Final answer:
Hypoglycemia is defined as a serum glucose level below 60-70 mg/dL, which can lead to numerous symptoms due to a lack of glucose for the brain.
Step-by-step explanation:
The serum glucose level that qualifies for hypoglycemia is a blood glucose concentration below 60-70 mg/dL. In individuals with hypoglycemia, symptoms such as convulsions, sweating, weakness, tremors, fainting, and possibly even coma and death can occur due to the insufficient supply of glucose to the brain, which exclusively uses glucose as its energy source. These critical symptoms emerge because the brain is deprived of its primary fuel.
Under normal fasting conditions, or post-absorptive state, blood glucose levels range between 60-90 mg/100 mL. This level represents a healthy baseline for non-diabetic, fasting individuals. In contrast, a level of blood glucose below 60 mg/dL indicates a hypoglycemic state, warranting medical attention due to the risks associated with inadequate glucose availability to the brain and other tissues.