Blood sugar is the amount of glucose present in the blood. Glucose is the primary source of energy used within the cells. It's broken down from carbohydrates in the digestive system and transported to the cells via the bloodstream. Glucose is a tightly regulated commodity; it should not get too high or too low. Since glucose is such an important part of the body's metabolism, it is also greatly affected by exercise.
Definition
Reactive hypoglycemia refers to a state of low blood sugar that occurs within three hours after a meal. It is associated with feelings of hunger, weakness, shakiness, fatigue, headaches, lightheadedness, anxiety and confusion. You will generally want to keep your blood sugar above a measurement of 100 mg/dl --- in other words, 100 milligrams of glucose per every deciliter of blood. A pre-exercise range between 100 and 250 mg/dl is normal, but anything above 250 mg/dl demands caution. If it climbs to at least 300 mg/dl, then your blood sugar may be too high to exercise safely. You can measure your blood sugar at home or at the doctor's office. Symptoms will diminish once your blood sugar levels return to normal.
Exercise
Exercise is considered to be a natural regulator of blood sugar and a benefit to those with metabolic disorders. With a sustained amount of exercise, your muscles absorb glucose and remove it from the blood at a much faster rate. This process is normal. If you are already prone to low blood sugar, however, then exercise may only exacerbate the problem. It may not be safe to exercise once your blood sugar falls below 100 mg/dl. This is a particular problem for diabetics, who have difficulty regulating blood sugar naturally.
Solution
Hypoglycemia resulting from exercise after a meal is likely to be mild in nature and only rarely produces serious symptoms. The solution is to eat some kind of high-carbohydrate snack, such as crackers, fruits or bread, during or after the exercise. Even a glass of orange juice will suffice. The snack should correct low blood sugar within several minutes. If a serious underlying health problem is to blame for reactive hypoglycemia, then you may instead need to seek some kind of medical treatment.
Considerations
If you eat a small snack to raise your glucose levels, then you will generally want to avoid foods with too much sugar. It might seem to make sense at first that you can restore blood glucose by consuming sugary foods, but the sugar digests so quickly that blood glucose levels will once again fall below normal levels. You should choose foods that are both high in carbohydrates and yet digest at a more moderate pace.
