Which factor does NOT weaken the immune system?

Regular exercise is known to strengthen the immune system rather than weaken it. Engaging in physical activity has several positive effects on immune function. It helps improve circulation, allowing immune cells to move freely throughout the body, which enhances their ability to detect and respond to pathogens. Additionally, moderate exercise has been shown to reduce inflammation and promote the overall health of various bodily systems, including the immune system.

In contrast, chronic illness, stress, and poor nutrition can have detrimental effects on immune function. Chronic illnesses can drain the body's resources and energy needed for effective immune responses, while stress can lead to the release of hormones that suppress immune activity. Poor nutrition means that the body may lack essential vitamins and minerals vital for maintaining a robust immune system. Each of these factors can compromise immune responses, making an individual more susceptible to infections and illnesses. By engaging in regular exercise, individuals can bolster their immune defenses and enhance their overall health.