Which sign is commonly associated with acute pain?

• A. Grimacing
• B. Restlessness
• C. Increased heart rate
• D. Normal heart rate

Answer: (C)

Acute pain triggers the body's fight-or-flight response, activating the sympathetic nervous system. This releases stress hormones that raise the heart rate to prepare the body for action. Among the options, an increased heart rate is the most consistent physiological sign of acute pain, making it a reliable cue for clinicians to notice. Grimacing and restlessness can occur with pain, but they are behavioral cues that vary between individuals and situations. A normal heart rate would not indicate pain, and while some factors like certain medications or conditions can blunt the heart-rate response, the elevated heart rate remains the classic sign associated with acute pain.