Why do I feel so awful when my blood glucose is high? When the blood glucose is high, many people feel unwell. Here are the most common symptoms, and the reasons for them:
TIRED. Your cells need glucose for energy, and the glucose is not getting to them. In fact, your cells are starving and cannot work efficiently. This makes you tired.
INCREASED URINATION. All blood is filtered by the kidney. If there is excess glucose in the blood, this also goes to the kidneys. The kidneys can RE-ABSORB and recycle normal amounts of glucose, as the body does not want to lose it in the urine. However, when the glucose is too high, it can exceed the kidneys' ability to re-absorb it. The excess glucose then goes out in the urine, literally dragging water with it. This means that more urine is produced, and you have to urinate more often.
THIRST. The increased urination caused by blood glucose dehydrates you. Your body perceives the need for extra fluid, making you feel thirsty. Excess glucose in the saliva may also contribute.
WEIGHT LOSS. This directly results from the loss of glucose in the urine. Keep in mind, glucose is a sugar, and represents calories to the body. Losing glucose in the urine means losing calories in the urine. This is like eating a piece of bread and having some of the calories from it lost in the urine. You are not using all the calories in your diet and - as you effectively starve - weight is lost. Furthermore, uncontrolled (high) glucose boosts the metabolic rate, making it easier to lose weight. This might sound like a good thing, and it might be, if the weight lost was only lost as fat. Unfortunately, muscle is lost as well, and you can feel quite unwell and weak as this goes on.
CHANGE IN VISION. This is directly due to a physical change in the shape of the lens of the eye. When the glucose in the blood goes up, extra glucose gets into the lens of the eye. When this happens, water again follows it (very similar to the water following the glucose as it passes through the kidney). When extra water enters the lens, it alters the shape of it. The lens loses its ability to focus light for the eye, which you perceive as blurred vision. This is often a most annoying symptom to the newly diagnosed diabetic person, and it must be emphasized that any visual change that occurs with high blood sugars is TEMPORARY, i.e., it corrects with correction of the glucose. However, this takes time, and it may be as long as 6-8 weeks after glucose has been corrected that vision returns to its baseline, and stays there. Prescription eyeglasses should not be prescribed when the glucose level is high, or changing.
MOODINESS. The brain does not like an environment of high glucoses, and moodiness is a very common symptom of high sugars. DECREASED ABILITY TO CONCENTRATE is also common for the same reason.
MUSCLE CRAMPS. As discussed under weight loss, muscle mass is lost when glucoses are uncontrolled. There is some tissue breakdown, and there is considerable loss of "electrolytes". These are salts that are present in all tissues of the body, and are abundant in muscle. When they are lost, the muscle becomes very prone to a cramping pain.
NUMBNESS OR TINGLING OF THE HANDS OR FEET. As the glucose goes up, more of it passes into the nerve tissue. This radically alters the electrolytes (salts, see above) in the nerves, as well as changing many other functions, and even structures of molecules (protein and enzyme) in the nerve. When the nerve is so affected, it gives false messages to the brain, and this is perceived as numbness, tingling, or even pain.
YEAST INFECTION. Yeast live well in the environment of the vagina. If the blood glucose is high, more glucose is available in the vagina as well, and the yeast organisms like it even more. One or two yeast organisms will multiply, causing a significant, uncomfortable infection. This initiates a vicious circle where high glucose makes the yeast grow better, and the yeast infection (like any other infection) makes the glucose higher, which worsens the infection, and so on. Generally, one must treat both the high glucose and the infection before both will improve. Yeast infections can also occur under the foreskin of the penis, by a similar mechanism.
The most common symptom of high blood sugars is to have no symptoms at all! This is why there are so many people walking around with diabetes without knowing it - they have no symptoms.