Hypoglycemia unawareness is present in about 20 percent of people with Type 1 diabetes. Normally a low will be recognized by symptoms such as shaking and sweating caused by releasing stress hormones. However, stress hormones deplete after several lows, resulting in a loss of warning symptoms. This impairs thinking before the person recognizes they are low, so they may be unable to treat the low. Unless the hypoglycemia is recognized and treated by another person, serious problems like seizures or coma can occur.
Repeated lows impair the body’s release of stress hormones. Because of this anyone with Type 1 diabetes can experience unawareness following a series of frequent lows close together. Nighttime lows in particular deplete stress hormones because these episodes typically last longer.
Glucagon, a major counter-regulatory hormone that causes the liver to release glucose, is the body’s backup mechanism to bring a person out of a low if they are unaware and unable to treat the low themselves. Unfortunately, this response is reduced in most people with Type 1 diabetes after two to ten years. Women have less counter-regulatory hormone response than men do, and so are more prone to unawareness because of reduced hypoglycemia symptoms.
The lower a person’s average blood sugar, the higher the risk for hypoglycemia unawareness. Research (http://care.diabetesjournals.org/content/15/4/582.full.pdf) shows that people wake up for less than half of the lows that occur at night. Not realizing night lows are occurring makes daytime hypoglycemia unawareness more likely.
Unrecognized night lows and frequent lows cause hypoglycemia unawareness. Warning signs become less obvious because glucagon is released more slowly and in smaller concentrations after a prior severe low blood sugar. Avoidance of night and frequent lows allows many people to regain their warning symptoms when they become low.
To reverse hypoglycemia unawareness, set blood sugar targets higher, readjust doses to closely match your diet and exercise, and stay more alert to physical warnings for 48 hours following a low blood sugar. Deal quickly with problems arising from stress, depression, and other sources of poor self-care. Avoid alcohol or limit consumption to less than one or two drinks a day, to avoid shutting off the liver’s release of glucose. On active days, reduce insulin during increased activity and for several hours afterward. Use a continuous glucose monitor to alert you of lows, and confirm readings with a test strip before treating the result. Frequent testing is critical for making needed basal or bolus reductions and to prevent lows before they happen. A continuous glucose monitor can wake you up during nighttime lows and enable early treatment. A little lost sleep is much better than a life-threatening low.