According to diabetes experts, muscles are responsible for about 90 percent of the body’s use of glucose as fuel. Exercise also affects various hormones which have a direct impact on blood sugar levels. It’s not surprising, then, that non-diabetic hypoglycemia, or low blood sugar, is common in frequent exercisers and athletes.
If you’ve ever worked out on an empty stomach, you’ve probably experienced the dizziness, muscle weakness and exhaustion of a blood-sugar crash. Understanding how your blood-sugar levels are controlled, and what you can do to prevent these crashes, can help you avoid these symptoms.
How Blood Sugar Works
The sugar called glucose, which is stored in the muscles and liver, is the primary fuel your muscles use during strenuous activities. As part of a careful balancing act, two hormones are released to try to maintain healthy levels of glucose in the blood, where it can be used readily.
Insulin is released into the blood by the pancreas when blood sugar levels are too high, where it bonds with specialized receptors on the cells. Insulin stimulates the cells at these receptors and tells them to absorb glucose. Once these cells respond to insulin, blood sugar levels drop.
When blood sugar is too low, however, the pancreas releases glucagon instead. This hormone tells the liver to releases some of its stored glucose into the blood so that can be used as fuel.
Exercise puts much higher demands on your muscles, forcing them to utilize more fuel — in much the same way as making your car go faster, or pull a heavy load, will increase how much gas it burns. Overtraining can even cause a permanent shift in this balance by increasing insulin sensitivity, which will make it much more difficult for you to maintain a healthy blood sugar balance.
Keeping Your Balance
Research suggests that endurance training, as opposed to strength training, can be beneficial in preventing exercise-induced hypoglycemia. While strength training uses carbohydrates like glucose for fuel, endurance training uses fat as the primary source of energy. This will prevent blood sugar levels from getting too low.
The most effective method for preventing exercise-induced hypoglycemia, though, is by adjusting the timing and composition of your meals. Focus on complex carbohydrates such as whole grains, starchy vegetables and legumes, which will give you several types of sugar and dissolve more slowly in your system. Try to have a large, carbohydrate-heavy meal at least three hours before your workout so that you have plenty of stored glucose when you start your exercise.
Throughout the day, eat six small meals and snacks rather than the traditional three large daily meals. These meals and snacks should also be made mostly of complex carbohydrates and proteins. Avoid simple sugars like sodas and baked goods, since these will cause a spike in insulin — a response to the quick release of sugar — which will, in turn, cause your blood sugar to crash.
Drinks like coffee that contain large amounts of caffeine can also cause a crash when the stimulant effects of the drink wear off. The symptoms of this “caffeine crash” can be very similar to hypoglycemia.
Most importantly, discuss your hypoglycemia with your doctor, since it can sometimes be a symptom of a more serious condition, such as diabetes.
Have you ever experienced exercise-induced hypoglycemia? How have you managed it? Please share your tips in the comments!