Dizziness During Exercise

Feeling dizzy or lightheaded during exercise can result from a temporary or relatively simple problem, or it might signify a serious medical issue. If you begin to feel dizzy, stop immediately. Sit down, rest, and lower your head to see whether putting it down helps blood move back to your brain. Solving the problem, however, depends on its cause.

Dehydration

• Dizziness is very common if a person has been exercising hard and sweating, especially in high heat or humidity. It's important to keep hydrated, because otherwise during exercise your heart will have to work harder to pump the blood, increasing the pulse rate and causing blood vessels to constrict to keep blood pressure up. When you're dehydrated, the brain receives less blood and you feel dizzy. The body wants you to faint to help increase the blood reaching your brain. So sit down immediately, cool yourself down, and drink fluids to help avoid heat exhaustion or heatstroke. Exercising at high altitudes can make the problem worse. Note that diuretics can also cause dehydration, so if you're taking them, ensure you get plenty of water before exercise.

Low Blood Sugar

• If you don't eat before exercise, that can mean low blood sugar when you start. Working out on a full stomach is not smart, but eating a snack or a light meal can help prevent low blood sugar. If you will be exercising intensely and for long periods of time, as in several sets of tennis or a long jog, take a banana or a granola bar to eat during breaks.

Heart Problems

• Dizziness can sometimes signal a heart problem related to inability to move blood efficiently through the body or an abnormal rhythm. Dizziness can be a sign of a potential heart attack or an irregular heart rate, either too fast or too slow.

  In addition, some medications, especially those designed to help existing heart problems, blood pressure or heart rate issues, can produce dizziness. These include certain beta blockers, nitroglycerin, metoprolol, and others designed to change the way the blood vessels function. And many drugs, such as anti-depressants and tranquilizers, might cause dizziness with or without exercise. Read the information sheets on your medications and consult your doctor if you think you might be taking one that affects your heart or blood vessels. If you become dizzy during exercise and the feeling can't be attributed to simple dehydration, consult your physician to ensure you don't have a more serious problem.