Which factor can increase respiratory rate beyond fever?

• A. Physical exertion
• B. Chronic lung disease
• C. Anxiety
• D. All of the above

Answer: (D)

Respiratory rate climbs when the body’s need to exchange gases increases or the breathing drive is amplified. Fever does raise rate, but several other situations can push it higher too. Physical exertion boosts metabolic activity and CO2 production, so ventilation speeds up to meet tissues’ needs. Chronic lung disease often means the body is working harder to oxygenate blood, sometimes with lower oxygen levels, prompting a faster breathing rate to compensate. Anxiety stirs the sympathetic system and can accelerate breathing even without physical activity, leading to tachypnea. Because each of these factors can increase breathing rate independently of fever, the answer that includes all of them is the best choice.