Which of the following is a common sign of heart failure in older adults?

Unexplained dyspnea, or difficulty breathing, is a common sign of heart failure in older adults due to the heart's decreased ability to pump blood effectively. This condition can lead to fluid buildup in the lungs, causing symptoms such as shortness of breath, particularly during exertion or while lying flat. Older adults are particularly susceptible to heart failure, and symptoms can be subtle or mistaken for other conditions, making it essential to recognize dyspnea as a key indicator.

Addressing the other signs, frequent headaches may occur for various reasons, such as tension or migraines, but they are not specific indicators of heart failure. Sudden weight gain can occur due to fluid retention in heart failure, but it may not be the most common initial presenting symptom, often presenting with more established fluid retention or worsening function. Increased energy levels would be contrary to the expected signs of heart failure, as patients typically exhibit fatigue and reduced exercise tolerance.