Which of the following actions can help alleviate asthma symptoms?

Breathing out, especially in a controlled manner, can help alleviate asthma symptoms by enabling the individual to expel trapped air from the lungs. Many people with asthma experience difficulty fully exhaling due to narrowed airways or inflammation. By focusing on exhalation, particularly through techniques like pursed-lip breathing, patients can help reduce trapped air, improve airflow, and relieve feelings of breathlessness. This action can also help prevent the airways from tightening further, thereby making it easier to breathe.

While the other options may play a role in general respiratory well-being or comfort, they are not as directly effective in relieving acute asthma symptoms. For instance, while using a humidifier can help maintain optimal moisture levels in the air, and drinking plenty of water supports overall hydration, these actions do not specifically address the physiological aspects of asthma attacks. Avoiding cold air can be beneficial for some individuals who are sensitive to temperature changes, but it is not as immediate a remedy for alleviating symptoms as focused and controlled breathing techniques.