups — especially if doing them on a reclining board — could be causing reflux that triggers nausea. Cleveland Clinic recommends sitting upright while eating and for up to an hour after eating. No sit-ups.