Diabetes and Your Nervous System

In people with diabetes, the nervous system can be affected in many ways, causing multiple problems termed neuropathy. These problems can include numbness of sensation, increased pain sensation, decreased muscle control and function, and difficulty with control of other organs such as the bladder and bowel. There can also be significant problems with neurological control of the heart and blood vessels, which can lead to abnormal heart rhythms and significant fluctuations in blood pressure.

Those with diabetes who have decreased sensation can develop problems relating to the inability to sense pressure pain. For instance, if the soles of your feet do not sense pressure well, it will be difficult for you to know whether or not your shoe fits well. Therefore, when there is a specific pressure point on a part of your foot that you cannot feel, it will lead to significant breakdown of the skin, causing an ulcer that can become infected. This condition is called peripheral neuropathy; it is theorized that is directly caused by the by-products of hyperglycemia.

A decrease in sensation can also lead to a significant breakdown of joints, which in turn can lead to fractures and deformities. For example, if you moved a certain way that caused pain in your foot, you would investigate the cause and come up with the solution to stop the pain. But if you don't have the ability to sense this pain (the body's early warning system), you won't notice the damage until a visible change occurs. Such a change may be anything from swelling and redness to a drop in your arch, causing a large deformity of your foot. Foot care is very important for all people with diabetes. Your doctor can order a test called an electromyelogram (EMG) to look at your peripheral nerve function and health.

Damage to the nerves that control certain body parts can occur, resulting in dysfunction of the specific areas. This is referred to as autonomic neuropathy. These areas can include organs such as muscles, heart, blood vessels, stomach, intestine, and bladder. For example, if the nerves to your hand muscles were damaged, you may notice that you have decreased ability to manipulate small objects such as writing utensils. Similarly, if the nerves that control gastric motility (which is required for normal food digestion) are damaged, you may experience symptoms ranging from nausea and vomiting to constipation or diarrhea.

Furthermore, if the nervous system's interaction with the blood vessels is disrupted, this can result in the inability to control your blood pressure. The body's blood pressure normally is lower while lying or sitting than when standing. The nervous system helps increase the blood pressure when we go to the standing position. If your nervous system is impaired from diabetes, you may notice symptoms such as light-headedness, dizziness, or even loss of consciousness when you attempt to go from a lying or sitting position to a standing position. More importantly, normal autonomic nerve function is critical to exercising safely. I will discuss this more in chapter 4.