## **Core Concept**
β-blockers are a class of medications that inhibit the effects of β-adrenergic receptors, which are part of the sympathetic nervous system. They are commonly used to treat hypertension, angina, and certain arrhythmias. In the context of hypoglycemia, β-blockers can mask some of the typical symptoms.

## **Why the Correct Answer is Right**
The correct answer, **tachycardia**, is a symptom of hypoglycemia that β-blockers do not mask but rather prevent from occurring. Normally, in response to hypoglycemia, the body releases stress hormones like adrenaline (epinephrine), which causes an increase in heart rate (tachycardia), among other effects. β-blockers block the β-adrenergic receptors in the heart, thereby preventing tachycardia. However, they do not prevent the other symptoms of hypoglycemia like sweating, tremors, and anxiety but can mask the awareness of hypoglycemia by preventing the heart rate from increasing.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Sweating is a symptom of hypoglycemia that is not mediated by β-adrenergic receptors but by the sympathetic nervous system's stimulation of sweat glands directly or through α-adrenergic receptors. β-blockers do not prevent sweating.
- **Option B:** Tremors are another symptom of hypoglycemia that β-blockers can partially mask because tremors are partly mediated by β-adrenergic receptors.
- **Option C:** Anxiety or nervousness during hypoglycemia is also influenced by the body's stress response, which β-blockers can modify but not completely eliminate.

## **Clinical Pearl / High-Yield Fact**
A key clinical point to remember is that β-blockers can make it difficult to recognize hypoglycemia because they prevent the typical tachycardic response. This is particularly important for diabetic patients on β-blockers, as they may not experience the usual warning signs of hypoglycemia.

## **Correct Answer:** . Tachycardia