When your blood glucose is high, your body is neither storing nor utilizing glucose properly. You’re not burning energy efficiently, nor are your cells getting the fuel they need when they need it. The overall effect is a lowering of physical energy on the cellular level. If you are also suffering from a lack of proper sleep due to excessive urination during the night, you will feel even more tired.
In fact, nearly all the signs and symptoms of high blood glucose can contribute to making you feel fatigued, even exhausted. Exhausted people often resort to eating high-carbohydrate snacks for a boost of quick energy, and this, of course, raises the blood glucose level more, making the problem worse rather than better.
Chronic constipation or chronic diarrhea
Both constipation and diarrhea can be caused by high blood glucose, acting on different sections of the bowel. When high blood glucose affects the small intestine, the result is often diarrhea; when it affects the large intestine, the result is often constipation.
The two intestines have very different jobs, which helps to explain how high blood glucose can affect them differently. The job of the small intestine is to absorb nutrients from digested food, and the job of the large intestine is to absorb water from indigestible waste material.
When neuropathy from elevated blood glucose affects the enteric nerves — the gut’s command and control system — in the small intestine, the result can be dysfunctions in motility, leading to delayed emptying into the large intestine. This causes the stagnation of fluids in the small intestine, allowing bacterial overgrowth that causes bloating, abdominal pain, and diarrhea. Frequent diarrhea is seen in 22% of persons with diabetes. Enteric neuropathy, in addition to laying the ground work for bacterial overgrowth, can in itself be a painful chronic condition similar to the foot pain suffered by people with peripheral neuropathy.
In a similar way, nerve damage can slow the movement of waste through the large intestine. Slow-moving waste is essentially dehydrated — or dried out too much — by the large intestine, resulting in constipation.
Constipation can also be caused or made worse by the dehydrating effects of excessive urination and by some medicines, especially narcotic pain killers, some antidepressants, and the calcium channel blocker class of high blood pressure medicines.
Erectile dysfunction, or difficulty maintaining an erection, is a common side effect of high blood glucose, and roughly half of men with diabetes over the age of 50 experience it.
A healthy erection requires healthy nerves, healthy blood flow, the right balance of hormones, and sexual stimulation. The mechanics of it are anything but simple. For an erection to occur, a number of complicated hydraulic events has to happen that cause the penis to fill with blood, and then keep the blood trapped inside the penis for a time.
The “action center” of the penis is the corpora cavernosa, a pair of chambers of spongy tissue on either side of the shaft. To form an erection, nerve signals cause the blood vessels that supply the corpora cavernosa to dilate, so that blood flow to the chambers increases. As the spongy tissue engorges with blood, it collides with an outer sheath of elastic tissue that encases the chambers. This temporarily chokes off the veins that drain the blood back out of the penis, allowing the erection to stabilize.
High blood glucose can adversely affect erections in three ways: hormonal, vascular, and neurologic. On the hormonal front, high blood glucose interferes with the body’s production of nitric oxide, a so-called vasodilator that triggers the hormonal chain reaction that relaxes the blood vessels and allows the corpora cavernosa to fill with blood. On the vascular front, high blood glucose can be incredibly damaging to blood vessels, potentially reducing the ability of the supply arteries to dilate. In a similar fashion, nerve damage from high blood glucose can affect both sensation and nerve signaling involved in the erection process.