Fainting or watching someone faint can be a scary situation. Fainting, especially during exercise, is your body telling you there is something wrong. Two common causes of fainting during exercise are low blood glucose or low blood pressure. There are special precautions you can take to avoid a poor exercise response.
Hypoglycemia
Hypoglycemia, also known as abnormally low blood sugar, can result in fainting, particularly during exercise. During periods of physical activity, your body relies on blood glucose to help supply the means for energy production. If you start with a low blood sugar, you may deplete your supplies during exercise and experience fainting.
Hypoglycemia Prevention and Treatment
The best way to deal with hypoglycemia is to stop it before it starts. If you are diabetic, test your blood glucose before you exercise. The American College of Sports Medicine recommends not exercising if your blood glucose is equal to or less than 70 mg/dL. Other signs that your blood glucose might be too low for exercise are symptoms such as lightheadedness, hunger, anxiety, weakness, fatigue, confusion, sweat and shakiness. If you think your blood glucose is too low, try having a small snack such as 4 oz. of fruit juice, a teaspoon of sugar or honey or 8 oz. of milk. Wait 15 minutes and re-test your glucose. If you are not diabetic, have a small snack and wait for your symptoms to subside. To prevent hypoglycemia after exercise, replenish your lost energy stores with a drink that combines carbohydrates and protein, such as milk.
Hypotension
Fainting during exercise could also be a sign of low blood pressure. When your blood pressure falls too low, your brain does not get enough blood, which may result in fainting. During exercise, it is not unlikely that dehydration can lead to low blood pressure and cause you to faint. A low blood pressure is considered a systolic reading of 90 mmHg or a diastolic reading less than 60 mmHg.
Hypotension Prevention and Treatment
Take precautions to prevent fainting from too low of a blood pressure, take some precautions. Buy a home monitor blood pressure and take your blood pressure before your workout. Another way to prevent hypotension from dehydration is to stay hydrated. Drink an adequate amount of water, about eight glasses per day. Also, during exercise, drink water to replace fluids you lose while sweating. Most importantly, listen to your body, if you feel thirsty, drink water.
References
- National Diabetes Information Clearinghouse: Hypoglycemia; October 2008
- "ACSM's Guidelines for Exercise Testing and Prescription"; American College of Sports Medicine; 2006
- Diabetes In Control.com; Preventing Hypoglycemia During and After Exercise; Sheri Colberg, Ph.D., FACSM; November 2008
- MayoClinic.com; Low Blood Pressure; Mayo Clinic Staff
- MayoClinic.com; Water: How Much Should You Drink Everyday?; Mayo Clinic Staff
