Which factor would cause an increase in pulse rate?

• A. Hypothermia
• B. Smoking
• C. Sleeping
• D. Aging

Answer: (B)

Pulse rate rises when the body experiences sympathetic stimulation or exposure to stimulants. Nicotine from smoking acts as a stimulant, triggering the release of adrenaline and other catecholamines that speed up the heart. This direct chemical stimulation increases the heart’s pacing, leading to tachycardia. Carbon monoxide in smoke can also lower oxygen delivery, making the heart work harder and potentially pushing the rate higher as a secondary effect. In contrast, hypothermia tends to slow the heart to conserve heat, sleeping reduces metabolic demand and lowers heart rate, and aging doesn’t produce an acute rise in resting pulse in the same way nicotine does. So smoking is the factor most likely to increase pulse rate.