Symptoms of hypoglycemia can be organized into 2 primary categories: neurogenic and neuroglycopenic. Neurogenic symptoms are the result of activation of the sympathetic nervous system when glucose levels drop too low. These include shaking or tremors, a pounding heart, nervousness or anxiety, sweating, and tingling. Neuroglycopenic symptoms arise when insufficient glucose is available to fuel the brain. These include warmth, confusion, and drowsiness. During prolonged, severe hypoglycemia dramatic brain dysfunction can occur, potentially leading to coma and death (Towler 1993; MedlinePlus 2012).
Hypoglycemic symptoms including anxiety, sweating, tremors, and fatigue do not always correlate with glucose levels (Nippoldt 2013). Individuals with low glucose levels may be asymptomatic or unaware of their hypoglycemia, and others with normal glucose levels may display hypoglycemic symptoms (Bakatselos 2011; Alken 2008; Palardy 1989).