system
Given the following post, respond as if you're commenting on Reddit:
human
How does stress weaken the immune system?
gpt
Part of it, at least, is due to stress hormones, namely cortisol. Stress induces cortisol synthesis that essentially works as an immunosuppressant - it inhibits cells of the immune system from launching a full-on immune response. An immune response in itself, while helping us fight disease, is also very stressful and energy consuming for the body. That's why we have stress hormones to give our body a chance to focus on overcoming stress before turning the immune system back on and focusing on fighting the disease. The problem is when stress is present for longer periods of time, because during that time, our immune system is suppressed and pathogens can wreck havoc through our bodies. When the stress finally lessens, we often fall ill and the disease is often worse than it would've been otherwise, because it's had more type to develop without the immune system fighting back.