It Is Ok to Become Lightheaded or Nauseas During a Workout?

The only time i have been light headed or nauseas during or after a workout is when i havnt had enough food for the day. Last week i was so under my calorie intake that i was breathing hard during a lighter workout then usual.

Thats not a good thing. Check your heart rate and make sure you are not pushing too hard. I know when I run or spar my way to a 85-90% work heart rate I get the same way.

Just some info I found


Hydration

Lack of and too much hydration may increase the chances of feeling nauseous during or after exercise. The body produces sweat during exercise to help cool its core temperature. Electrolytes such as sodium and potassium are excreted, along with fluids. Depleted levels of fluids and electrolytes during exercise can lead to nausea. The "European Journal of Applied Physiology" published a study in December 2000 that found dehydration delayed stomach and intestine emptying. Delayed gastric emptying induced symptoms of nausea. Overhydration also can cause stomach sickness. Drinking too much water fills the stomach, leading to a bloated feeling.
Hypoglycemia

Hypoglycemia, or low blood sugar, can lead to symptoms of nausea, dizziness, headache and loss of function. Sugar is used by the body to power muscles during exercise. Exercising intensely or for prolonged periods of time can use up the body's glucose reserves, leading to hypoglycemia. Shaking, blurred vision, fatigue and unclear thinking during activity may indicate this condition. Consuming simple carbohydrates and protein can quickly regulate blood sugar, often alleviating symptoms. For those with diabetes, discuss your health with a doctor before exercising.
Overexertion

Pushing the body beyond its endurance also can induce nausea, according to the National Safety Council. Overexertion can occur while lifting heavy objects, performing aerobic exercises or walking on stairs, if the body is not accustomed to the activity, particularly after an illness or surgery. Come back slowly after a long layoff from vigorous exercise, working out at low intensity for short periods. When strength and endurance return, higher levels of exercise can be sustained without fatigue and nausea.

Read more: http://www.livestrong.com/article/538431-the-causes-of-feeling-nauseous-weak-after-exercise/#ixzz22JntLKdP

I would listen to your body and maybe back off a little when that happens. I started boot camp like 6 weeks after giving birth and would feel that way at first. Looking back, I think I should have started off with less intensity and worked my way up to boot camp, but it ended up being okay. What I would do that seemed to work for me was to eat 1/2 of a protein bar before the workout; if I ate a whole one it made things worse. If I still started feeling light headed or nauseous during the workout, I would back off the activity a little and do a modified version until I felt better. Also, be sure to take water when you need it, but take small drinks rather than chugging it. Like others have suggested though; if it persists or gets worse, I'd consult a doctor.